Do all preamps sound alike?
Wylie Williams
on this and other audio newsgroups. This post is not on that subject,
and I for one would appreciate not seeing it creep into this thread, as
this subject gets enough play already. I t occurred to me that in all
this hubub about amplifiers somehow preamps are ignored.
So the question is "Do all preamps sound alike? If the answer is
something like "Yes, so long as they are competently designed", then
specifying what constitutes "competent design" for a preamp would help
immensely.
Wylie Williams
The Speaker and Stereo Store
Saint Louis, Missouri
Midlant
played with the couple I have here at home. Not a huge difference but
some. Then went to the local guys and chatted with. Yep, huge difference
and I needed to hear to believe. Came home, grabbed my main preamp and
went back to the store.
The set me up with a nice system using Rotel's top line preamp. All
other components including the B&W 802's were much nicer/expensive.
The Rotel had (to me) an artificial mid-range. Vocals were in your face
and grainy. My main preamp is still the Acurus RL-11. Not one thing
about it is unnatural or bloated. It's detailed, precise, and does what
a preamp is supposed to do, convey the music without altering it. So,
yes with my experience there is a difference. Compare before you buy or
change.
John
"Wylie Williams" <wyli...@charter.net> wrote in message
news:ckfce...@news3.newsguy.com...
Stewart Pinkerton
wrote:
> Whether all power amps sound alike is a regular topic of discussion
>on this and other audio newsgroups. This post is not on that subject,
>and I for one would appreciate not seeing it creep into this thread, as
>this subject gets enough play already. I t occurred to me that in all
>this hubub about amplifiers somehow preamps are ignored.
> So the question is "Do all preamps sound alike? If the answer is
>something like "Yes, so long as they are competently designed", then
>specifying what constitutes "competent design" for a preamp would help
>immensely.
How about "If the gain is set to unity, then the preamp should add no
audible colouration when compared to a bypass cable". That shouldn't
be very tough to set up and test, if you have a second preamp with at
least two line inputs of equal sensitivity.
--
Stewart Pinkerton | Music is Art - Audio is Engineering
Nousaine
Of my current stable of preamplifiers none of them sound different from one
another until I use one of the controls to alter the sound. IOW operating with
a straight-thru functionnone of them changes the sound in anyway except for
gain.
Robert C. Lang
I consider the preamp to be the heart and soul of the audio
electronics of my system; far more than the amplifier. That is, it has
been my experience (discovered quite by accident less than 5 years
ago) that the preamp has a far greater influence on the sonic
character of the system than does the amplifier (assuming, of course,
that the amplifier is adequate to handle the workload).
There *can* be marked audible differences in pre amps, which is
probably why you rarely see it debated. In fact, often casual
listening can pick up differences that may exist. One thing I found
that is that the differences can be pronounced in the frequency
extremes, especially when comparing tubes and solid state pre amps.
A few years ago I conducted an in-home audition of the Audible
Illusions 3A and subsequently 4 other pre amps in my system. It was
fairly easy to use specific passages is selected recordings to point
out differences, some marked.
To make a long story short the 3A simply did not fit into my system.
My detailed comments can be found at:
http://www.audioreview.com/Preamplifiers/Audible
Illusions/PRD_118448_1591crx.aspx#reviews
My "review" is dated February 27, 2000.
I thought I gave the 3A a favorable review, 4 out of 5 stars. But I
guess some of my comments struck a nerve and I got a couple of pieces
of "hate mail". To my real surprise Audible Illusions, the
manufacturer, itself sent me an Email. Their Email was professional
just wanting to get to the bottom of the problem I had. After some
informative exchanges, they too agreed that the 3A would not work well
in my system. There were no sonic aberrations, per se, an actually it
sounded good but it was clear that it was dissimilar to my previous
pre amp (actually it may have sounded "better").
I have since learned that there are a lot of pre amps that are more
"transparent" but not necessarily "better" than the 3A. I eventually
settled on a passive pre that performed much better in my system than
the 3A.
Of course, sound aside, pre amps differ so greatly in features and
layout those differences can be more influential in your choice.
Because while the sound may differ from pre to pre it nothing like (in
most cases) the sound differences in speakers.
The bottom line is that, when it comes to the pre amp, there is
absolutely no substitute for an in-home audition.
Georg Grosz
You could say that a competent design does not add unwanted audible
artifacts, but that is subjective. Say that a competent design does
not add any audible artifacts. That's getting closer, but you need
some sort of reference against which to compare a design.
Let's say that a design is competent if it cannot be distinguished
from an independent design in a blind test. At the current state of
the art, this is a practical and objective definition. I would go even
further and say that a competent designer should be able to produce a
competent design without any testing at all. (Except for the usual
"smoke test" to find out if any of the IC's are inserted backwards).
In terms of power amps vs. preamps, the distinction is somewhat
arbitrary. Both amplify. Historically, a "preamp" was the circuit that
managed the physical interface with an analog sensor or signal source.
For instance a phono pickup required a different preamp than a
microphone. In general usage, an audio preamp also contains the
switches and controls, whereas a power amp often has only input and
output terminals.
The criteria for preamps and power amps should be the same, except
that there is an additional burden on preamps. Suppose a preamp has
tone controls, then it will obviously introduce an artifact when the
controls are cranked. But again, two preamps that are designed to have
the same control function should sound the same. Real preamps may be
distinguished by how the designer has chosen to make these controls
behave -- this is a way for preamps to sound different.
If the two preamps were given a fair double blind test, and sounded
different, one of them would probably be an incompetent design. If
it's a "sighted" test, then the best explanation is the influence of
expectations on perception.
Tat Chan
> Of my current stable of preamplifiers none of them sound different from one
> another until I use one of the controls to alter the sound. IOW operating with
> a straight-thru functionnone of them changes the sound in anyway except for
> gain.
What about active and passive pre-amps? Looking through the archives,
one tends to find (subjective) stereotypical descriptions like
active pre-amps --> dynamic sounding
passive pre-amps --> lifeless in comparison
Chung
Competent *line-level* preamps sound alike. Competence in a preamp means
flat frequency response, low distortion and noise. In other words, close
to a straight wire with gain. In addition, the volume control should
provide accurate left-right tracking throughout its range. I have seen
cheaper preamps that have fairly gross tracking errors that make it easy
to tell them apart from others. Digital volume controls can greatly
alleviate this problem. By the way, designing a competent line-level
preamp is much easier than designing a competent power amp. For the
consumer, features (like the number of inputs and outputs, type of tone
controls, etc.) and aesthetics probably are the important
differentiators in preamps.
Phono-preamps are much less alike. RIAA equalization errors are often
noticeable.
Nousaine
>Nousaine wrote:
>> A "passive" pre-amplifier can be nothing more than a switch and an
>attenuator.
>> Maybe they should be called a post-amplifier.
>
>"post-amplifier"???
>
>Btw, if a passive pre-amp just contains a switch and attenuator, why do
>some of them cost quite a bit?
>
>Is the attenuator (volume pot?) that expensive, or is it just the profit
>margin?
As far as I can tell it is just margin. Afterall what IS the FUNCTION of a
preamplifer other than switching, balancing of input levels and certain
equalization functions (tone controls and phono-eq; tone controls, fader and
balance and input loops)?
What does a passive preamplifier offer? Only switching and attenuation or
passive-level eq (the latter of which always includes attenuation)?
Because it has no gain it cannot match input levels or perform any function
other than input switching without loss.
Tat Chan
> On 13 Oct 2004 02:42:56 GMT, Tat Chan <le_kin...@hotmail.com>
> One does indeed find these comments, but they're fundamentally
> rubbish. A passive controller cannot possibly reduce dynamics, since
> it's basically just a switch and a volume control - as you'll find
> inside any active preamp. Now, if your active preamp introduces some
> compression, then it may *sound* more dynamic, but it ain't really so
> - as any radio station sound engineer can confirm.
>
I have heard that radio transmissions are compressed to make them sound
more "punchy" on cheap portable radios and boom boxes, but how does
compression make the sound more dynamic? Doesn't compression just bring
the peaks and troughs closer together, hence reducing the dynamic range?
Btw, didn't you note before that the Audiolab 8000A and 8000S integrated
amps sound different, due to the different pre-amp sections in each amp?
Robert C. Lang
> Maybe they should be called a post-amplifier.
Yes, by very definition a preamplifier is an electronic circuit or
device. I usually steer clear of referring to a "preamp" when
referring to it's passive "cousin" calling it instead a "passive line
stage" as I steadfastly did in my first post to this thread. But then,
of course, "passive line stage" can and does cause confusion in a
discussion among audiophiles (although not to the degree it did, say,
5 years ago before people began learning more about the concept).
With that said, an oxymoron, though it may be, the referring to a
passive line stage as a "passive preamp" is probably part and parcel
to our English language. There are literally dozens of words in the
English language that, when examined, make no sense, but are,
nonetheless, clearly understood as to meaning. Some common misnomers,
"American Indian" (talk about a major historical and linguistic
blunder), "Brazilian grass" (it won't even grow in Brazil and it's not
grass), "cat gut" comes from sheep, "rice paper" (not made from rice),
"Panda Bear" (no genetic connection to bears), whalebone (not even
close to bone), etc., etc.
While I believe it is *very* important to understand the differences
between "pre amp" and "passive line stage" to have an intelligent
discussion on the topic, the two will probably evermore be used
interchangeably. That is, the use of "passive" before "preamp", will
probably be sufficient to distinguish one from the other.
Robert C. Lang
Robert C. Lang
> Btw, if a passive pre-amp just contains a switch and attenuator, why do
> some of them cost quite a bit?
>
> Is the attenuator (volume pot?) that expensive, or is it just the profit
> margin?
It's probably a combination of things including, materials, limited
distribution and sales compared to active pres, profit margins,
design, whether it employs RCA or balanced connecters, etc. But
certainly materials cost is important.
Resistor based passive designs have inherent issues that must be tamed
to bring the passive closer to the music. The primary problem with
typical high end resistors, including many of the lower cost Vishay
resistors is brightness (high frequency distortion). At least one
manufacturer I know of claims that their passives get around these
problems by using nothing top-of-the-line Vishay S102 resistors in a
stepped volume control. They claim that the absolutely resistive load
they offer to the source means instant rise time that protects
dynamics and high frequency accuracy without adding audible
brightness.
I don't know what is considered expensive when it comes to parts in
audio equipment. But from whay I understand from comments made over
the past few years is that a resistor based passive is no better than
the resistor that it employs. Further, that Vishay resistors are, in
general, more expensive than most and that the top-of-the-line Vishay
102s, in particular, are the best they produce. Also, one passive may
employ a lot more of a specific quality resistor than a competitor (in
this case the more the better).
A poorly designed passive, with cheap materials, will probably have
more of an audible negative impact that a poorly designed active pre
with cheap materials, because there is less to hide behind.
Robert C. Lang
Stewart Pinkerton
>Tat Chan le_kin...@hotmail.com wrote:
>
>>Nousaine wrote:
>>Btw, if a passive pre-amp just contains a switch and attenuator, why do
>>some of them cost quite a bit?
>>
>>Is the attenuator (volume pot?) that expensive, or is it just the profit
>>margin?
>
>As far as I can tell it is just margin.
It depends. The parts for my own passive controller cost more than
$800, being a Penny&Giles studio pot and a bunch of Pickering
Ruthenium-tipped relays, with Neutrik gold-clad XLR connectors and a
very smooth power supply (for the relays). OTOH, I can't see where the
sales price comes from when it's just a box with an Elma Switch and an
Alps pot, total parts cost not exceeding $100, more like $50 in OEM
quantity.
Stewart Pinkerton
wrote:
>Stewart Pinkerton wrote:
>
>> On 13 Oct 2004 02:42:56 GMT, Tat Chan <le_kin...@hotmail.com>
>> wrote:
>>
>>
>>>Nousaine wrote:
>>>
>>>
>>>>Of my current stable of preamplifiers none of them sound different from one
>>>>another until I use one of the controls to alter the sound. IOW operating with
>>>>a straight-thru functionnone of them changes the sound in anyway except for
>>>>gain.
>>>
>>>What about active and passive pre-amps? Looking through the archives,
>>>one tends to find (subjective) stereotypical descriptions like
>>>
>>>active pre-amps --> dynamic sounding
>>>passive pre-amps --> lifeless in comparison
>>
>>
>> One does indeed find these comments, but they're fundamentally
>> rubbish. A passive controller cannot possibly reduce dynamics, since
>> it's basically just a switch and a volume control - as you'll find
>> inside any active preamp. Now, if your active preamp introduces some
>> compression, then it may *sound* more dynamic, but it ain't really so
>> - as any radio station sound engineer can confirm.
>>
>
>I have heard that radio transmissions are compressed to make them sound
>more "punchy" on cheap portable radios and boom boxes, but how does
>compression make the sound more dynamic? Doesn't compression just bring
>the peaks and troughs closer together, hence reducing the dynamic range?
This does however make the transmission sound louder, and you can hear
more 'low level' detail - because of course it's *not* low-level any
more! Just like a vinyl cutting master, in fact........
>Btw, didn't you note before that the Audiolab 8000A and 8000S integrated
>amps sound different, due to the different pre-amp sections in each amp?
Yes, but I don't know why that is.
Robert C. Lang
> What about active and passive pre-amps? Looking through the archives,
> one tends to find (subjective) stereotypical descriptions like
>
> active pre-amps --> dynamic sounding
> passive pre-amps --> lifeless in comparison
Your reference to "stereotypical descriptions" is right on target;
especially at it applies to passive line stages. I'm glad that you
raised the topic because there is a lot of misunderstanding among
audiophiles about passive line stages relative to active pres.
Unfortunately, many audiophiles have the perception about passives
that staunchly reflects the stereotype you put forth. It's a fallacy.
Such perceptions of passives are an over generalization and carelessly
old fashion. There are certainly passives that help perpetuate the
fallacy? But I am *positive* that they were either poorly designed, in
which case they (hopefully) don't make it in the market place, or
poorly matched in there respective systems or both.
Some of the chief disseminators of this fallacy are high-end audio
dealers who are 1) simply behind the times, 2) biased because they
don't carry low profit margin passives, or 3) simply not
knowledgeable.
I have seen/heard a lot of talk about passives and their inherent
weaknesses but I have never seen a compelling reason why a well
designed, well matched passive cannot audibly perform with the very
best active pres on the market. And at 20% to 30% of the cost of an
active pre!
But perhaps the fallacy is waning. I was thumbing through the October
issue (Recommended Component Issue) of Stereophile and to my surprise
I see a Placette Passive is rated as a Class A component. I'm not
suprised that it is highly rated. Sonically, it certainly deserves it.
What is surprising is that this $1000 product is rated Class A. While
there may be notable exceptions, it is my perception that a line stage
no matter how good it may sound will be lucky to get a C let alone a B
rating if it costs "only" $1000. But there the Placette is lumped
together with products costing $5000, $10,000, $20,000, $25,000, etc.
