"Tube watts" vs. "solid state watts"

[RichL]

Just thinking about some of the posts in the "DIY setup" thread and decided
to clarify and stimulate discussions (hopefully attack-free)!

How are amps rated? When a manufacturer says a particular amp is a "30
Watt" amp, what is meant?

First, one stipulation. Amp rated power doesn't mean the power radiated
acoustically from the speakers. It means power delivered to the speakers.

But let's get more specific. Most honest manufacturers rate an amplifier
according to the largest output power it can produce without exceeding a
certain level of total harmonic distortion (THD), and the good ones will
specify that THD level (usually expressed as a percentage). THD is defined
here:

http://en.wikipedia.org/wiki/Total_harmonic_distortion

The power rating of an amp depends on the level of THD specified. An amp
rated at 30 W, 1% THD is louder than one rated at 30 W, 10% THD. That's
because the amount of distortion (obviously) depends on how hard the amp is
driven, and for a given amp you reach the 1% THD point at lower output power
than you do the 10% THD point.

By the way, 1% THD is a typical spec.

So what's all this got to do with "Tube watts" vs. "Solid state watts"?

It's pretty simple, really. What it comes down to is this: musical
instrument amplifiers can produce power in excess of the power at which the
THD specification is achieved. For the audio purist, you don't want to go
past the 1% THD point (some perfectionists would insist on much lower THD
for accurate music reproduction). But guitarists can tolerate, and in fact
many would prefer, distortion well beyone the 1% level.

How much beyond? It depends on whether it's a SS amp or a tube amp!!

For solid state devices, the onset of clipping is abrupt, and most of us
would agree that a SS amp driven beyond clipping sound harsh and unpleasant;
you don't want to take a SS amp there!

So what's the THD for a SS amp driven to clipping? I haven't done a survey,
but here's an example of a TI class-D audio power amp:

http://www.ti.com/lit/ds/symlink/tpa3007d1.pdf

The interesting thing here, not peculiar to this particular amp, is the
following statement, which you will find on p. 12 of the PDF:

"Clipping is typically quantified by a THD measurement of 10%."

Check also the statement following: The power output at 10% THD is 1.25
times the power output at 1% THD. So a SS guitar amp rated at 30 W at 1%
THD is putting out 37.5 W if it is on the edge of clipping (i.e., at 10%
THD).

Now let's look at tube amps. Unlike SS amps, the onset of clipping is not
abrupt in tube amps; the clipping is said to be "soft" rather than the
"hard" character of SS amps. Read more here:

http://en.wikipedia.org/wiki/Tube_sound#Soft_clipping

The point is, in tube amps you can go way past the ~10% THD limit
characteristic of SS amps and STILL SOUND GOOD! Which in turn means that
for a tube amp rated at 30 W @ 1% THD, you can get well past the output
power limit of 37.5 W for the SS example described above and still have the
amp producing sound that's pleasing to the ear!

So, in essence, for a tube amp and a SS amp that are rated the same in terms
of power at 1% THD, the tube amp is capable of producing more "USABLE WATTS"
than the SS amp!

How much more? Well, it depends on who's doing the playing, I suppose. I'd
imagine a jazz guy doesn't want much distortion (despite it being a good
thing for us rockers), so the distinction between a tube amp and a SS amp in
terms of USABLE WATTS is probably close to meaningless to him.

But if you find tube distortion to be a positive feature of a tube amp, yes,
you'll get much more USABLE watts out of a tube amp with a given power
rating than out of a SS amp with the same rating.

That is all.

Discuss.

[Little Charlie]

On Tue, 8 Nov 2011 19:25:04 -0500, "RichL" <rple...@yahoo.com>
wrote:

Good read Rich..rtewally. Jives with my Sun Devil-BSEE all the way
Jose'

What's your take on ss amps that employ 'modeling' of tube amp
reproduction? Or the numerous boxes that simulate specific amp brands,
models - and- even vintages..?? 'ain't nothing like tthe real thing?"
If one has roadies or a partner to carry all my tube stuff..no
prob..shit the ss amps I'v had (medium sized stuff) were 40-55
lbs..FTS. I can usally get a patron or two to haul my crap after I'm
pooped-out..some are anxious to help..good deal Lucille!!

anyway well written stuff...IMHO TY

[RichL]

"Little Charlie" <le...@live.com> wrote in message
news:hjkjb7lo9i54m0hsp...@4ax.com...