The average cost of the 23 pre amps in the Class A group is a whopping
$13,600! But there the Placette stands going toe-to-toe with arguably
the very best. Not bad for a component that is sold direct and with a
limited ad budget. I have seen Placette ads in some audio magazines (I
don't remember which ones). I don't recall if they advertise in
Stereophile.
Robert C. Lang
Bob Ross
>
> I have heard that radio transmissions are compressed to make them sound
> more "punchy" on cheap portable radios and boom boxes, but how does
> compression make the sound more dynamic? Doesn't compression just bring
> the peaks and troughs closer together, hence reducing the dynamic range?
>
It's not so much that compression makes things "more" dynamic as it
simply changes the dynamics...and as you point out, more often it does
so by reducing the peak to average ratio, which is really making
things "less" dynamic! However, savvy engineers will delay the onset
of the compressor's action, allowing the natural peak transient to
occur unmodified before gain reduction kicks in. This makes the music
sound more "punchy" because it changes the envelope of each transient;
it emphasizes the attack disproportionately.
Then once they've skewed the original dynamics with a compressor to
get it more "punchy", they run the whole thing through a limiter to
prevent overshoot. Smart engineers will adjust the attack & release
parameters of the limiter so it's not simply undoing what the
compressor did.
(The operative word being "Smart".)
Harry Lavo
news:ckkri...@news1.newsguy.com...
But it can use hundreds of expensive Vishay 1% tolerance resistors in doing
so, as well as very expensive capacitors and pots, and it can be hand-built
in small quantities. These things do add cost...keep in mind that your auto
dealer probably now charges over $50 per hour for work on your car. Apply
that to hand work on a preamp plus parts cost with a 5X markup (to retail,
standard manufacturing practice) and the charges add up pretty quickly.
B&D
<br...@berklee.net> wrote:
I have a question - given the dynamic range of live music (I have no idea
what that might be) - is it possible to record it faithfully on CD or other
media without at least some compression?
B&D
<harry...@rcn.com> wrote:
> Apply
> that to hand work on a preamp plus parts cost with a 5X markup (to retail,
> standard manufacturing practice) and the charges add up pretty quickly.
That markup certainly applies to our hobby - but high volume consumer gear
and other high volume products such as computers do not have such markups -
it is closer to 2-3x and sometimes as low as 1.5x or less!
Tat Chan
> On 14 Oct 2004 00:35:10 GMT, Tat Chan <le_kin...@hotmail.com>
> wrote:
>
>
>>
>>I have heard that radio transmissions are compressed to make them sound
>>more "punchy" on cheap portable radios and boom boxes, but how does
>>compression make the sound more dynamic? Doesn't compression just bring
>>the peaks and troughs closer together, hence reducing the dynamic range?
>
>
> This does however make the transmission sound louder, and you can hear
> more 'low level' detail - because of course it's *not* low-level any
> more! Just like a vinyl cutting master, in fact........
Sorry, I have no experience with vinyl.
>
>
>>Btw, didn't you note before that the Audiolab 8000A and 8000S integrated
>>amps sound different, due to the different pre-amp sections in each amp?
>
>
> Yes, but I don't know why that is.
So one of the pre-amps is incompetent then?
Btw, I thought you would have worked out why ... to use an Americanism,
"it ain't rocket science!"
;)
Harry Lavo
news:cknga...@news1.newsguy.com...
Sorry, it ain't so but may be we are referring to different things. I
referenced retail, not manufactuere's selling price.
Generally audio companies try to give a retailers a 40% margin from
"list"...then there is usually a distributor or a wholesaler in there who
takes 15% or so of what remains (15% x 60% = 9-10% of retail). That leaves
the manufacturer with a selling price of about 1/2 of retail. Of that
amount, generally his cost of sale has to average no higher than 50-60% to
allow him to cover G&A and selling expense and any profit. So his total
cost is 50-60% x 50% of retail, or 25-30% of retail. This cost in turn is
divided when all the cost accounting is completed, into labor and cost of
components. Depending on the type of business one will generally be higher
than the other. But in a low volume operation component costs will usually
be less than labor, and in a high volume operation, more than labor. So
lets split the two and say 50% of total cost is component cost. That's 50%
of 25-30% of retail, or 12.5-15% of retail. Thats a 6x-8x markup to retail.
Only the higher volume, more established manufactures are likely to get it
to 5x.
For example, in high volume consumer goods such as groceries and sundries
(toothpaste, etc.) 20% of retail for component cost (5x markup) would be a
good average although retail margins tend to be lower in those industries,
so if the retail margin were more like audio it would be a lesser percentage
and a higher markup.
BTW I've worked in those industries as well as in audio manufacturing
(briefly) for a well known manufacturer. I'm not guessing at the general
parameters. You can argue specifics of any one number, but you can't get
too far from these ratios in the end.
Chung
> Tat Chan <le_kin...@hotmail.com> wrote in message news:<ckkhj...@news4.newsguy.com>...
>
>> Btw, if a passive pre-amp just contains a switch and attenuator, why do
>> some of them cost quite a bit?
>>
>> Is the attenuator (volume pot?) that expensive, or is it just the profit
>> margin?
>
> It's probably a combination of things including, materials, limited
> distribution and sales compared to active pres, profit margins,
> design, whether it employs RCA or balanced connecters, etc. But
> certainly materials cost is important.
>
> Resistor based passive designs have inherent issues that must be tamed
> to bring the passive closer to the music.
Why would resistor based passive designs have inherent issues? What are
the other passive designs based on? Potentiometers? How does one bring
the passive closer to the music?
> The primary problem with
> typical high end resistors, including many of the lower cost Vishay
> resistors is brightness (high frequency distortion).
Why would resistors cause high frequency distortion? These resistors are
commonly used at radio frequencies, so why would audio be a problem?
I have used resistors in designing ultra-low distortion instruments, and
I have never found common metal-film resistors to cause non-linear
distortion at audio frequencies. Unless you blow them up, of course.
> At least one
> manufacturer I know of claims that their passives get around these
> problems by using nothing top-of-the-line Vishay S102 resistors in a
> stepped volume control. They claim that the absolutely resistive load
> they offer to the source means instant rise time that protects
> dynamics and high frequency accuracy without adding audible
> brightness.
And you don't question their claim?
>
> I don't know what is considered expensive when it comes to parts in
> audio equipment. But from whay I understand from comments made over
> the past few years is that a resistor based passive is no better than
> the resistor that it employs. Further, that Vishay resistors are, in
> general, more expensive than most and that the top-of-the-line Vishay
> 102s, in particular, are the best they produce.
What separates the "best" resistors from good resistors, besides
tolerance? You can certainly get 1% metal film resistors from Vishay and
other suppliers at low prices.
> Also, one passive may
> employ a lot more of a specific quality resistor than a competitor (in
> this case the more the better).
>
> A poorly designed passive, with cheap materials, will probably have
> more of an audible negative impact that a poorly designed active pre
> with cheap materials, because there is less to hide behind.
By definition, a poorly designed active preamp *will* have great
negative impact.
Stewart Pinkerton
wrote:
>Stewart Pinkerton wrote:
>
>> On 14 Oct 2004 00:35:10 GMT, Tat Chan <le_kin...@hotmail.com>
>> wrote:
>>>Btw, didn't you note before that the Audiolab 8000A and 8000S integrated
>>>amps sound different, due to the different pre-amp sections in each amp?
>>
>> Yes, but I don't know why that is.
>
>So one of the pre-amps is incompetent then?
By definition, yes, the 8000A has a problem.
>Btw, I thought you would have worked out why ... to use an Americanism,
>"it ain't rocket science!"
I didn't care why at the time - I was making a purchasing decision,
not investigating a problem.
Stewart Pinkerton
wrote:
>Resistor based passive designs have inherent issues that must be tamed
>to bring the passive closer to the music. The primary problem with
>typical high end resistors, including many of the lower cost Vishay
>resistors is brightness (high frequency distortion).
Excuse me? Do you have *any* evidence for this extraordinary claim? I
have run sweeps on many resistors, and I find no evidence whatsoever
of *any* distortion products on any of the better types (wirewound,
metal-film or bulk metal), below 100kHz and down to -140dB below a 10
volt rms drive signal. Aside from some parasitic inductance and
capacitance, which of course does not introduce nonlinear distortion,
merely frequency response effects, modern resistors simply don't cause
problems IME - and I was looking for linearity and frequency response
*way* beyond what you'd need for domestic audio!
>At least one
>manufacturer I know of claims that their passives get around these
>problems by using nothing top-of-the-line Vishay S102 resistors in a
>stepped volume control. They claim that the absolutely resistive load
>they offer to the source means instant rise time that protects
>dynamics and high frequency accuracy without adding audible
>brightness.
That's fine if your music system needs to handle MegaHertz signals,
but hardly necessary for audio!
>I don't know what is considered expensive when it comes to parts in
>audio equipment. But from whay I understand from comments made over
>the past few years is that a resistor based passive is no better than
>the resistor that it employs.
True in theoretical terms, but apparently irrelevant in practice - see
below.
> Further, that Vishay resistors are, in
>general, more expensive than most and that the top-of-the-line Vishay
>102s, in particular, are the best they produce. Also, one passive may
>employ a lot more of a specific quality resistor than a competitor (in
>this case the more the better).
That's certainly true, and can make some switched attenuators very
expensive indeed.
>A poorly designed passive, with cheap materials, will probably have
>more of an audible negative impact that a poorly designed active pre
>with cheap materials, because there is less to hide behind.
While that *may* be true, I have not encountered anyone able to hear
the difference between an attenuator made with cheap metal film
resistors and one made with Vishay 102s, which I would agree are
*technically* the best resistors that money can buy. My own passive
controller sacrifices perfect channel tracking in favour of infinite
adjustment, and uses a conductive plastic Penney&Giles pot, as used in
the best recording studio equipment. It droops -3dB at 190kHz in my
system, which I consider to be adequate............
Stewart Pinkerton
>I have a question - given the dynamic range of live music (I have no idea
>what that might be) - is it possible to record it faithfully on CD or other
>media without at least some compression?
Yes. There is no known master tape with a dynamic range of greater
than 80-85 dB, so the 93dB of CD is more than adequate to encompass
the dynamic range of live music, as heard from the front stalls of a
concert hall. In fact, most live performances will have a dynamic
range of about 60-70dB, as the noise floor in a concert hall will
never be lower than 40dB or so.
Tat Chan
Cough! Cough! $800?
I hope it comes with a remote control for that amount of money ...
:)
Tat Chan
> Tat Chan <le_kin...@hotmail.com> wrote in message >
>
>
>
>>What about active and passive pre-amps? Looking through the archives,
>>one tends to find (subjective) stereotypical descriptions like
>>
>>active pre-amps --> dynamic sounding
>>passive pre-amps --> lifeless in comparison
>
>
> Your reference to "stereotypical descriptions" is right on target;
> especially at it applies to passive line stages. I'm glad that you
> raised the topic because there is a lot of misunderstanding among
> audiophiles about passive line stages relative to active pres.
> Unfortunately, many audiophiles have the perception about passives
> that staunchly reflects the stereotype you put forth. It's a fallacy.
>
Like you said, it is a stereotype.
<snip>
> Some of the chief disseminators of this fallacy are high-end audio
> dealers who are 1) simply behind the times, 2) biased because they
> don't carry low profit margin passives, or 3) simply not
> knowledgeable.
>
I would say (2) and (3).
> I have seen/heard a lot of talk about passives and their inherent
> weaknesses but I have never seen a compelling reason why a well
> designed, well matched passive cannot audibly perform with the very
> best active pres on the market. And at 20% to 30% of the cost of an
> active pre!
Agreed,
>
> But perhaps the fallacy is waning. I was thumbing through the October
> issue (Recommended Component Issue) of Stereophile and to my surprise
> I see a Placette Passive is rated as a Class A component. I'm not
> suprised that it is highly rated. Sonically, it certainly deserves it.
> What is surprising is that this $1000 product is rated Class A.
> While there may be notable exceptions, it is my perception that a line stage
> no matter how good it may sound will be lucky to get a C let alone a B
> rating if it costs "only" $1000. But there the Placette is lumped
> together with products costing $5000, $10,000, $20,000, $25,000, etc.
Well, a line stage (or passive pre) shouldn't have any sound, as it should just
be a source selector and volume control. Btw, for $1000, I hope it comes with a
remote!
> The average cost of the 23 pre amps in the Class A group is a whopping
> $13,600!
One has to wonder what sort of audiophile buys a pre-amp worth 5 figures!
Per Stromgren
>
>I have a question - given the dynamic range of live music (I have no idea
>what that might be) - is it possible to record it faithfully on CD or other
>media without at least some compression?
Yes, without any problem!
I measured this myself some time back and came up with the follwing
(see the usenet thread "16 bits is enough, som facts to prove it",
use http://groups.google.se/groups if you would like to read the
thread):
"Analyzed CDs:
1. The Kroumata Percussion Ensemble, track 4 Hierophonie by Y. Taira
BIS CD-232, recorded 1983 by Micahel Bergek.
2. The Rite of Spring by Stravinsky, Redwood Symphony, track 1
Introduction. Clarity Recordings, recorded 1993 by Bob Porter.
Both recordings has subjectively a very low background noise from the
recording venue, and show signs of good care in the recording and
mastering process. My playback equipment have problems playing these
CD:s at the volume required to hear the background noise over the room
noise, because of its limited max SPL (speakers are QUAD ESL-63).
Result:
1. Background noise 65dB, tutti -1dB
2. Background noise 63dB, tutti -1dB
This is about 11 bits, well within the 16 bits that the CD is capable
of. There are still 5 bits (30 dB) left for listening to
'microdynamincs' or 'hearing things in the noise', as some fellow
posters say they do."
It still stands. 11 bits will do, but a few more doesn't hurt, i.e. 16
would be a nice number!
Note: both recordings are all digital (yes son, they had that in
1983!) and have not been compressed in any way.
Per
Tat Chan
I wasn't having a dig at your technical abilities. There was a winkly emoticon
in my original post ...
:)
Stewart Pinkerton
wrote:
>Stewart Pinkerton wrote:
If I changed my name to Mark Levinson, I could no doubt charge $8,000
for it.............
>I hope it comes with a remote control for that amount of money ...
Of course it does! Voice controlled, even:
"Anne, turn the volume up a bit"......................
I also have a magic washing basket - you throw in dirty clothes, and
they reappear a few days later in your clothes drawers, washed and
pressed!
Stewart Pinkerton
wrote:
>Robert C. Lang wrote:
>> The average cost of the 23 pre amps in the Class A group is a whopping
>> $13,600!
>
>One has to wonder what sort of audiophile buys a pre-amp worth 5 figures!
I can't resist a good feed line!
One whose IQ is worth only two figures? :-)
B&D
<le_kin...@hotmail.com> wrote:
From his post, it *sounds* like he built it himself? Stewart?