Thanks!
I don't have much direct experience with modeling amps. I did recently get
a Line 6 Pod 2.0, I figured it was much cheaper than getting a really
high-gain amp (which I don't have), but generally out of the 32+ amp
simulations, I'd rate about four of them to be decent. Still worth the cost
for those four sounds though. But generally, I'm old school and I prefer a
real tube amp, although I've got ONE solid-state amp, a Roland Jazz Chorus
77, that I'd rate pretty highly.

[Little Charlie]

On Tue, 8 Nov 2011 20:24:22 -0500, "RichL" <rple...@yahoo.com>
wrote:

TY what are those few you rate above the others in this scenario?

[Craig 'Lumpy' Lemke]

RichL wrote:
> How are amps rated? When a manufacturer says a particular amp is a
> "30 Watt" amp, what is meant?

I think they're rated any way the advertising people
want to rate them. RMS, peak to peak,
Peak Music Power (whatever that is),
Super Hetrodyne Isotropic Transient power.


Lump

[RichL]

"Little Charlie" <le...@live.com> wrote in message

news:c4mjb7d31fkgd19vq...@4ax.com...

Not sure I understand the question. You mean on the POD? I'd have to go
through and listen again, I just got it recently and I don't remember which
setting were the "good" ones.

As far as amps go I read what I wrote and realized I might have been
misunderstood. I have ONE SS amp, the Roland, but I also have a Vox AC30, a
Fender Twin Reverb, a Marshall JCM 800 2204, a Fender Blues Jr., and an
Epiphone Valve Jr. The AC30 is my workhorse, followed closely by the
Marshall.

[Little Charlie]

Lump..thats a bunch of SHIT..and you know it...he he
cj

[Pt]

On Nov 8, 7:24 pm, "RichL" <rpleav...@yahoo.com> wrote:
> "Little Charlie" <le...@live.com> wrote in message
>
> news:hjkjb7lo9i54m0hsp...@4ax.com...
>
>
>
>
>

> > On Tue, 8 Nov 2011 19:25:04 -0500, "RichL" <rpleav...@yahoo.com>

> 77, that I'd rate pretty highly.-

I had a Jazz Chorus 120.
Great amp.

Pt

[Little Charlie]

On Tue, 8 Nov 2011 22:33:49 -0500, "RichL" <rple...@yahoo.com>

Thanks that clears it up...my mentor Robert Luke Lucas prized and old
Fender amp he used all torn to shit but with him it sounded great.
It's on the cover of his 'Layaway' cd..see it on Amazon.

Got to know Luke in Arizona as his folks were wealthy residents there
and he would come through to see them from time-to-time. His first CD
for Audioquest had an endorsement on the back from none other than
Willie Dixon...words like " this CD is how the Blues sounded back when
I was coming up' Luke must have shown me that quote a doizen
times..what a endorsement holy crapola...

Wille's book "I Am the Blues' is a great read. He was a huge force not
just musically in Chicago BUT also helping new arrivals (musiccians
from MS) to get them work and keep them advised how not to get screwed
in the music business....in later years Led Zepplin would pay a
settlement to him for plagarism.

[Charmed Snark]

RichL expounded in news:5cmdnTIiiMHsVSTT...@supernews.com:

> How are amps rated? When a manufacturer says a particular amp is a
> "30 Watt" amp, what is meant?

..