Robert C. Lang
> On 14 Oct 2004 23:47:08 GMT, lan...@pacbell.net (Robert C. Lang)
> wrote:
>
> >Resistor based passive designs have inherent issues that must be tamed
> >to bring the passive closer to the music. The primary problem with
> >typical high end resistors, including many of the lower cost Vishay
> >resistors is brightness (high frequency distortion).
>
> Excuse me? Do you have *any* evidence for this extraordinary claim? I
> have run sweeps on many resistors, and I find no evidence whatsoever
> of *any* distortion products on any of the better types (wirewound,
> metal-film or bulk metal), below 100kHz and down to -140dB below a 10
> volt rms drive signal. Aside from some parasitic inductance and
> capacitance, which of course does not introduce nonlinear distortion,
> merely frequency response effects, modern resistors simply don't cause
> problems IME - and I was looking for linearity and frequency response
> *way* beyond what you'd need for domestic audio!
I will defer to your empirical conclusions based on your tests. I
should have clarified my response so as to not elevate it to a claim.
My information came directly from two (not one) respected pre amp
designers, both whom could clearly be biased toward materials they use
for their products. I will, however, talk to one of the designers
about *his* claim and report back to the group.
But your conclusions raises more questions (for me) they answer. If
there are no practical or measurable quality differences among
resistors what makes some passive sound better than others (and that
indeed has been my experience)? I realize that there is much more to a
passive (such as design implementation) than merely its resistors.
Also, what parts *can* and *do* make a measurable/audible difference?
You mentioned that your passive had $800 worth of parts. Why does your
passive sound superior to others that you have heard?
Could the designer have gotten away with parts that cost substanially
less with out an audible penalty? I guess what I am asking is if key
parts such as resistors don't make a difference (I'm not trying to put
words in your mouth)
then what is the point of using anything but the cheapest?
>
> That's certainly true, and can make some switched attenuators very
> expensive indeed.
But will they sound better?
Robert C. Lang
Tat Chan
> On 16 Oct 2004 15:09:20 GMT, Tat Chan <le_kin...@hotmail.com>
> wrote:
>
>
>>Stewart Pinkerton wrote:
>>
>>
>>>
>>>It depends. The parts for my own passive controller cost more than
>>>$800, being a Penny&Giles studio pot and a bunch of Pickering
>>>Ruthenium-tipped relays, with Neutrik gold-clad XLR connectors and a
>>>very smooth power supply (for the relays). OTOH, I can't see where the
>>>sales price comes from when it's just a box with an Elma Switch and an
>>>Alps pot, total parts cost not exceeding $100, more like $50 in OEM
>>>quantity.
>>
>>
>>Cough! Cough! $800?
>
>
> If I changed my name to Mark Levinson, I could no doubt charge $8,000
> for it.............
>
is that with or without a tube output stage?
:)
>>I hope it comes with a remote control for that amount of money ...
>
>
> Of course it does! Voice controlled, even:
>
> "Anne, turn the volume up a bit"......................
>
Oh great, voice recognition software built in as well ...
Does it ever go "I'm sorry Dave, I'm afraid I can't do that?"
:)
> I also have a magic washing basket - you throw in dirty clothes, and
> they reappear a few days later in your clothes drawers, washed and
> pressed!
Ah, so you got one of those Wash Iron Food Etc (WIFE) contraptions then?
Do they come with a 3 year warranty and 30 day money back gurantee?
:)
Stewart Pinkerton
Yes, it's a homebrew. I've also built the Elma/Alps version for my TV
sound system, fronting an Audiolab 8000P rather than the Krell in the
main system. As you'd expect from any of my gear, they sound
identical, i.e. just like the input signal. :-)
Robert C. Lang
statements. Please see my reply to his post.
Robert C. Lang
Chung <chun...@covad.net> wrote in message news:<ckpmi...@news2.newsguy.com>...
Stewart Pinkerton
wrote:
>Stewart Pinkerton wrote:
>
>> On 16 Oct 2004 15:09:20 GMT, Tat Chan <le_kin...@hotmail.com>
>> wrote:
>>
>>
>>>Stewart Pinkerton wrote:
>>>
>>>>It depends. The parts for my own passive controller cost more than
>>>>$800, being a Penny&Giles studio pot and a bunch of Pickering
>>>>Ruthenium-tipped relays, with Neutrik gold-clad XLR connectors and a
>>>>very smooth power supply (for the relays). OTOH, I can't see where the
>>>>sales price comes from when it's just a box with an Elma Switch and an
>>>>Alps pot, total parts cost not exceeding $100, more like $50 in OEM
>>>>quantity.
>>>
>>>
>>>Cough! Cough! $800?
>>
>> If I changed my name to Mark Levinson, I could no doubt charge $8,000
>> for it.............
>>
>is that with or without a tube output stage?
Nope, but including 45 kilos of laser-cut magnesium alloy which
doesn't actually do anything....................
>>>I hope it comes with a remote control for that amount of money ...
>>
>> Of course it does! Voice controlled, even:
>>
>> "Anne, turn the volume up a bit"......................
>>
>Oh great, voice recognition software built in as well ...
>
>Does it ever go "I'm sorry Dave, I'm afraid I can't do that?"
No, I have upgraded to the JCN 9000, which fixed those bugs.
>> I also have a magic washing basket - you throw in dirty clothes, and
>> they reappear a few days later in your clothes drawers, washed and
>> pressed!
>
>Ah, so you got one of those Wash Iron Food Etc (WIFE) contraptions then?
>Do they come with a 3 year warranty and 30 day money back gurantee?
No, they come with a lifetime warranty and take all your money......
Bob Ross
> On 15 Oct 2004 03:30:40 GMT, B&D <br...@ix.netcom.com> wrote:
>
> >I have a question - given the dynamic range of live music (I have no idea
> >what that might be) - is it possible to record it faithfully on CD or other
> >media without at least some compression?
>
> Yes. There is no known master tape with a dynamic range of greater
> than 80-85 dB
But the question wasn't whether a CD could capture the dynamic range
of an extant master tape, but whether it could capture the dynamic
range of a live performance.
> In fact, most live performances will have a dynamic
> range of about 60-70dB, as the noise floor in a concert hall will
> never be lower than 40dB or so.
You've never heard music beneath the noise floor in a recording? Or
beneath the noise floor in a concert hall?
Yes, given the dynamic range of MOST live music, 16 bit/44.1k PCM is
an adequate recording medium. And those very few exceptions would
probably be pointless to attempt to store in any medium that exceeds
redbook CD's dynamic range because they would tax the limitations of
the playback equipment...or of the listener's ears.
Stewart Pinkerton
wrote:
Has it indeed? Do you have any *evidence* for this extraordinary
claim?
>I realize that there is much more to a
>passive (such as design implementation) than merely its resistors.
What, you mean like a switch or some relays?
>Also, what parts *can* and *do* make a measurable/audible difference?
None in my experience, so long as you avoid obviously crippled items
such as silver-clad switches or carbon resistors.
>You mentioned that your passive had $800 worth of parts. Why does your
>passive sound superior to others that you have heard?
It doesn't, see my other posts regarding this item.
>Could the designer have gotten away with parts that cost substanially
>less with out an audible penalty?
Yes, specifically an Elma switch and Alps 'Black Beauty' pot, which is
what I use in my TV sound system.
> I guess what I am asking is if key
>parts such as resistors don't make a difference (I'm not trying to put
>words in your mouth)
>then what is the point of using anything but the cheapest?
None at all, sonically. Of course, a P&G pot has a very smooth action
and will last 'forever', as will the ruthenium-tipped relays.
>> That's certainly true, and can make some switched attenuators very
>> expensive indeed.
>
>But will they sound better?
Not in my experience, and I've built attenuators using Vishay S102s,
which is as good as it gets technically.
Chung
How about the choice of resistor values? Too low, and you risk loading
the sources, and too high, you have too much high frequency droop and noise.
The biggest problem with passive preamp is that (a) there is no voltage
gain and buffering, and (b) the capacitance of the cable at the output
could affect the frequency response.
> Also, what parts *can* and *do* make a measurable/audible difference?
Matching of left and right channels, by using accurate resistors.
Quality of the switches/relays.
> You mentioned that your passive had $800 worth of parts. Why does your
> passive sound superior to others that you have heard?
He actually did not say that.
> Could the designer have gotten away with parts that cost substanially
> less with out an audible penalty? I guess what I am asking is if key
> parts such as resistors don't make a difference (I'm not trying to put
> words in your mouth)
> then what is the point of using anything but the cheapest?
Tolerances. Good switches are more expensive. Aesthetics (mechanical
design).
>
>
>>
>> That's certainly true, and can make some switched attenuators very
>> expensive indeed.
>
> But will they sound better?
Better left-right tracking is good.
Wylie Williams
> If the two preamps were given a fair double blind test, and sounded
> different, one of them would probably be an incompetent design.
I wish I had take more Philosophy classes that worked through logical
thinking. Somehow when I make a post asking "Do preamps sound alike?"
and there are a number of answers like this I imagine myself doing a
comparison of two preamps, hearing a difference, then asking myself
"Which one is the incompetent one. Let's check the specs. Hmmm, both
have excellent specs. Could it be that both of them are incompetent in
different ways?" At that point to reach a conclusion I would either
have to begin conducting technical research beyond my education or just
deciding I like one better than the other, and start comparing it to
others until I find the one I like best. At least I am qualified to do
that. But then I have just thrown objectivity out the window. Or should
I read audiophile magazines that have access to more preamps than I will
ever be able to audition? No, can't do that they are subjective. But
then so am I. Must be objective, but don't have the tools. I know,
I'll post on RAHE. No, I did that and the results were definitely
mixed. I must restart my train of thought as I seems to have acquired a
circular track. Where is the exit?
Wylie Williams
Chung
So you don't like (some of) the answers that you received? Where is the
circular track?
Let me try to summarize the answers for you:
(1) Some people believe that preamps sound very different from one another.
(2) Some people believe that preamps should sound alike, but due to
implementation issues, some sound different (due to poor designs).
(3) Some people think that they sound alike under DBT conditions.
(4) Some people believe that phono preamps can sound different.
So, why are you not happy with the answers? Again, where is the circular
track?
By the way, if you ask the question "Do all cables sound alike?", you
would probably get the same answers.
Tat Chan
> On 17 Oct 2004 14:40:29 GMT, Tat Chan <le_kin...@hotmail.com>
> wrote:
>
>
>>Stewart Pinkerton wrote:
>>
>>is that with or without a tube output stage?
>
>
> Nope, but including 45 kilos of laser-cut magnesium alloy which
> doesn't actually do anything....................
>
>
would make a handy door stop if nothing else
>>>Of course it does! Voice controlled, even:
>>>
>>>"Anne, turn the volume up a bit"......................
>>>
>>
>>Oh great, voice recognition software built in as well ...
>>
>>Does it ever go "I'm sorry Dave, I'm afraid I can't do that?"
>
>
> No, I have upgraded to the JCN 9000, which fixed those bugs.
>
>
JCN 9000?
Nousaine
Well it's easy to get reports of difference in open comparisons of equipment.
Even when you give subjects the same an identical sound presentations twice
it's common to have them report 'differences' about 3/4 of the time.
Further few will ever investigate those times that there are real audible
differences as to 'cause.' The largest cause of real difference is input
sensitivity. Give a power amp the same input voltage as another even relatively
small differences in input sensitivity will make audible loudness differences
at the speakers. Level matching is the level field enabling device.
Further I've encountered electronic stereo devices with balance mistracking as
high as 2-dB. It'svseldom the case where true cause is investigated even when
actual acoustic differences exist.
For example I once had a good friend who claimed his high-end amplifier sounded
clearly better than my old Parasound. In truth it actually did sound
"different" in a direct comparison but only because of input sensitivity
differences and a 2-dB channel imbalance in his reference piece. When I matched
levels channel to channel he was no longer tell them apart he wasn't able to
tell which one was driving his speakers.
I once assembled a 'highly-tweaked' system consisting of an outboard DAC,
vacumn tube pre-amp, high-end amp, $100/meter interconnects, $300 soeaker
cables with networks, special cable dress and Vibration control devices and not
one of 10 highly interested and deeply experienced hard core audiophiles was
able to reliably identify this system from a dumbed-down system including a
20-year old $99 kit preamplifier, a 10-year old used $200 Parasound power
amplifier, 'junk-box' interconnects, 16-guage car audio zip-cord speaker cables
with purposely "un-tweaked" cable dress (speaker cables of 6-feet for one
channel and 25-feet for the other with the 25-foot section wrapped around the
power cables) using their own programs, single listener sweet spot listening
with either system driving the same speakers ({PSB Stratus Mini.)
Of course, each of the systems were level matched channel to channel with each
other. There was no attempt at matching frequency response although it wasn't
necessary. What was most interesting is that there was a 2-dB channel imbalance
between the 2 systems when they were run 'naked.'
It is my opinion that most reported differences in sound quality among
pass-thru with gain electronics (pre-amps, equalizers in bypass mode, power
amplifiers, integrated amps and receivers with the tone controls bypassed or
centered) are the result of expectation (75% even when given the same sound
twice) and the rest are due to level/balance mismatches which may be more
common than commonly thought.
Tat Chan
> Georg Grosz wrote:
>
>> If the two preamps were given a fair double blind test, and sounded
>> different, one of them would probably be an incompetent design.
>
>
> I wish I had take more Philosophy classes that worked through logical
> thinking. Somehow when I make a post asking "Do preamps sound alike?"
> and there are a number of answers like this I imagine myself doing a
> comparison of two preamps, hearing a difference, then asking myself
> "Which one is the incompetent one. Let's check the specs. Hmmm, both
> have excellent specs. Could it be that both of them are incompetent in
> different ways?"
Dude, what else is a pre-amp meant to do other than act as a source
selector and volume control?
As such, a pre-amp should be nothing more than a connection (maybe with
some gain) to the power amp and as such have no distinct sound of its own.
Tat Chan
Whoops, I think I have answered my own question.
HAL --> IBM ---> JCN
Bob Marcus
> Georg Grosz wrote:
>
> > If the two preamps were given a fair double blind test, and sounded
> > different, one of them would probably be an incompetent design.
>
> I wish I had take more Philosophy classes that worked through logical
> thinking. Somehow when I make a post asking "Do preamps sound alike?"
> and there are a number of answers like this I imagine myself doing a
> comparison of two preamps, hearing a difference, then asking myself
> "Which one is the incompetent one.
The first question should be, "Have I listened to these in a way that
allows me to be SURE that I am really hearing a difference, and not
merely imagining one (or really hearing a dfference that's the result
of a level-mismatch, rather than any flaw in either unit)?" That's
probably your answer.
> Let's check the specs. Hmmm, both
> have excellent specs. Could it be that both of them are incompetent in
> different ways?"
Or could it be that the spec sheets do not accurately reflect each
component's performance?
> At that point to reach a conclusion I would either
> have to begin conducting technical research beyond my education or just
> deciding I like one better than the other, and start comparing it to
> others until I find the one I like best. At least I am qualified to do
> that. But then I have just thrown objectivity out the window. Or should
> I read audiophile magazines that have access to more preamps than I will
> ever be able to audition? No, can't do that they are subjective. But
> then so am I. Must be objective, but don't have the tools.