> But let's get more specific. Most honest manufacturers rate an
> amplifier according to the largest output power it can produce
> without exceeding a certain level of total harmonic distortion (THD),
> and the good ones will specify that THD level (usually expressed as a
> percentage). THD is defined here:
>
> http://en.wikipedia.org/wiki/Total_harmonic_distortion
>
> The power rating of an amp depends on the level of THD specified. An
> amp rated at 30 W, 1% THD is louder than one rated at 30 W, 10% THD.
> That's because the amount of distortion (obviously) depends on how
> hard the amp is driven, and for a given amp you reach the 1% THD
> point at lower output power than you do the 10% THD point.
>
> By the way, 1% THD is a typical spec.

First of all, in SS terms, 1% THD is horrible! More on that later.

This was precisely what I presented not too long ago. But some folks
"don't like rules". They want to compare results without any defined
method.

> So what's all this got to do with "Tube watts" vs. "Solid state
> watts"?
>
> It's pretty simple, really. What it comes down to is this: musical
> instrument amplifiers can produce power in excess of the power at
> which the THD specification is achieved.

No argument as stated but of course implied in this is that the excess
power is also producing excess distortion.

> For the audio purist, you
> don't want to go past the 1% THD point (some perfectionists would
> insist on much lower THD for accurate music reproduction). But
> guitarists can tolerate, and in fact many would prefer, distortion
> well beyone the 1% level.
>
> How much beyond? It depends on whether it's a SS amp or a tube amp!!

As I was a sayin', this goes _beyond_ the "ratings".

See this is the thing- if you don't care about THD, you could build a ss
amp (or even a tube one) that spews out gobs of crap. If you don't care
about distortion almost anything can deliver more power. Of course, were
talking about pleasing distortion here -- that "artistic element".

> For solid state devices, the onset of clipping is abrupt, and most of
> us would agree that a SS amp driven beyond clipping sound harsh and
> unpleasant; you don't want to take a SS amp there!

One has to be careful about making general statements here. This is
definitely in the realm of general experience (I would think), but does
not necessarily make it generally so. There are several distortion
mechanisms, some soft, some not so.

> So what's the THD for a SS amp driven to clipping?

You must take into account is what kind of clipping is going on. First of
all, almost all distortion pedals use semiconductor diodes to create the
distortion (FETs in more exotic ones). Yet people are not objecting to
that tone..

The bad distortion in ss amps can come from a number of sources:

- is it [hard] clipping in the preamp (bad design)?
- hitting the limit of the class B power capability?
- is the SOAR circuit being activated to keep the trannies
in the Safe Operating Area Range?
- is the speaker protection circuit being activated?

Any or all these are factors in the output when you exceed maximum
ratings of a ss amp. There's much more variation in ss power amp designs
than there is in tube amps. It is therefore, much more difficult to
generallize.

Tube amps have no protection systems at all, or I'm not aware of any in
guitar amplifiers. At most a fuse or thermal cutoff. Tube hifi/stereos
may have a small number of special design cases. A tube amp will let you
run it until you melt the tubes, the OPT or the power transformer or it
simply catches on fire.

A SS amp OTOH, must protected the output transistors. They don't just
glow red and more-or-less return to normal when you shut it off. The
semiconductor junction just phzzzsssts instead! Nor are power transistors
as convenient to change. Adjusting a class B ss amp is trickier as well.
So keeping them safe is very worthwhile.

Specialized circuits are added to the ss power amp so that if
voltage+current crosses an eliptical Safe Operating Area Range that they
start removing the drive into the base of the power tranny. So obviously
when this limiting is occurs, the audio "quality" is sacrificed in the
process (but saves the amp).

Then there is the speaker protection circuit. Since any SS worth it's
salt today has _NO_ heaving tone sucking output transformer. The ss power
finals are coupled directly to the speaker (except for some capacitively
coupled amps which tend to be lower power). Since speakers can cost more
than the power transistors, there is a safety circuit there also. This is
in case only one driving side blows and DC current flows continously
through the speaker(s). The design of these circuits vary _enormously_
ranging from crowbar circuits that blow fuses to a signal foldback scheme
similar to the SOAR protection.

What most folks think about is the effect of the power trannies
themselves and this too can be a factor. However, in a well designed SS
amp, this doesn't happen since NFB generally corrects this. It can happen
just before SOAR kicks in where the trannies hit limits that NFB cannot
correct any further.