Sure you do. Anyone can do an objective listening comparison, if they
care to go to the trouble.
> I know,
> I'll post on RAHE. No, I did that and the results were definitely
> mixed. I must restart my train of thought as I seems to have acquired a
> circular track. Where is the exit?
>
The exit lies in learning to conduct meaningful listening comparisons.
Or in simply deciding to believe the subjectivists' story. Take your
pick.
bob
Ernst Raedecker
wrote:
>While I believe it is *very* important to understand the differences
>between "pre amp" and "passive line stage" to have an intelligent
>discussion on the topic, the two will probably evermore be used
>interchangeably. That is, the use of "passive" before "preamp", will
>probably be sufficient to distinguish one from the other.
The point is of course that when people speak of a "passive pre-amp",
they no longer refer to the amplification function of the "pre-amp",
but to the other functions pre-amps normally have, like volume control
and input source switching.
Ernesto.
"You don't have to learn science if you don't feel
like it. So you can forget the whole business if
it is too much mental strain, which it usually is."
Richard Feynman
B&D
<le_kin...@hotmail.com> wrote:
Hence the same goal for power amps, source components, speakers,
interconnects and even the media with recorded music itself -- all of it is
supposed to "get out of the way" and present the performance with no
coloration.
James Mitchell
> gain and buffering, and (b) the capacitance of the cable at the output
> could affect the frequency response.
Not only the cable capacitance. Many amplifiers use a shunt capacitor
(220pF, 390pF, etc) across the input to suppress high frequency noise. This
is very significant when using resistor values higher than 10KOhm.
Summitar
about an old Parasound preamp -- the PR200. Is it a John Curl design?
Is it as nice as the later Parasounds?
Also looking for info on the old Parasound PA260 Power amp... same
questions.
These models don´t even show up on the Parasound web site (which has
info on a lot of discontinued stuff.)
Robert C. Lang
.
> >
> >But your conclusions raises more questions (for me) they answer. If
> >there are no practical or measurable quality differences among
> >resistors what makes some passive sound better than others (and that
> >indeed has been my experience)?
>
> Has it indeed? Do you have any *evidence* for this extraordinary
> claim?
Please see comments in my post to this thread dated October 12
relative to my experiences with the Audible Illusions 3A.
>
> > I guess what I am asking is if key
> >parts such as resistors don't make a difference (I'm not trying to put
> >words in your mouth)
> >then what is the point of using anything but the cheapest?
>
> None at all, sonically. Of course, a P&G pot has a very smooth action
> and will last 'forever', as will the ruthenium-tipped relays.
Using parts that will increase the longevity and reliability of the
unit is as valid a reason as any for investing in more expensive
parts. Given that there are no sonic advantages in an high-end and
expensive line stage is the reliability factor the sole reason you
spent the extra bucks?
>
> >> That's certainly true, and can make some switched attenuators very
> >> expensive indeed.
> >
> >But will they sound better?
>
> Not in my experience, and I've built attenuators using Vishay S102s,
> which is as good as it gets technically.
Do expensive Vishay S102s (which is what my linestage utilizes) last
longer and or more reliable than the lower cost cousins? If not, why
pay the vastly increased cost?
Robert C. Lang
Chung
> Stewart Pinkerton <pat...@dircon.co.uk> wrote in message news:<cku91...@news3.newsguy.com>...
> .
>> >
>> >But your conclusions raises more questions (for me) they answer. If
>> >there are no practical or measurable quality differences among
>> >resistors what makes some passive sound better than others (and that
>> >indeed has been my experience)?
>>
>> Has it indeed? Do you have any *evidence* for this extraordinary
>> claim?
>
> Please see comments in my post to this thread dated October 12
> relative to my experiences with the Audible Illusions 3A.
What you posted was a sighted preference, hardly evidence. If you can
show that the Audible Illusions 3A has *measureably* better performance,
then you have something to start from. Even then, the better performance
could be due to better choice of resistor values, or a host of other
possibilities like better matching, better switching, etc., rather than
using expensive resistors vs not-so-expensive resistors
>
>>
>> > I guess what I am asking is if key
>> >parts such as resistors don't make a difference (I'm not trying to put
>> >words in your mouth)
>> >then what is the point of using anything but the cheapest?
>>
>> None at all, sonically. Of course, a P&G pot has a very smooth action
>> and will last 'forever', as will the ruthenium-tipped relays.
>
> Using parts that will increase the longevity and reliability of the
> unit is as valid a reason as any for investing in more expensive
> parts. Given that there are no sonic advantages in an high-end and
> expensive line stage is the reliability factor the sole reason you
> spent the extra bucks?
I think he likes the action of the P&G potentiometers. And perhaps the
much finer control (than resistive attenuators).
>
>>
>> >> That's certainly true, and can make some switched attenuators very
>> >> expensive indeed.
>> >
>> >But will they sound better?
>>
>> Not in my experience, and I've built attenuators using Vishay S102s,
>> which is as good as it gets technically.
>
> Do expensive Vishay S102s (which is what my linestage utilizes) last
> longer and or more reliable than the lower cost cousins? If not, why
> pay the vastly increased cost?
No reason to. The Vishay s102 family is designed for ultra-high accuracy
applications. It has excellent temperature stabililty and could be
ordered in matched pairs. Those are very good attributes for certain
applications like discrete DAC's, but overkill for audio applications.
Reliability/longevity is not a reason for using these expensive resistors.
I will be willing to bet that if you were to replace all the s102
resistors with cheaper metal film resistors of the same value, you could
not tell any difference.
Robert C. Lang
> Robert C. Lang wrote:
> > Stewart Pinkerton <pat...@dircon.co.uk> wrote in message news:<cku91...@news3.newsguy.com>...
> > .
> >> >
> >> >But your conclusions raises more questions (for me) they answer. If
> >> >there are no practical or measurable quality differences among
> >> >resistors what makes some passive sound better than others (and that
> >> >indeed has been my experience)?
> >>
> >> Has it indeed? Do you have any *evidence* for this extraordinary
> >> claim?
> >
> > Please see comments in my post to this thread dated October 12
> > relative to my experiences with the Audible Illusions 3A.
>
> What you posted was a sighted preference, hardly evidence. If you can
> show that the Audible Illusions 3A has *measureably* better performance,
> then you have something to start from. Even then, the better performance
> could be due to better choice of resistor values, or a host of other
> possibilities like better matching, better switching, etc., rather than
> using expensive resistors vs not-so-expensive resistors
>
>
I may be wrong but I *think* Stewart was questioning whether I had
evidence that I found some line stages to sound better or different
than other line stages, irrespective of the resistor issue. Because a
few posts ago after you and Stewart both presented compelling
empirical info about resistor measurements and performance I conceded
on that issue. That is, based on information presented there is no
basis to suggest that one resistor, no matter what the cost, will
perform or sound any different than another resistor.
That the Audible Illusions 3A sounded and performed "differently" in
my system than other line stages sounded and performed in my system is
a different matter altogether (I think). The question asked in the
thread is "Do all preamps sound alike"? It has been my experience,
that in my system. they don't all sound alike.
You suggest that because my audition of the Audible Illusion 3A was
sighted that my observations were not valid. (By the way, the
performance of the 3A was "less" not "better" in my system than other
line stages). I believe that if you read my comments closely that you
will find that the fact it was sighted had no affect on my
observation. I realize this is what they all say. But here it was
graphically black and white. No blind test required. Literally
hundreds of times I have listened to the Telarc Michael Murray
performance of the Poulenc Organ Concerto. Heading into the final 3
minutes or so the recording (and at a live performance) I habitually
brace myself for a faint but *very* deep organ passage which is
sustained continuously for well over 90 seconds. Because it is
sustained it is easier to gauge than a transient. Telarc says that
this sustained note was at 23 HZ. It feels like a small earthquake (I
live in the San Francisco Bay Area).
But with the Audible Illusions that sustained note simply did not
occur. It simply didn't happen. The faint groan of the organ didn't
happen, the *seemingly* change in the barometric pressure (for lack of
a better description) didn't happen, the very unique and easily
identifiable flutter of the floor didn't happen. Turning up the volume
to higher than normal did not make it happen. The bottom octave was
clearly rolled off.
I can't speak to *why* the lower octave was not reproduced. I offer
some opinions in my original comments and both the dealer and the
manufacturer confirmed that the unit was working to spec. Perhaps you
can shed some additional light on that. I can only say to an absolute
certainty that in *my* system (and that's all I am talking about) that
the lower octave was lacking with the 3A whereas as with most others
line stages it was not an issue. Up until that time I thought that
speakers were the limiting factor and that all pre amps sounded a like
(if not identical). I learned from that experience that other parts of
the chain can also get in the way.
Robert C. Lang
Uptown Audio
preamplify?
-Bill
www.uptownaudio.com
Roanoke VA
(540) 343-1250
"Tat Chan" <le_kin...@hotmail.com> wrote in message
news:ckvd7...@news4.newsguy.com...
Nousaine
If what you say is true than wouldn't you agree that these differences would be
completely revealed with a frequency response measurement taken at the input
terminals of the loudspeakers? Or even at the inputs to the power amplifier?
If you don't agree then when why not? After all humans only have 2 acoustical
inputs. The sound pressure on the ear drums and/or the sound pressure
transmitted through the body. When the signal delivered to the speaker inputs
isn't changed there is no way the speakers can figure out why they should
change their output.
As humans we can ONLY hear level differences (sound pressure) and arrival time
differences between our 2 ears. I'm wondering exactly how pre-amplifiers manage
to alter either when they are in a bypass mode.
Chung
Yes, and I think we were looking for evidence of said differences. What
you said is that you strongly believe that there are differences, but
that does not constitute evidence. Certainly others may not accept your
belief as evidence that such differences exist.
>
> That the Audible Illusions 3A sounded and performed "differently" in
> my system than other line stages sounded and performed in my system is
> a different matter altogether (I think). The question asked in the
> thread is "Do all preamps sound alike"? It has been my experience,
> that in my system. they don't all sound alike.
OK.
>
> You suggest that because my audition of the Audible Illusion 3A was
> sighted that my observations were not valid.
Your observations in that case are not evidence. You certainly are right
to choose your components based on your personal observations, though,
so they may be perfectly valid for you.
Definitely that difference, assuming it's real, is not caused by the
type (or price) of the resistors. I would guess that perhaps that unit
has a much lower input resistance, and that caused the output
capacitance of the source to have a high-pass cut-off that is too high
in frequency. Or that it has a coupling capacitor that is too small. Is
there transformer coupling inside the unit? Do you have a schematic of
the 3A?
On the manufacturer's website, the specs for the M3A say that the error
is +/- 1dB from 2 Hz to 100KHz for the high-level input. So that clearly
does not agree with what you observed. Were you using the phono section?
What you described can also be easily measured, if it was the high-level
input that you were using. In fact, you can probably measure it yourself
using a good voltmeter, if you have access to that unit. Play a test CD
disc with constant-level low frequency tones, and see how the output
level varies as you play different tones. It should be flat down to at
least 20 Hz. Make sure that you connect the outputs of the preamp to the
power amp while you make that measurement.
> I can only say to an absolute
> certainty that in *my* system (and that's all I am talking about) that
> the lower octave was lacking with the 3A whereas as with most others
> line stages it was not an issue. Up until that time I thought that
> speakers were the limiting factor and that all pre amps sounded a like
> (if not identical). I learned from that experience that other parts of
> the chain can also get in the way.
Sure, if the CD player, the preamp, or the power amp were poorly
implemented, then they can easily get in the way. But competence in
these components is easy to achieve today. That competence,
unfortunatly, cannot be assumed, particularly in the high-end products.
>
Stewart Pinkerton
wrote:
>Chung <chun...@covad.net> wrote in message news:<cl6sg...@news2.newsguy.com>...
>> Robert C. Lang wrote:
>> > Stewart Pinkerton <pat...@dircon.co.uk> wrote in message news:<cku91...@news3.newsguy.com>...
>> > .
>> >> >
>> >> >But your conclusions raises more questions (for me) they answer. If
>> >> >there are no practical or measurable quality differences among
>> >> >resistors what makes some passive sound better than others (and that
>> >> >indeed has been my experience)?
>> >>
>> >> Has it indeed? Do you have any *evidence* for this extraordinary
>> >> claim?
>> >
>> > Please see comments in my post to this thread dated October 12
>> > relative to my experiences with the Audible Illusions 3A.
>>
>> What you posted was a sighted preference, hardly evidence. If you can
>> show that the Audible Illusions 3A has *measureably* better performance,
>> then you have something to start from. Even then, the better performance
>> could be due to better choice of resistor values, or a host of other
>> possibilities like better matching, better switching, etc., rather than
>> using expensive resistors vs not-so-expensive resistors
>>
>I may be wrong but I *think* Stewart was questioning whether I had
>evidence that I found some line stages to sound better or different
>than other line stages, irrespective of the resistor issue.
On this point at least, you are not wrong. :-)
> Because a
>few posts ago after you and Stewart both presented compelling
>empirical info about resistor measurements and performance I conceded
>on that issue. That is, based on information presented there is no
>basis to suggest that one resistor, no matter what the cost, will
>perform or sound any different than another resistor.
Well, some types such as cracked carbon and simple wirewounds, do have
issues which may well cause audible problems, but otherwise no, I've
not found a $5 Vishay S102 to be audibly different than a 5 cent metal
film. I normally use Holco H4s or H8s, simply because they are of
immaculate build quality and reliability, and I acquired a bulk lot
many years ago.
>That the Audible Illusions 3A sounded and performed "differently" in
>my system than other line stages sounded and performed in my system is
>a different matter altogether (I think). The question asked in the
>thread is "Do all preamps sound alike"? It has been my experience,
>that in my system. they don't all sound alike.
Actually, that does raise the question of how you perceived this
'difference'. If under sighted conditions, then it's likely that your
perception was less than ideally accurate.
>You suggest that because my audition of the Audible Illusion 3A was
>sighted that my observations were not valid. (By the way, the
>performance of the 3A was "less" not "better" in my system than other
>line stages). I believe that if you read my comments closely that you
>will find that the fact it was sighted had no affect on my
>observation. I realize this is what they all say.
Quite so, hence you will understand my dismissal of your opinion.
> But here it was
>graphically black and white. No blind test required.
Yeah, right. That is indeed 'what they all say', usually right before
they can't tell any difference under level-matched DBT conditions...
> Literally
>hundreds of times I have listened to the Telarc Michael Murray
>performance of the Poulenc Organ Concerto. Heading into the final 3
>minutes or so the recording (and at a live performance) I habitually
>brace myself for a faint but *very* deep organ passage which is
>sustained continuously for well over 90 seconds. Because it is
>sustained it is easier to gauge than a transient. Telarc says that
>this sustained note was at 23 HZ. It feels like a small earthquake (I
>live in the San Francisco Bay Area).