But here is the single most important thing about ss amplifier ratings,
when it comes to power: they tend to be _absolute_ _maximum_ ratings. A
ss amp will maintain excellent low THD distortion up to its absolute
maximum limit, due the use of fairly high NFB. Tube amps OTOH have
distortion figures climbing quickly as the power level rises near the
limit.

Once you cross that power rating line, NFB might not be able to help
(depends upon design), or a protection mechanism is activated. In any
case, hard limits are involved.

But can you blame this design? The maximum rating is a maximum rating.

With a tube amp, the THD starts to rise quickly but it isn't as sudden
as the SS as it crosses the limit. The tube amp has no protection
mechanisms and nothing to act as a hard limit. But everyone does know the
THD has suddenly risen in the tube amp because it is quite audible.

But this does not mean one amp's watts are different than the other?

Nope.

You can just as easily pit a bigger ss amp against a tube amp and win
that fight. It's just that the ss amp is rated at it's hard limit.

So the comparison problem is that if you ignore the tube amp's THD, it's
power rating is not actually the _maximum_ power rating for that tube amp
(it is actually higher). Of course this means adjusting the audio
quality (THD), which is what musicians do.

> The point is, in tube amps you can go way past the ~10% THD limit
> characteristic of SS amps and STILL SOUND GOOD! Which in turn means
> that for a tube amp rated at 30 W @ 1% THD, you can get well past the
> output power limit of 37.5 W for the SS example described above and
> still have the amp producing sound that's pleasing to the ear!
>
> So, in essence, for a tube amp and a SS amp that are rated the same
> in terms of power at 1% THD, the tube amp is capable of producing
> more "USABLE WATTS" than the SS amp!

Again, this is because, if you discard the audio quality requirement, you
then accept that the tube amp's rating wasn't an absolute maximum rating
after all. IOW, if you now agree that 10% THD is ok, then you've
implicitly increased the power rating of that tube amp in the process.

But a normal SS amp (I can't speak to class D) is good right up to its
maximum rating. Right up to the bitter end (unlike a tube amp).

NOW, if you turn that around and made the power rating to 0.002% THD,
which ss amps quite easily achieve today, SS would trounce the avg tube
(guitar) amp! SS can trounce them in quality. Tubes are noisy and the
traditional g amp tube designs are not going to provide that level of
performance that SS can.

> But if you find tube distortion to be a positive feature of a tube
> amp, yes, you'll get much more USABLE watts out of a tube amp with a
> given power rating than out of a SS amp with the same rating.
>
> That is all.
>
> Discuss.

A lot of things are done in the name of tone. The two technologies are
very different to be sure. I'll also suggest that if you want an
acoustic amplifier, you want that 0.002% THD figure (not the lousy 1%).

Framing the statement "tube watts > ss watts" does not convey all of the
finer points involved.

If you're goint to agree 10% THD is ok, then your 100W tube amp would be
rated at 150W then (@ 10%THD). A competing 0.002% SS amp is perfect up to
that 100W limit and then goes ballistic in crap over 100W.

But clearly this is no mystery- we're now comparing a 150W tube amp to a
100W ss amp! It's no surprise then that the 150W amp wins. But if you
put a 151W ss amp up against it, ss would then win.

Watts is watts.

Snark.

[Tony Done]

"Craig 'Lumpy' Lemke" wrote in message
news:j9cqk2$kos$1...@speranza.aioe.org...

Yeah, I'm getting a bit cynical about output/loudness. My 2* EL84 H&K should
put out about 18w, the Blues Deluxe is supposedly 40w, yet the clean channel
on the H&K is *much* louder than the BD clean channel. My tech mate Terry
tried to get me interested in the Ibanez Tubescreamer amp on Saturday, 2*6V6
and supposedly 5/15w on a triode/pentode switch. Even in 15w mode the clean
channel was quieter than my Epi VJ with the power soak engaged,
theoretically less than 2.5w. I asked if there was something wrong with it,
but the sales assistants said it was similar to one they had sold earlier.
FWIW, the Tubescreamer front end also sounded ordinary to me.