>
>But with the Audible Illusions that sustained note simply did not
>occur. It simply didn't happen. The faint groan of the organ didn't
>happen, the *seemingly* change in the barometric pressure (for lack of
>a better description) didn't happen, the very unique and easily
>identifiable flutter of the floor didn't happen. Turning up the volume
>to higher than normal did not make it happen. The bottom octave was
>clearly rolled off.
That may of course be literally true. Have you measured the frequency
response of this generally well-regarded preamp?
>I can't speak to *why* the lower octave was not reproduced. I offer
>some opinions in my original comments and both the dealer and the
>manufacturer confirmed that the unit was working to spec. Perhaps you
>can shed some additional light on that. I can only say to an absolute
>certainty that in *my* system (and that's all I am talking about) that
>the lower octave was lacking with the 3A whereas as with most others
>line stages it was not an issue. Up until that time I thought that
>speakers were the limiting factor and that all pre amps sounded a like
>(if not identical). I learned from that experience that other parts of
>the chain can also get in the way.
So you say, but you offer no evidence that this perception had any
basis in the physical world.
Robert C. Lang
As pronounced as the bass frequency roll off was I would think it
would be readily measurable. If I suggested otherwise I certainly
didn't mean to.
> As humans we can ONLY hear level differences (sound pressure) and arrival time
> differences between our 2 ears. I'm wondering exactly how pre-amplifiers manage
> to alter either when they are in a bypass mode.
I don't know. Keep in mind that my observation of the bass roll off
did not involve transients that in music can be tricky, at best, to
compare lest you use a level matched A/B switch of some sort. On the
contrary the difference I observed were an organ bass note that was
sustained, continuously for 90 seconds. With the Audible Illusions
that 23 HZ note was completely missing for the entire 90 seconds. I
can only logically conclude that the Audible Illusions, in my system,
rolled off sharply below 30 HZ. What do you think acounts for such
audible, tactile (floor vibrations that did not occur as with other
line stages), and visual (lack of room vibrations as there are with
other line stages) differences?
Robert C. Lang
Robert C. Lang
I would guess that perhaps that unit
> has a much lower input resistance, and that caused the output
> capacitance of the source to have a high-pass cut-off that is too high
> in frequency. Or that it has a coupling capacitor that is too small. Is
> there transformer coupling inside the unit? Do you have a schematic of
> the 3A?
On the manufacturer's website, the specs for the M3A say that the
error
> is +/- 1dB from 2 Hz to 100KHz for the high-level input. So that clearly
> does not agree with what you observed. Were you using the phono section?
No. My observation was based primarily on the Telarc Poulenc Organ
Concerto CD.
>
> What you described can also be easily measured, if it was the high-level
> input that you were using. In fact, you can probably measure it yourself
> using a good voltmeter, if you have access to that unit. Play a test CD
> disc with constant-level low frequency tones, and see how the output
> level varies as you play different tones. It should be flat down to at
> least 20 Hz. Make sure that you connect the outputs of the preamp to the
> power amp while you make that measurement.
At my invitation Audible Illusion had every opportunity to make
measurements, while the pre amp was in my system as they are only 20
minutes away. They did not think it was necessary based on my
observations. By the way, the representatives of Audible Illusions
never doubted the validity of my observations (I have only used the
word "observation", never "evidence". Because as clearly stated in my
original comments (the ones made in February 2000 at
http://www.audioreview.com/Preamplifiers/Audible
Illusions/PRD_118448_1591crx.aspx#reviews) I had a strong bias in
favor of Audible Illusion because it is a local company and I had been
in direct contact with the company to arrange a purchase. Audible
Illusions took my observations and comments quite seriously and were
never cynical. They found my observations to be quite compelling (and
said so) because they involved more that just hearing (they also
involved sight [lamps not vibrating] and feel [vibration of floor].
Audible Illusions offered an explanation that I retrieved from the
archives of this group I made several years back.
To put the Audible Illusion representative's comments in perspective
it should be noted that my system is bi-amped.
"The day after I wrote my comments Art Ferris, of Audible
Illusions, in a email to me expressed his belief that because
I was "driving several amplifiers, electronic crossover
etc." he believed that the "paralleled load impedance" of my
amplifiers was well below the minimum load impedance of 20kohm.
Mr. Ferris also expressed concern whether I was "running low
capacitance interconnect recommended for use with the
Audible Illusion 3A. He expressed that high capacitance
interconnects could account for bass roll-off.
Mr. Ferriss also stated that "in most normal systems", where
the pre amp is driving an amplifier with an input impedance
above 20kohm, I would not experience a problem."
>
>
> > I can only say to an absolute
> > certainty that in *my* system (and that's all I am talking about) that
> > the lower octave was lacking with the 3A whereas as with most others
> > line stages it was not an issue. Up until that time I thought that
> > speakers were the limiting factor and that all pre amps sounded a like
> > (if not identical). I learned from that experience that other parts of
> > the chain can also get in the way.
>
> Sure, if the CD player, the preamp, or the power amp were poorly
> implemented, then they can easily get in the way. But competence in
> these components is easy to achieve today. That competence,
> unfortunatly, cannot be assumed, particularly in the high-end products.
Agreed. But also that even competently designed gear such as the
Audible Illusion 3A is not always a fit in all systems.
Robert C. Lang
Jim
news:cldqv...@news3.newsguy.com:
>
> Mr. Ferris also expressed concern whether I was "running low
> capacitance interconnect recommended for use with the
> Audible Illusion 3A. He expressed that high capacitance
> interconnects could account for bass roll-off.
>
Mr. Ferris is blowing smoke on this one. High capacitance interconnects
might affect the high end, but certainly not low frequencies.
-- JS
Stewart Pinkerton
wrote:
>nous...@aol.com (Nousaine) wrote in message news:<cl9tm...@news2.newsguy.com>...
>> As humans we can ONLY hear level differences (sound pressure) and arrival time
>> differences between our 2 ears. I'm wondering exactly how pre-amplifiers manage
>> to alter either when they are in a bypass mode.
>
>I don't know. Keep in mind that my observation of the bass roll off
>did not involve transients that in music can be tricky, at best, to
>compare lest you use a level matched A/B switch of some sort. On the
>contrary the difference I observed were an organ bass note that was
>sustained, continuously for 90 seconds. With the Audible Illusions
>that 23 HZ note was completely missing for the entire 90 seconds. I
>can only logically conclude that the Audible Illusions, in my system,
>rolled off sharply below 30 HZ. What do you think acounts for such
>audible, tactile (floor vibrations that did not occur as with other
>line stages), and visual (lack of room vibrations as there are with
>other line stages) differences?
What you report is shall we say, vanishingly unlikely, unless there
was something *seriously* wrong with your system. Bear in mind that
the 3A is specified as flat to -1dB down to 2Hz, and you'll see that
what you are reporting is essentially impossible. BTW, it's worth
remembering that, while John Curl is a talented and professional
designer, Art Ferris is a graphic artist turned 'high end' audio
salesman, so not to be relied on for anything technical! :-)
Stewart Pinkerton
wrote:
>To put the Audible Illusion representative's comments in perspective
>it should be noted that my system is bi-amped.
>
>"The day after I wrote my comments Art Ferris, of Audible
>Illusions, in a email to me expressed his belief that because
>I was "driving several amplifiers, electronic crossover
>etc." he believed that the "paralleled load impedance" of my
>amplifiers was well below the minimum load impedance of 20kohm.
An active crossover will not in general present a lower load impedance
than would a power amplifier. The power amps are of course *not*
directly connected to the preamp in such a situation, hence there is
no question of any 'paralleled load impedance'. From your comments, It
sounds like Art Ferris is utterly incompetent.
>Mr. Ferris also expressed concern whether I was "running low
>capacitance interconnect recommended for use with the
>Audible Illusion 3A. He expressed that high capacitance
>interconnects could account for bass roll-off.
>
>Mr. Ferriss also stated that "in most normal systems", where
>the pre amp is driving an amplifier with an input impedance
>above 20kohm, I would not experience a problem."
This is utter rubbish. The only possible effects due to high
capacitance interconnects would occur in the extreme treble. It is
simply not possible for cable capacitance and/or low load impedance to
make a difference to the bass.
>> > I can only say to an absolute
>> > certainty that in *my* system (and that's all I am talking about) that
>> > the lower octave was lacking with the 3A whereas as with most others
>> > line stages it was not an issue. Up until that time I thought that
>> > speakers were the limiting factor and that all pre amps sounded a like
>> > (if not identical). I learned from that experience that other parts of
>> > the chain can also get in the way.
>>
>> Sure, if the CD player, the preamp, or the power amp were poorly
>> implemented, then they can easily get in the way. But competence in
>> these components is easy to achieve today. That competence,
>> unfortunatly, cannot be assumed, particularly in the high-end products.
>
>Agreed. But also that even competently designed gear such as the
>Audible Illusion 3A is not always a fit in all systems.
However, what you report is simply not technically possible.
Chung
> Chung <chun...@covad.net> wrote in message >
>
> I would guess that perhaps that unit
>> has a much lower input resistance, and that caused the output
>> capacitance of the source to have a high-pass cut-off that is too high
>> in frequency. Or that it has a coupling capacitor that is too small. Is
>> there transformer coupling inside the unit? Do you have a schematic of
>> the 3A?
>
>
> On the manufacturer's website, the specs for the M3A say that the
> error
>> is +/- 1dB from 2 Hz to 100KHz for the high-level input. So that clearly
>> does not agree with what you observed. Were you using the phono section?
>
> No. My observation was based primarily on the Telarc Poulenc Organ
> Concerto CD.
In that case, there is a huge discrepancy between your observations and
the spec sheet.
>>
>> What you described can also be easily measured, if it was the high-level
>> input that you were using. In fact, you can probably measure it yourself
>> using a good voltmeter, if you have access to that unit. Play a test CD
>> disc with constant-level low frequency tones, and see how the output
>> level varies as you play different tones. It should be flat down to at
>> least 20 Hz. Make sure that you connect the outputs of the preamp to the
>> power amp while you make that measurement.
>
> At my invitation Audible Illusion had every opportunity to make
> measurements, while the pre amp was in my system as they are only 20
> minutes away. They did not think it was necessary based on my
> observations. By the way, the representatives of Audible Illusions
> never doubted the validity of my observations (I have only used the
> word "observation", never "evidence". Because as clearly stated in my
> original comments (the ones made in February 2000 at
> http://www.audioreview.com/Preamplifiers/Audible
> Illusions/PRD_118448_1591crx.aspx#reviews) I had a strong bias in
> favor of Audible Illusion because it is a local company and I had been
> in direct contact with the company to arrange a purchase. Audible
> Illusions took my observations and comments quite seriously and were
> never cynical. They found my observations to be quite compelling (and
> said so) because they involved more that just hearing (they also
> involved sight [lamps not vibrating] and feel [vibration of floor].
> Audible Illusions offered an explanation that I retrieved from the
> archives of this group I made several years back.
How could they have taken your comments seriously if they did not try to
get to the cause of the problem? Or give you a replacement first?
>
> To put the Audible Illusion representative's comments in perspective
> it should be noted that my system is bi-amped.
>
> "The day after I wrote my comments Art Ferris, of Audible
> Illusions, in a email to me expressed his belief that because
> I was "driving several amplifiers, electronic crossover
> etc." he believed that the "paralleled load impedance" of my
> amplifiers was well below the minimum load impedance of 20kohm.
I would think that your electronic crossover is in *series* with the
power amp, so that the preamp only sees the crossover as a load. Does
your crossover has an extremely low input impedance, like less than 10K?
>
> Mr. Ferris also expressed concern whether I was "running low
> capacitance interconnect recommended for use with the
> Audible Illusion 3A. He expressed that high capacitance
> interconnects could account for bass roll-off.
Mr. Ferris is clearly technically incompetent. You can ignore everything
he said, based on that comment.
>
> Mr. Ferriss also stated that "in most normal systems", where
> the pre amp is driving an amplifier with an input impedance
> above 20kohm, I would not experience a problem."
Assuming that the +/- 1dB spec at 2Hz is achieved at 50K loading as
stated in the specs, it would take a load of 5K to move the -1dB point
to 20 Hz, if the output coupling capacitor was causing the roll-off. (If
some interstage cap or transformer was casuing the roll-off, then output
loading should not make any difference.) And even that still does not
account for your observations, which were more like -6dB or worse at 23 Hz.
Seems like you had a defective M3A.
B&D
<chun...@covad.net> wrote:
>> Mr. Ferris also expressed concern whether I was "running low
>> capacitance interconnect recommended for use with the
>> Audible Illusion 3A. He expressed that high capacitance
>> interconnects could account for bass roll-off.
>
> Mr. Ferris is clearly technically incompetent. You can ignore everything
> he said, based on that comment.
Wow - that is a rather sweeping statement, Chung. Before passing judgement
on someone else (It certainly seems we are all very quick to come to the
conclusions like the ones you did) might be good to dig a little deeper, eh?
Robert C. Lang
> On 21 Oct 2004 23:41:06 GMT, lan...@pacbell.net (Robert C. Lang)
> wrote:
>
> >Chung <chun...@covad.net> wrote in message news:<cl6sg...@news2.newsguy.com>...
> >> Robert C. Lang wrote:
> >> > Stewart Pinkerton <pat...@dircon.co.uk> wrote in message news:<cku91...@news3.newsguy.com>...
>
>
>
> >You suggest that because my audition of the Audible Illusion 3A was
> >sighted that my observations were not valid. (By the way, the
> >performance of the 3A was "less" not "better" in my system than other
> >line stages). I believe that if you read my comments closely that you
> >will find that the fact it was sighted had no affect on my
> >observation. I realize this is what they all say.
>
> Quite so, hence you will understand my dismissal of your opinion.
First, it doesn't matter. Audible Illusions (including at least two
engineers in the company) found my observations to be dispassionate
and plausible not to require measurements or dbts to confirm the
obvious. Audible Illusions (only 20 minutes away) had the opportunity
to make measurements; they chose not to. They came to the same
conclusions I did. That is, that there *was* an audible bass roll off
of the 3A in *my* system (not necessarily applicable to your system).
Second, with respect to your remarkable propensity to curtly dismiss
others opinions and require corroborative proof for such, by English
definition *opinion* "is a belief or conclusion held with confidence,
but not substantiated by positive knowledge or proof". Opinions are by
*definition* unsubstantiated! This definition should be familiar to
you because I have offered to you on several occasions in the past.
I have never asked you to substantiate with measurements or with any
other form of "evidence" your *opinion* on XRCDs or CD players,
speakers, or anything else. It would be not only disingenious, but
also unfair to you and to the discussion. Indeed, at times your
pronouncements are validated only by the fervor with which you offer
them. For example, this past January 21 I mentioned to the group (not
you in particular) that I was considering several universal players.
You exhorted "Pioneer DV-868 - accept no substitute!"
The exchange went like this:
I'm attending CES specifically to narrow my choices
>for a universal player so I can listen to DVD-A as well as SACD and
CD.
>Pioneer DV-868 - accept no substitute! :-)
And then when I asked for even a low-level clarification on one of
your endorsements you didn't respond. No problem there, but I would
hope that you would refrain from holding others to standards that you
yourself don't adhere to.
Robert C. Lang
--------------------------------------------------------------------------------
Robert C. Lang
Frankly, That was my thinking at the time.
Robert C. Lang
Robert C. Lang
How about something being "wrong" with the Audible Illusions? Or how
about nothing being wrong with the Audible Illusions but it just
innocently rolled off below 30 hz? Because, roll off notwithstanding
the 3A did sound good. And if something is "wrong" with my system you
care to offer your opinion as to what are the possibilities?
Particularly, since the problem (lack of below 30 hz bass) has not
been audibly evident with other line stages.
Also, you have been quiet vocal in dissing the accuracy of tube gear.
What in you opinion, if any, might that have contributed to the 3A
performance?
And as for the competence of Mr. Ferris, I'm not about to touch that
one, except he did collaborate with others at Audible Illusions
including engineers. Indeed, I had discussions with Mr. Ferris, and
two engineers. Although I agreed with their conclusion, I did not
"buy" their explanation.
Robert C. Lang
Stewart Pinkerton
>Stewart Pinkerton <pat...@dircon.co.uk> wrote in message news:<ckpmf...@news2.newsguy.com>...
>> On 15 Oct 2004 03:30:40 GMT, B&D <br...@ix.netcom.com> wrote:
>>
>> >I have a question - given the dynamic range of live music (I have no idea
>> >what that might be) - is it possible to record it faithfully on CD or other
>> >media without at least some compression?
>>
>> Yes. There is no known master tape with a dynamic range of greater
>> than 80-85 dB
>
>But the question wasn't whether a CD could capture the dynamic range
>of an extant master tape, but whether it could capture the dynamic
>range of a live performance.
Let me rephrase that. Modern 24-bit digital mastering has a true
dynamic range of around 110dB, but even the most dynamic studio
recordings do not exceed 80dB at the very most. I'm not aware of any
live concert recording which exceeds 70dB, because while the peak SPLs
in the front stalls may reach 105-110dB for the grandest symphonic
works, the noise floor in the hall is never less than 40dB, even in
that moment of relative hush when the conductor first raises his
baton.
>> In fact, most live performances will have a dynamic
>> range of about 60-70dB, as the noise floor in a concert hall will
>> never be lower than 40dB or so.
>
>You've never heard music beneath the noise floor in a recording? Or
>beneath the noise floor in a concert hall?
Sure, and you can do exactly the same with CD. I've recorded tones at
-110dB on a CD-R which were clearly audible. That's what dithering
*does*, but it does not affect the definition of dynamic range, which
is from peak level to broadband noise floor.
>Yes, given the dynamic range of MOST live music, 16 bit/44.1k PCM is
>an adequate recording medium.
No, *all* live music.
> And those very few exceptions would
>probably be pointless to attempt to store in any medium that exceeds
>redbook CD's dynamic range because they would tax the limitations of
>the playback equipment...or of the listener's ears.
AFAIK, there are no such exceptions - unless you can produce a
recording of such an event.
Robert C. Lang
I can't respond to what else you have written above, but I agree it
has always been my understanding that high capacitance interconnects
would could possible only effect the extreme treble, especially with a
passive line stage.
>
> >> > I can only say to an absolute
> >> > certainty that in *my* system (and that's all I am talking about) that
> >> > the lower octave was lacking with the 3A whereas as with most others
> >> > line stages it was not an issue. Up until that time I thought that
> >> > speakers were the limiting factor and that all pre amps sounded a like
> >> > (if not identical). I learned from that experience that other parts of
> >> > the chain can also get in the way.
> >>
> >> Sure, if the CD player, the preamp, or the power amp were poorly
> >> implemented, then they can easily get in the way. But competence in
> >> these components is easy to achieve today. That competence,
> >> unfortunatly, cannot be assumed, particularly in the high-end products.
> >
> >Agreed. But also that even competently designed gear such as the
> >Audible Illusion 3A is not always a fit in all systems.
>
> However, what you report is simply not technically possible.
So that I may further understand what you are talking about, what
*specifically* is not technically possible?
Robert C. Lang
Stewart Pinkerton
You need dig no deeper than that blatantly erroneous statement by
Ferris. If you were to dig deeper, you'd find that Ferris trained as a
graphic artist, then moved into *selling* high-end audio. Technical
credentials - zero. Judging by his statements quoted in this thread,
technical knowledge also zero....................
Jim
- Was the subsonic filter enabled?
- Is the switch for this function defective?
Normally, I'd expect the subsonic filter to be applicable to the phono
stage only, but since specs for the 3A available on the web don't give much
information, who knows how it's implemented.
Bob Marcus
> error
> > is +/- 1dB from 2 Hz to 100KHz for the high-level input. So that clearly
> > does not agree with what you observed. Were you using the phono section?
>
> No. My observation was based primarily on the Telarc Poulenc Organ
> Concerto CD.
Well, it looks as if either your observation or the spec sheet was
wrong. Spec sheets can be wrong.
<snip>
>
> "The day after I wrote my comments Art Ferris, of Audible
> Illusions, in a email to me expressed his belief that because
> I was "driving several amplifiers, electronic crossover
> etc." he believed that the "paralleled load impedance" of my
> amplifiers was well below the minimum load impedance of 20kohm.
>
> Mr. Ferris also expressed concern whether I was "running low
> capacitance interconnect recommended for use with the
> Audible Illusion 3A. He expressed that high capacitance
> interconnects could account for bass roll-off.
>
> Mr. Ferriss also stated that "in most normal systems", where
> the pre amp is driving an amplifier with an input impedance
> above 20kohm, I would not experience a problem."
I gather you did not test this assertion by trying the preamp with a
different amplifier. Pity.
> >
> > > I can only say to an absolute
> > > certainty that in *my* system (and that's all I am talking about) that
> > > the lower octave was lacking with the 3A whereas as with most others
> > > line stages it was not an issue. Up until that time I thought that
> > > speakers were the limiting factor and that all pre amps sounded a like
> > > (if not identical).
Just for the record, no one's ever claimed that all preamps sound
alike.
> > > I learned from that experience that other parts of
> > > the chain can also get in the way.
> >
> > Sure, if the CD player, the preamp, or the power amp were poorly
> > implemented, then they can easily get in the way. But competence in
> > these components is easy to achieve today. That competence,
> > unfortunatly, cannot be assumed, particularly in the high-end products.
>
> Agreed. But also that even competently designed gear such as the
> Audible Illusion 3A is not always a fit in all systems.
Perhaps we should be open to the possibility that this is NOT
competently designed gear. We should certainly be open to the
possibility that this was defective gear. And we certainly cannot
conclude from your experience that preamps will in general sound
different (barring defects or incompetent design).
bob
Chung
So would you trust anything Mr. Ferris said regarding this problem? Or
do you need to dig deeper before you can dismiss his comment that high
capacitance interconnects could cause bass roll-offs?
normanstrong
I gather that this is a passive "preamp". If so, it should not have
a low frequency limit--unless there is a coupling capacitor somewhere
in the circuit. If this capacitor is at the input, I can see no way
that it can screw up the low frequency response, since the load
impedance is known by the manufacturer. However, if it's at the
output, the load is unknown, and if you have several parallel loads,
it could move the pole up to where 23 Hz is down quite a bit. IMHO
this would be a bad design choice, but stranger things have happened.
You might try disconnecting as many devices as you can, and then see
if the bass improves. Of course if you have a voltmeter and a stable
frequency source, you can answer the question at once.
Norm Strong
Stewart Pinkerton
wrote:
There's nothing 'innocent' about a component specified as flat to 2Hz,
rolling off at 30Hz!
> Because, roll off notwithstanding
>the 3A did sound good. And if something is "wrong" with my system you
>care to offer your opinion as to what are the possibilities?
>Particularly, since the problem (lack of below 30 hz bass) has not
>been audibly evident with other line stages.
Your imagination seems to be the most likely culprit.
>Also, you have been quiet vocal in dissing the accuracy of tube gear.
>What in you opinion, if any, might that have contributed to the 3A
>performance?
It's hard to be quiet vocal, but I have in point of fact never had a
problem with tubed preamps, aside from phono stages, where noise is an
inevitable problem. Indeed, tubed preamps have excellent overload
capacity, and are generally nicely linear. Unnecessarily expensive to
be sure, when compared with SS, but not audibly problematical.
>And as for the competence of Mr. Ferris, I'm not about to touch that
>one, except he did collaborate with others at Audible Illusions
>including engineers. Indeed, I had discussions with Mr. Ferris, and
>two engineers. Although I agreed with their conclusion, I did not
>"buy" their explanation.
You should not have agreed with their conclusion, as it is technically
impossible.
Stewart Pinkerton
wrote:
That high-capacitance cables, or low load impedance, could affect the
bass.
B&D
Pinkerton" <pat...@dircon.co.uk> wrote:
>> But the question wasn't whether a CD could capture the dynamic range
>> of an extant master tape, but whether it could capture the dynamic
>> range of a live performance.
>
> Let me rephrase that. Modern 24-bit digital mastering has a true
> dynamic range of around 110dB, but even the most dynamic studio
> recordings do not exceed 80dB at the very most. I'm not aware of any
> live concert recording which exceeds 70dB, because while the peak SPLs
> in the front stalls may reach 105-110dB for the grandest symphonic
> works, the noise floor in the hall is never less than 40dB, even in
> that moment of relative hush when the conductor first raises his
> baton.
This is a bit off topic, but wanted to ask the group:
Interesting thing - I talked with someone who was talking about periodic
signals vs. true white noise - people can detect a periodic signal a bit
into the absolute noise floor (kind of like how you can "hear" a morse code
feed even though it is a bit below the noise floor, but not be able to make
out the tone itself).
I am speculating here - but would the type of noise floor matter in the
general niceness of the sound itself?
For instance, if I put a square wave or triangle wave at 40dB below the peak
of an orchestra, and the followed it up with white noise at the same rms
power level - would one sound better than the other?
It occurred to me when I was listening to a Susan McCorkle CD when she sings
"The Waters of March" and the percussionist uses the brush on the cymbal
making the very white noise-like background - which is pleasant when one is
listening to a voice.
Stewart Pinkerton
wrote:
They sound like classic 'high end' clowns with no technical expertise
(or indeed *interest*) whatever. Did they not *care* that a purchaser
was supposedly experiencing severe difficulties with their equipment?
>Second, with respect to your remarkable propensity to curtly dismiss
>others opinions and require corroborative proof for such, by English
>definition *opinion* "is a belief or conclusion held with confidence,
>but not substantiated by positive knowledge or proof". Opinions are by
>*definition* unsubstantiated! This definition should be familiar to
>you because I have offered to you on several occasions in the past.
So, you admit that this 'lack of bass' is simply an opinion, and need
not have any substance in the real physical world?
>I have never asked you to substantiate with measurements or with any
>other form of "evidence" your *opinion* on XRCDs or CD players,
>speakers, or anything else. It would be not only disingenious, but
>also unfair to you and to the discussion.
Not at all, I am always happy to explain my preferences.
> Indeed, at times your
>pronouncements are validated only by the fervor with which you offer
>them. For example, this past January 21 I mentioned to the group (not
>you in particular) that I was considering several universal players.
>You exhorted "Pioneer DV-868 - accept no substitute!"
At the moment, I hold the same opinion.
>The exchange went like this:
>
>I'm attending CES specifically to narrow my choices
>>for a universal player so I can listen to DVD-A as well as SACD and
>CD.
>
>>Pioneer DV-868 - accept no substitute! :-)
>
>And then when I asked for even a low-level clarification on one of
>your endorsements you didn't respond. No problem there, but I would
>hope that you would refrain from holding others to standards that you
>yourself don't adhere to.
Excuse me? What 'clarification' did you request? I am always happy to
explain my 'endorsements'. Perhaps you phrased your request oddly -
quelle surprise.........................
B&D
Lang" <lan...@pacbell.net> wrote:
> How about something being "wrong" with the Audible Illusions? Or how
> about nothing being wrong with the Audible Illusions but it just
> innocently rolled off below 30 hz? Because, roll off notwithstanding
> the 3A did sound good. And if something is "wrong" with my system you
> care to offer your opinion as to what are the possibilities?
> Particularly, since the problem (lack of below 30 hz bass) has not
> been audibly evident with other line stages.
Either the spec is incorrect, or there is abuild defect in the AI unit -
like a series capacitor between stages or after the last stage has a value
that might be too high - or that the output series capacitor is driving the
equivalent of a shunt inductor in your system which would tune the high pass
response?
Chung
Uhh, if the series capacitor has too high a value, it will give an even
*lower* -3dB frequency.
A coupling capacitor at the output that is too low can explain what was
observed, assuming the observations were accurate. It would take a very
incompetent engineer to pick the wrong value, though.
BTW, I know of no crossover network or amplifier that has a shunt
inductor at the input sufficiently high to affect the bass response.
Assuming a coupling cap of 10 uF. It will take a shunt inductor of 6.33
henries (!) to resonate at 20 Hz.
B&D
<chun...@covad.net> wrote:
>> Either the spec is incorrect, or there is abuild defect in the AI unit -
>> like a series capacitor between stages or after the last stage has a value
>> that might be too high - or that the output series capacitor is driving the
>> equivalent of a shunt inductor in your system which would tune the high pass
>> response?
>
>
> Uhh, if the series capacitor has too high a value, it will give an even
> *lower* -3dB frequency.
Meaning the impedance magnitude (Z = 1/jwC), not the # of Farads.
Chung
> On 10/24/04 11:22 AM, in article clghb...@news4.newsguy.com, "Stewart
> Pinkerton" <pat...@dircon.co.uk> wrote:
>
>>> But the question wasn't whether a CD could capture the dynamic range
>>> of an extant master tape, but whether it could capture the dynamic
>>> range of a live performance.
>>
>> Let me rephrase that. Modern 24-bit digital mastering has a true
>> dynamic range of around 110dB, but even the most dynamic studio
>> recordings do not exceed 80dB at the very most. I'm not aware of any
>> live concert recording which exceeds 70dB, because while the peak SPLs
>> in the front stalls may reach 105-110dB for the grandest symphonic
>> works, the noise floor in the hall is never less than 40dB, even in
>> that moment of relative hush when the conductor first raises his
>> baton.
>
> This is a bit off topic, but wanted to ask the group:
>
> Interesting thing - I talked with someone who was talking about periodic
> signals vs. true white noise - people can detect a periodic signal a bit
> into the absolute noise floor (kind of like how you can "hear" a morse code
> feed even though it is a bit below the noise floor, but not be able to make
> out the tone itself).
A tone can be detected even if it's below the noise floor. You can do
enough averaging (filtering) to recover it.
>
> I am speculating here - but would the type of noise floor matter in the
> general niceness of the sound itself?