Tony D

[RichL]

"Charmed Snark" <sn...@cogeco.ca> wrote in message
news:Xns9F97F2C5F152DS...@88.198.244.100...

> If you're goint to agree 10% THD is ok, then your 100W tube amp would be
> rated at 150W then (@ 10%THD).

Ah, but that's my point, sort of. My 100 W tube amp isn't rated at 10% THD,
at least the way people talk about them and manufacturers promote them.
Usually the data isn't even available to consumers.

I'm wondering how much THD (and how many watts I'm actually feeding the
speakers) I've got with my AC30 cranked up all the way. At that level, as
far as "musicality" is concerned, the sound being produced is still
pleasing, some would say extremely desirable!

> A competing 0.002% SS amp is perfect up to
> that 100W limit and then goes ballistic in crap over 100W.
>
> But clearly this is no mystery- we're now comparing a 150W tube amp to a
> 100W ss amp! It's no surprise then that the 150W amp wins. But if you
> put a 151W ss amp up against it, ss would then win.
>
> Watts is watts.

But I'd say that generally, a tube amp described by its manufacturers as a
30 W amp (without further clarification) is capable of producing more power
in a regime defined by its users (i.e, guitarists) as "desirable" than a SS
amp rated similarly by its manufacturers.

[Jim]

On 11/9/2011 10:29 PM, RichL wrote:
> "Charmed Snark" <sn...@cogeco.ca> wrote in message
> news:Xns9F97F2C5F152DS...@88.198.244.100...
>
>> If you're goint to agree 10% THD is ok, then your 100W tube amp would be
>> rated at 150W then (@ 10%THD).
>
> Ah, but that's my point, sort of. My 100 W tube amp isn't rated at 10%
> THD, at least the way people talk about them and manufacturers promote
> them. Usually the data isn't even available to consumers.
>
> I'm wondering how much THD (and how many watts I'm actually feeding the
> speakers) I've got with my AC30 cranked up all the way. At that level,
> as far as "musicality" is concerned, the sound being produced is still
> pleasing, some would say extremely desirable!

Your Vox probably pretty clean at 30W, and pretty dirty by 33W, with
another three or so watts of really compressed distortion. Note that
biased differently and with higher voltages, an EL84 can produce more
power. But not your cathode biased amp.

I don't really buy the "a 100W tube amp will put out 150W when
distorted" theory. None of the amps I have ever tested will do that.
Even fixed bias with higher plate voltages. At lower frequencies, most
tube amps distort more than at 400Hz or 1k.

You just can't assume that all amps display the same linearity. Some
factors include circuit design (including bias, class and negative
feedback) power supply design and limitations, and even tube choice.

>
>> A competing 0.002% SS amp is perfect up to
>> that 100W limit and then goes ballistic in crap over 100W.

I'd sure like to know what amp Snark is talking about! I'd like to see
independent testing to verify .002% throughout the bandwidth and power
scale (most amps put out additional distortion at low around 1W and
below, they actually clean up at a few watts through the rated output).

I'm not "an expert" on SS amps, or an "audiophool." However, my Mark
Levinson 33H (which is considered by many "audiophools" to be one of the
best amps EVER built) isn't even THAT clean (like it would matter,
because it would be AWFUL tough to hear the difference between .002% and
.01% with music playing through it).

>>
>> But clearly this is no mystery- we're now comparing a 150W tube amp to a
>> 100W ss amp! It's no surprise then that the 150W amp wins. But if you
>> put a 151W ss amp up against it, ss would then win.
>>
>> Watts is watts.
>
> But I'd say that generally, a tube amp described by its manufacturers as
> a 30 W amp (without further clarification) is capable of producing more
> power in a regime defined by its users (i.e, guitarists) as "desirable"
> than a SS amp rated similarly by its manufacturers.

Watts may be watts ON A TEST BENCH. But tone is tone to the EARS of a
musician. And that's why the vast majority of professional musicians
choose tube amps.