>
> For instance, if I put a square wave or triangle wave at 40dB below the peak
> of an orchestra, and the followed it up with white noise at the same rms
> power level - would one sound better than the other?
Well, what do you think?
In one case you have a tone, and in the other you have white noise. You
want to always hear a tone when you music is playing?
Steven Sullivan
> No, *all* live music.
Everest's 'Fundamentals of Acoustics' retains in its current (4th ) edition
a figure from previous editions, (Fig 5-12 in the 4th) derived from a
1982 study by Fiedler of the dynamic range of live 'classical' concert music.
This shows a maximum range of 118dB for close-mic'd percussive symphonic
music, and 113 dB for typical symphonic music without an audience (micing conditions
not stated, but presumably not close-mic'd). Everest describes the this as follows:
"Fiedler's study has shown that a dynamic range of up to 118dB is necessary
for subjectively noise-free reproduction of music. He considered the
peak instantaneous sound level of various sources ... and the just-audible
threshold for white noise added to the program source whent he listener is
in the normal listening situation. He used musical perforamcnes of high
peak levesl in ta quiet environment and a very simple recording setup.
...the signal to noise ration offered by a16-bit PCM system is shown to be
inadequate for all but piano solo. Future developments will undoubtedly
require greater dynamic range than that offered by 16-bit digita;l
systems.'
So, leaving aside the prevalence of >16-bit recording setups these days,
has Everest misinterpreted Fiedler's data or is there another dimension
to the story?
(Fiedler LD . 1982. Dynamic range requirements for subjectively noise-free
reproduction of music . J Aud Eng Soc, 30:, 7/8, 504-511.)
Robert C. Lang
Agreed.
Robert C. Lang
Stewart Pinkerton
It has often been suggested that such a background mask is one of the
reasons why some listeners prefer vinyl to CD, and also why some
recording engineers prefer hissy analogue tape to the inky blackness
of digital.
Nousaine
>nous...@aol.com (Nousaine) wrote in message
>news:<cl9tm...@news2.newsguy.com>...
>> lan...@pacbell.net (Robert C. Lang) wrote:
>>
>>
>>
>> >
>> >Chung <chun...@covad.net> wrote in message
>> >news:<cl6sg...@news2.newsguy.com>...
>> >> Robert C. Lang wrote:
>> >> > Stewart Pinkerton <pat...@dircon.co.uk> wrote in message
>> news:<cku91...@news3.newsguy.com>...
>> >> > .
>> >> >> >
>> >> >> >But your conclusions raises more questions (for me) they answer. If
>> >> >> >there are no practical or measurable quality differences among
>> >> >> >resistors what makes some passive sound better than others (and that
>> >> >> >indeed has been my experience)?
>> >> >>
>> >> >> Has it indeed? Do you have any *evidence* for this extraordinary
>> >> >> claim?
>> >> >
>> >> > Please see comments in my post to this thread dated October 12
>> >> > relative to my experiences with the Audible Illusions 3A.
>> >>
>> >> What you posted was a sighted preference, hardly evidence. If you can
>> >> show that the Audible Illusions 3A has *measureably* better performance,
>
>> >> then you have something to start from. Even then, the better performance
>
>> >> could be due to better choice of resistor values, or a host of other
>> >> possibilities like better matching, better switching, etc., rather than
>> >> using expensive resistors vs not-so-expensive resistors
>> >>
>> >>
>> >
>> >I may be wrong but I *think* Stewart was questioning whether I had
>> >evidence that I found some line stages to sound better or different
>> >than other line stages, irrespective of the resistor issue. Because a
>> >few posts ago after you and Stewart both presented compelling
>> >empirical info about resistor measurements and performance I conceded
>> >on that issue. That is, based on information presented there is no
>> >basis to suggest that one resistor, no matter what the cost, will
>> >perform or sound any different than another resistor.
>> >
>> >That the Audible Illusions 3A sounded and performed "differently" in
>> >my system than other line stages sounded and performed in my system is
>> >a different matter altogether (I think). The question asked in the
>> >thread is "Do all preamps sound alike"? It has been my experience,
>> >that in my system. they don't all sound alike.
>> >
>> >You suggest that because my audition of the Audible Illusion 3A was
>> >sighted that my observations were not valid. (By the way, the
>> >performance of the 3A was "less" not "better" in my system than other
>> >line stages). I believe that if you read my comments closely that you
>> >will find that the fact it was sighted had no affect on my
>> >observation. I realize this is what they all say. But here it was
>> >graphically black and white. No blind test required. Literally
>> >hundreds of times I have listened to the Telarc Michael Murray
>> >performance of the Poulenc Organ Concerto. Heading into the final 3
>> >minutes or so the recording (and at a live performance) I habitually
>> >brace myself for a faint but *very* deep organ passage which is
>> >sustained continuously for well over 90 seconds. Because it is
>> >sustained it is easier to gauge than a transient. Telarc says that
>> >this sustained note was at 23 HZ. It feels like a small earthquake (I
>> >live in the San Francisco Bay Area).
>> >
>> >But with the Audible Illusions that sustained note simply did not
>> >occur. It simply didn't happen. The faint groan of the organ didn't
>> >happen, the *seemingly* change in the barometric pressure (for lack of
>> >a better description) didn't happen, the very unique and easily
>> >identifiable flutter of the floor didn't happen. Turning up the volume
>> >to higher than normal did not make it happen. The bottom octave was
>> >clearly rolled off.
>> >
>> >I can't speak to *why* the lower octave was not reproduced. I offer
>> >some opinions in my original comments and both the dealer and the
>> >manufacturer confirmed that the unit was working to spec. Perhaps you
>> >can shed some additional light on that. I can only say to an absolute
>> >certainty that in *my* system (and that's all I am talking about) that
>> >the lower octave was lacking with the 3A whereas as with most others
>> >line stages it was not an issue. Up until that time I thought that
>> >speakers were the limiting factor and that all pre amps sounded a like
>> >(if not identical). I learned from that experience that other parts of
>> >the chain can also get in the way.
>> >
>> >Robert C. Lang
>>
>> If what you say is true than wouldn't you agree that these differences
>would be
>> completely revealed with a frequency response measurement taken at the
>input
>> terminals of the loudspeakers? Or even at the inputs to the power
>amplifier?
>
>As pronounced as the bass frequency roll off was I would think it
>would be readily measurable. If I suggested otherwise I certainly
>didn't mean to.
>
>
>> As humans we can ONLY hear level differences (sound pressure) and arrival
>time
>> differences between our 2 ears. I'm wondering exactly how pre-amplifiers
>manage
>> to alter either when they are in a bypass mode.
>
>I don't know. Keep in mind that my observation of the bass roll off
>did not involve transients that in music can be tricky, at best, to
>compare lest you use a level matched A/B switch of some sort. On the
>contrary the difference I observed were an organ bass note that was
>sustained, continuously for 90 seconds. With the Audible Illusions
>that 23 HZ note was completely missing for the entire 90 seconds. I
>can only logically conclude that the Audible Illusions, in my system,
>rolled off sharply below 30 HZ. What do you think acounts for such
>audible, tactile (floor vibrations that did not occur as with other
>line stages), and visual (lack of room vibrations as there are with
>other line stages) differences?
>
>Robert C. Lang
Poor design or ineffective operation. IOW it uses a high pass filter at an
unacceptably high frequency or it was broke.
Stewart Pinkerton
wrote:
Actually, it's an active tubed unit, but specified as flat to 2Hz, and
measured as flat to below 10Hz by Stereophile.
>You might try disconnecting as many devices as you can, and then see
>if the bass improves. Of course if you have a voltmeter and a stable
>frequency source, you can answer the question at once.
But according to the OP, he uses an active crossover, so he does *not*
have a low load on this preamp.
Robert C. Lang
> Just for the record, no one's ever claimed that all preamps sound
> alike.
> Perhaps we should be open to the possibility that this is NOT
> competently designed gear. We should certainly be open to the
> possibility that this was defective gear. And we certainly cannot
> conclude from your experience that preamps will in general sound
> different (barring defects or incompetent design).
>
> bob
Or that I made an error somewhere along the line during hook up or
something.
Having said that it is my opinion that any given component can peform
and sound differently in a given system. I believe my experience with
the Audible Illusions 3A lends credence to that opinion. But I also
have found that, in my limited experience, most gear in my system
sounds *very* similar and probably in most situations identical. There
have been periodic exceptions such as with the Audible Illusions. But
even then that line stage sounded very similar (but I don't believe
identical) to the other 4 line stages I auditioned in my system during
that period. The only pronounced difference was in the *extreme*
bottom where, for whatever reasons, whether it was due to a defect,
design limitation, an error on my part, or whatever, it seemed to roll
off. I still find it to be a damn good sounding line stage in my
opinion. It is still a superb line stage that I strongly recommend, if
you don't have speakers that reach to the lower octave and/or you
don't listen to organ music that may reach that low.
If I were looking for a two-channel line stage today I believe, based
on the input provided during this thread (although some of it was
expressed in a manner that was unnecessarily harsh), I would give the
3A another shot and bring some aspects of what I have learned here to
the audition. Because I do agree that things don't add up. That's
obvious. To that degree I regret not applying some measurements, for
example, or insisting that Audible Illusions do some since they are so
close geographically. I think that it could be fun and revealing.
Robert C. Lang
Robert C. Lang
> On 24 Oct 2004 15:16:37 GMT, lan...@pacbell.net (Robert C. Lang)
> wrote:
>
Literally
> >> >hundreds of times I have listened to the Telarc Michael Murray
> >> >performance of the Poulenc Organ Concerto. Heading into the final 3
> >> >minutes or so the recording (and at a live performance) I habitually
> >> >brace myself for a faint but *very* deep organ passage which is
> >> >sustained continuously for well over 90 seconds. Because it is
> >> >sustained it is easier to gauge than a transient. Telarc says that
> >> >this sustained note was at 23 HZ. It feels like a small earthquake (I
> >> >live in the San Francisco Bay Area).
> >> >
> >> >But with the Audible Illusions that sustained note simply did not
> >> >occur. It simply didn't happen. The faint groan of the organ didn't
> >> >happen, the *seemingly* change in the barometric pressure (for lack of
> >> >a better description) didn't happen, the very unique and easily
> >> >identifiable flutter of the floor didn't happen. Turning up the volume
> >> >to higher than normal did not make it happen. The bottom octave was
> >> >clearly rolled off.
> >>
> >> That may of course be literally true. Have you measured the frequency
> >> response of this generally well-regarded preamp?
>
>
> >engineers in the company) found my observations to be dispassionate
> >and plausible not to require measurements or dbts to confirm the
> >obvious. Audible Illusions (only 20 minutes away) had the opportunity
> >to make measurements; they chose not to. They came to the same
> >conclusions I did. That is, that there *was* an audible bass roll off
> >of the 3A in *my* system (not necessarily applicable to your system).
>
> They sound like classic 'high end' clowns with no technical expertise
> (or indeed *interest*) whatever. Did they not *care* that a purchaser
> was supposedly experiencing severe difficulties with their equipment?
>
> >Second, with respect to your remarkable propensity to curtly dismiss
> >others opinions and require corroborative proof for such, by English
> >definition *opinion* "is a belief or conclusion held with confidence,
> >but not substantiated by positive knowledge or proof". Opinions are by
> >*definition* unsubstantiated! This definition should be familiar to
> >you because I have offered to you on several occasions in the past.
>
> So, you admit that this 'lack of bass' is simply an opinion, and need
> not have any substance in the real physical world?
You may refer to it as "simply an opinion" if you like. While
certainly not infallible, I believe my opinion to be well-founded
based on pertinent observations and facts that do include "real
physical world" phenomena. As I said before "with the Audible
Illusions faint groan of the organ didn't happen, the *seemingly*
change in the barometric pressure (for lack of a better description)
didn't happen, the very unique and easily identifiable flutter of the
floor (physical world and a fact) didn't happen. The lamp vibration
(physical world and a fact) did not occur. Turning up the volume to
higher than normal did not make it happen. Yesterday you said, "That
may of course be literally true". Now today you say, without even so
much of a modicum of explanation for your reversal, "Your imagination
seems to be the most likely culprit".
In addition, my opinion of roll off of bass below 30 hz in *my* system
was backed with the unanimity of two engineers and Mr. Ferris at
Audible Illusions. Yesterday you referred to the Audible Illusions 3A
as "generally well regarded preamp" Today you say of key Audible
Illusion employees "They sound like classic 'high end' clowns with no
technical expertise
Ø (or indeed *interest*) whatever.
You clearly have nothing relevant or pertinent to add to this issue.
In addition, you have sunk to retaliating with remarks that are
deliberately inappropriate and offensively discourteous. What a
waste. You have clearly lost your way and should move on.
Robert C. Lang
Ø quelle surprise.........................
Robert C. Lang
said, in part, about the Audible Illusions 3A that:
"It is still a superb line stage that I strongly recommend, if you
don't have speakers that reach to the lower octave and/or you don't
listen to organ music that may reach that low".
My caveat should be deleted and rephrased to say that if an audiophile
is so inclined he or she should audition the 3A in their system
irrespective of how low their speakers go or what music they listen
to, because their experiences, particularly in the lowest audible
octave, could be different than mine.
Robert C. Lang
Robert C. Lang
> >> has a much lower input resistance, and that caused the output
> >> capacitance of the source to have a high-pass cut-off that is too high
> >> in frequency. Or that it has a coupling capacitor that is too small. Is
> >> there transformer coupling inside the unit? Do you have a schematic of
> >> the 3A?
> >
> >
> > On the manufacturer's website, the specs for the M3A say that the
> > error
> >> is +/- 1dB from 2 Hz to 100KHz for the high-level input. So that clearly
> >> does not agree with what you observed. Were you using the phono section?
> >
> > No. My observation was based primarily on the Telarc Poulenc Organ
> > Concerto CD.
>
> the spec sheet.
I believe there has been an assumption among many of us, myself
included, that the manufacturer's published specifications are
accurate and unquestioned. Is this something we can count on? Are
manufacturers specifications routinely independently verified?
I do believe that it is not uncommon that when a magazine measure's
gear that they are testing that one or more of the manufacturer's
specs are not met. And these are units that are *hand picked* by the
manufacturer. It seems that it is not uncommon for an amp, for
example, not to meet it's power ratings into 4 ohms and below,
headroom measurements can fall short, input sensitivity and impedance
levels don't measure up to what the claims are, etc. These don't
necessarily effect negative effect the performance of the gear, I
guess. Like wise, if the manufacturer says the frequency response of
said gear is flat 5HZ to 50khz but it really falls of at 25hz 99.8%
(guestimate) of users would not detect the shortfall.
I attempted (during the course of this thread) tried to find some
independent measurements done of the 3A. So far I have not been
successful.
> >> What you described can also be easily measured, if it was the high-level
> >> input that you were using. In fact, you can probably measure it yourself
> >> using a good voltmeter, if you have access to that unit. Play a test CD
> >> disc with constant-level low frequency tones, and see how the output
> >> level varies as you play different tones. It should be flat down to at
> >> least 20 Hz. Make sure that you connect the outputs of the preamp to the
> >> power amp while you make that measurement. > >
> > At my invitation Audible Illusion had every opportunity to make
> > measurements, while the pre amp was in my system as they are only 20
> > minutes away. They did not think it was necessary based on my
> > observations. By the way, the representatives of Audible Illusions
> > never doubted the validity of my observations (I have only used the
> > word "observation", never "evidence". Because as clearly stated in my
> > original comments (the ones made in February 2000 at
> > http://www.audioreview.com/Preamplifiers/Audible
> > Illusions/PRD_118448_1591crx.aspx#reviews) I had a strong bias in
> > favor of Audible Illusion because it is a local company and I had been
> > in direct contact with the company to arrange a purchase. Audible
> > Illusions took my observations and comments quite seriously and were
> > never cynical. They found my observations to be quite compelling (and
> > said so) because they involved more that just hearing (they also
> > involved sight [lamps not vibrating] and feel [vibration of floor].
> > Audible Illusions offered an explanation that I retrieved from the
> > archives of this group I made several years back.
>
> How could they have taken your comments seriously if they did not try to
> get to the cause of the problem? Or give you a replacement first?
Audible Illusions did check out the specific unit, a dealer loaner,
that I used and declared it a fully working unit. Also, I had several
lengthy conversations with several people at the company. Beyond that
I can't respond to your question.
>
> >
> > To put the Audible Illusion representative's comments in perspective
> > it should be noted that my system is bi-amped.
> >
> > "The day after I wrote my comments Art Ferris, of Audible
> > Illusions, in a email to me expressed his belief that because
> > I was "driving several amplifiers, electronic crossover
> > etc." he believed that the "paralleled load impedance" of my
> > amplifiers was well below the minimum load impedance of 20kohm.
>
> I would think that your electronic crossover is in *series* with the
> power amp, so that the preamp only sees the crossover as a load. Does
> your crossover has an extremely low input impedance, like less than 10K?
I just looked up the spec in the last published Audio Equipment Guide
(October 1999). The input impedance is listed at 50K ohms. For what
it's worth I see several listed with input impedances at 10k or less
(as low as 4).
>
> >
> > Mr. Ferris also expressed concern whether I was "running low
> > capacitance interconnect recommended for use with the
> > Audible Illusion 3A. He expressed that high capacitance
> > interconnects could account for bass roll-off.
>
> Mr. Ferris is clearly technically incompetent. You can ignore everything
> he said, based on that comment.
>
>
> >
> > Mr. Ferriss also stated that "in most normal systems", where
> > the pre amp is driving an amplifier with an input impedance
> > above 20kohm, I would not experience a problem."
>
> Assuming that the +/- 1dB spec at 2Hz is achieved at 50K loading as
> stated in the specs, it would take a load of 5K to move the -1dB point
> to 20 Hz, if the output coupling capacitor was causing the roll-off. (If
> some interstage cap or transformer was casuing the roll-off, then output
> loading should not make any difference.) And even that still does not
> account for your observations, which were more like -6dB or worse at 23 Hz.
>
> Seems like you had a defective M3A.
That was my thinking initially. As stated above Audible Illusions did
check out the specific unit and said it was fine. Also, to the ear,
the unit sounded very good, except for the very botoom octave. Of
course, it could have measured terribly, but Audible Illusions said it
was OK.
> > Robert C. Lang
Stewart Pinkerton
wrote:
There is no 'reversal' in stating that one thing may be true, but
another is more likely.
>In addition, my opinion of roll off of bass below 30 hz in *my* system
>was backed with the unanimity of two engineers and Mr. Ferris at
>Audible Illusions. Yesterday you referred to the Audible Illusions 3A
>as "generally well regarded preamp" Today you say of key Audible
>Illusion employees "They sound like classic 'high end' clowns with no
>technical expertise
>Ø (or indeed *interest*) whatever.
The one has, regrettably, nothing to do with the other! :-(
>You clearly have nothing relevant or pertinent to add to this issue.
>In addition, you have sunk to retaliating with remarks that are
>deliberately inappropriate and offensively discourteous. What a
>waste. You have clearly lost your way and should move on.
You seem detemined that your opinion is unchallengeable, and 'you know
what you heard'. This is a sadly all too common tale in this forum,
and tends to attract skepticism. You have an example of a
pre-amplifier which is claimed to be flat to 2Hz, and has been
measured flat to less than 10Hz by Stereophile, and yet you claim that
it heavily rolls off a 23Hz note, making it inaudible. You then report
a conversation with AI staff, where they say things that are utterly
impossible in electrical engineering terms, and yet you claim that I
am being 'inappropriate and offensively discourteous' by noting their
lack of expertise? Why will you not acknowledge the *only* two
possibilities here:
1) The preamp is seriously malfunctioning
2) No such difference exists in the physical world
A simple measurement would show which is the case. I would recommend
having it done in situ, rather than letting AI get their hands on it.
BTW, I note that, in terms of 'offensive discourtesy', you accuse me
of double standards, and of having refused to clarify my endorsement
of a particular component. Yet, when I ask you for some evidence of
what 'clarification' was requested, you are utterly silent. Double
standards, indeed...................
Chung
> Chung <chun...@covad.net> wrote in message news:<cle8p...@news2.newsguy.com>...
>> Robert C. Lang wrote:
>> > Chung <chun...@covad.net> wrote in message >
>> >
>> > I would guess that perhaps that unit
>> >> has a much lower input resistance, and that caused the output
>> >> capacitance of the source to have a high-pass cut-off that is too high
>> >> in frequency. Or that it has a coupling capacitor that is too small. Is
>> >> there transformer coupling inside the unit? Do you have a schematic of
>> >> the 3A?
>> >
>> >
>> > On the manufacturer's website, the specs for the M3A say that the
>> > error
>> >> is +/- 1dB from 2 Hz to 100KHz for the high-level input. So that clearly
>> >> does not agree with what you observed. Were you using the phono section?
>> >
>> > No. My observation was based primarily on the Telarc Poulenc Organ
>> > Concerto CD.
>>
>> In that case, there is a huge discrepancy between your observations and
>> the spec sheet.
>
> I believe there has been an assumption among many of us, myself
> included, that the manufacturer's published specifications are
> accurate and unquestioned. Is this something we can count on? Are
> manufacturers specifications routinely independently verified?
Well, we have certainly seen published specs that do not agree with
measurements. However, it is trivially easy to make a preamp that does
not roll off 23 Hz. I may believe that the flatness spec does not extend
to 2Hz, but I would be shocked to find that it only extends to 30 Hz or
so. That's more than a decade off! Or about 4 octaves!
>
> I do believe that it is not uncommon that when a magazine measure's
> gear that they are testing that one or more of the manufacturer's
> specs are not met. And these are units that are *hand picked* by the
> manufacturer. It seems that it is not uncommon for an amp, for
> example, not to meet it's power ratings into 4 ohms and below,
> headroom measurements can fall short, input sensitivity and impedance
> levels don't measure up to what the claims are, etc. These don't
> necessarily effect negative effect the performance of the gear, I
> guess. Like wise, if the manufacturer says the frequency response of
> said gear is flat 5HZ to 50khz but it really falls of at 25hz 99.8%
> (guestimate) of users would not detect the shortfall.
In that case, the product is simply defective, if it's supposed to be
flat to 5Hz and measures flat only to 25Hz.
It makes you wonder what kind of QA the manufacturer has. You have to
understand that the flatness spec is dictated by passive components like
capacitors where it is common to obtain +/- 10% tolerances. Which means
the -3dB frequency should only be off by about 10%, not a factor of 10.
So it measures flat (-1dB) to 2Hz. Which makes one wonder why they
accepted your observations at full face value.
> Also, I had several
> lengthy conversations with several people at the company. Beyond that
> I can't respond to your question.
>>
>> >
>> > To put the Audible Illusion representative's comments in perspective
>> > it should be noted that my system is bi-amped.
>> >
>> > "The day after I wrote my comments Art Ferris, of Audible
>> > Illusions, in a email to me expressed his belief that because
>> > I was "driving several amplifiers, electronic crossover
>> > etc." he believed that the "paralleled load impedance" of my
>> > amplifiers was well below the minimum load impedance of 20kohm.
>>
>> I would think that your electronic crossover is in *series* with the
>> power amp, so that the preamp only sees the crossover as a load. Does
>> your crossover has an extremely low input impedance, like less than 10K?
>
> I just looked up the spec in the last published Audio Equipment Guide
> (October 1999). The input impedance is listed at 50K ohms. For what
> it's worth I see several listed with input impedances at 10k or less
> (as low as 4).
>>
If the spec'd impedance is 50K and it measures 10K or less, it's broken.
You think your crossover is broken? Except if it's broken, wouldn't
other preamps have the same problem driving it?
Stewart Pinkerton
wrote:
>Chung <chun...@covad.net> wrote in message news:<cle8p...@news2.newsguy.com>...
>> Robert C. Lang wrote:
>> > Chung <chun...@covad.net> wrote in message >
>I attempted (during the course of this thread) tried to find some
>independent measurements done of the 3A. So far I have not been
>successful.
Try something sophisticated - type 'Audible Illusions 3A' into Google.
The first two hits should be the Stereophile review. This technical
review shows a frequency response ruler-flat to 10Hz, the lower limit
of their measurements.
>> > To put the Audible Illusion representative's comments in perspective
>> > it should be noted that my system is bi-amped.
>> >
>> > "The day after I wrote my comments Art Ferris, of Audible
>> > Illusions, in a email to me expressed his belief that because
>> > I was "driving several amplifiers, electronic crossover
>> > etc." he believed that the "paralleled load impedance" of my
>> > amplifiers was well below the minimum load impedance of 20kohm.
>>
>> I would think that your electronic crossover is in *series* with the
>> power amp, so that the preamp only sees the crossover as a load. Does
>> your crossover has an extremely low input impedance, like less than 10K?
>
>I just looked up the spec in the last published Audio Equipment Guide
>(October 1999). The input impedance is listed at 50K ohms. For what
>it's worth I see several listed with input impedances at 10k or less
>(as low as 4).
I reiterate my comment that Ferris is technically incompetent. Note
that I'm not the only one in this thread holding that opinion.
>> > Mr. Ferris also expressed concern whether I was "running low
>> > capacitance interconnect recommended for use with the
>> > Audible Illusion 3A. He expressed that high capacitance
>> > interconnects could account for bass roll-off.
>>
>> Mr. Ferris is clearly technically incompetent. You can ignore everything
>> he said, based on that comment.
>> >
>> > Mr. Ferriss also stated that "in most normal systems", where
>> > the pre amp is driving an amplifier with an input impedance
>> > above 20kohm, I would not experience a problem."
>>
>> Assuming that the +/- 1dB spec at 2Hz is achieved at 50K loading as
>> stated in the specs, it would take a load of 5K to move the -1dB point
>> to 20 Hz, if the output coupling capacitor was causing the roll-off. (If
>> some interstage cap or transformer was casuing the roll-off, then output
>> loading should not make any difference.) And even that still does not
>> account for your observations, which were more like -6dB or worse at 23 Hz.
>>
>> Seems like you had a defective M3A.
>
>That was my thinking initially. As stated above Audible Illusions did
>check out the specific unit and said it was fine. Also, to the ear,
>the unit sounded very good, except for the very botoom octave. Of
>course, it could have measured terribly, but Audible Illusions said it
>was OK.
If it was even close to its specification (like three times worse), it
would be totally flat to that 23 Hz note you're complaining about.
What you're claiming simply does not stack up in physical reality.
Chung
>
> In addition, my opinion of roll off of bass below 30 hz in *my* system
> was backed with the unanimity of two engineers and Mr. Ferris at
> Audible Illusions.
Did those people listen to the M3A in *your* system and agreed that the
bass was indeed rolled off? Or did they simply agree with you without
listening to it, but having made measurements on it?
Stewart Pinkerton
Oh dear, not the Fiedler fiddle again! It's hard to know whether this
was a deliberate distortion by Fiedler, not picked up by Everest, or
simply an engineering figure that is being misinterpreted by the
reader. Given the convenient claim that 16 bits are inadequate, I tend
to suspect the former. However, the following are why this is not a
realistic figure to use for determining real-word requirements:
1) The 118dB figure refers to close miking. Note that in many
orchestras, the poor players sitting in front of the brass section
often use acoustic baffles to prevent hearing damage - and to allow
them to hear their own instruments! This is definitely *not* a
realistic figure to use, when it is not representative of what any
audience member would hear, even from the very front stalls.
2) I believe you'll find that the 113dB figure also refers to close
miking, as the difference quoted is simply that between heavily
percussive and 'normal' symphonic events. I'm not aware of any figures
taken from the usual 'simple miking' position about twelve feet above
and behind the conductor, which exceed 110dB peak SPL for any
orchestral piece, including Mahler and Wagner.
3) Please note the base measure used for the above - the just-audible
threshold of white noise in an otherwise quiet environment. This is
0dB SPL. IOW, what Fieldler is quoting is peak SPLs at one end of the
range, and assuming a 'threshold of hearing' bottom limit. This is
farcically unrealistic even for a studio recording, where the
self-noise of the *microphones* will be above 20dB SPL, and the true
wideband noisefloor of the venue will be not less than 30dB. Move to a
real reverberant concert hall, where the music will always sound
better than an artificially reverb'd studio recording, and the noise
floor will jump to a typical 40dB.
3a) Note that when we're back in the real world, that artificial
reverb which is *essential* to avoid a studio recording sounding
horribly sterile, will in and of itself raise the noise floor by 4-8
dB.
4) Despite the desperate attempts by Fiedler to come up with some
reason why we need hi-res replay formats (note that no one denies the
usefulness of 24-bits for *recording*, to allow room for accidental
mic overloads and EQ), there is no record of *any* real master tape of
an acoustic musical event (i.e. no synthesisers) which exceeds 80-85dB
dynamic range, and indeed most 'live' classical recordings have more
like 60-70dB range. Why therefore does Fiedler claim that we *need*
more than 93dB? More importantly, why is he using the utterly
unrealistic 0dB SPL as his base reference?
Stewart Pinkerton
wrote:
If the unit is not broken, they could not fail to be different, since
this unit *measures* ruler-flat to less than 10Hz.
Bob Marcus
>
> I believe there has been an assumption among many of us, myself
> included, that the manufacturer's published specifications are
> accurate and unquestioned. Is this something we can count on? Are
> manufacturers specifications routinely independently verified?
Not so far as I know. There are consumer fraud laws and
truth-in-advertising requirements, but these are largely unenforced
unless someone brings a specific complaint. Furthermore, there are
always multiple ways to take a measurement, so it's quite possible
that there is SOME circumstance under which a product meets spec. But
if that circumstance is utterly unrealistic, then the spec is, while
technically accurate, highly misleading to consumers. And the people
who publish those specs know exactly what they are doing.
A spec sheet is a marketing document. Consumers should read it with
the same skepticism they would bring to any other advertisement.
bob