What Snark seems to forget is that the guitar amplifier is an extension
of the guitar. The amp IS a musical instrument, just like the guitar.

I could easily play my guitar through my Mark Levinson 33H. But WHY???
I'm not after a pure voltage source that will accurately reproduce the
output from my pickups. I'm after TONE. I am producing music, not
REproducing it.

That's why I choose TUBES FOR GUITAR, and solid state for stereo/home
theater.

[Jim]

On 11/8/2011 4:25 PM, RichL wrote:
> Just thinking about some of the posts in the "DIY setup" thread and
> decided to clarify and stimulate discussions (hopefully attack-free)!
>
> How are amps rated? When a manufacturer says a particular amp is a "30
> Watt" amp, what is meant?

While there are some standardized methods for hifi/stereo/home theater,
they often aren't followed with guitar/MI/PA amps. There was a recent
thread on alt.guitar.bass discussing a manufacturer who advertised an
amp at "X" watts, because they claim that the design allows it to SOUND
LIKE a typical amp rated at "X" watts!

But here's how my JBL 6290 is rated:

"Rated Power is minimum continuous sine wave output per channel with
both channels driving their rated load over a power bandwidth of 20 to
20k Hz. Maximum total harmonic distortion measured at any power level
from 250 mW to rated power is less than .1% for 8 ohm stereo and 16 ohm
bridge, .2% for 4 ohm stereo and 8 ohm bridge."

>
> First, one stipulation. Amp rated power doesn't mean the power radiated
> acoustically from the speakers. It means power delivered to the speakers.

That's for sure! It's hard to get actual specs on this, but the EVM12L
in a Thiele TL806 cab (like Mesa uses -- and efficient driver in an
efficient cab) only gives you 6% efficiency! And that's an efficient
setup for a single driver.

>
> But let's get more specific. Most honest manufacturers rate an amplifier
> according to the largest output power it can produce without exceeding a
> certain level of total harmonic distortion (THD), and the good ones will
> specify that THD level (usually expressed as a percentage). THD is
> defined here:
>
> http://en.wikipedia.org/wiki/Total_harmonic_distortion
>
> The power rating of an amp depends on the level of THD specified. An amp
> rated at 30 W, 1% THD is louder than one rated at 30 W, 10% THD.

I'm sure you mean CAN be louder, if you push that 1% rated amp even
harder. The 10% distortion amp will actually sound louder than the 30W
at 1%. That's because the human brain hears distortion as louder than
the same power level of clean power.

That's
> because the amount of distortion (obviously) depends on how hard the amp
> is driven, and for a given amp you reach the 1% THD point at lower
> output power than you do the 10% THD point.
>
> By the way, 1% THD is a typical spec.

Tube amps are often rated at 5% THD.

>
> So what's all this got to do with "Tube watts" vs. "Solid state watts"?
>
> It's pretty simple, really. What it comes down to is this: musical
> instrument amplifiers can produce power in excess of the power at which
> the THD specification is achieved. For the audio purist, you don't want
> to go past the 1% THD point (some perfectionists would insist on much
> lower THD for accurate music reproduction).

Other than for a subwoofer amp, yes. You really don't notice 1%
distortion in the lowest couple of octaves.

> But guitarists can tolerate,
> and in fact many would prefer, distortion well beyone the 1% level.

And that's the real issue! The amp is an extension of the instrument. A
tube guitar amp IS a musical instrument. It is producing music, not
merely reproducing it.

When you reproduce music, you want accuracy, and that's where solid
state excels.

When you produce music, the amp is a musical instrument, and these
comparisons of "a watt is a watt" because counterproductive and
meaningless. This is NOT a bench competition, it is real amps in the
real world, where musicians don't have a power meter on their amps and
where they don't follow "rules."

>
> How much beyond? It depends on whether it's a SS amp or a tube amp!!
>
> For solid state devices, the onset of clipping is abrupt, and most of us
> would agree that a SS amp driven beyond clipping sound harsh and
> unpleasant; you don't want to take a SS amp there!

All you have to do is look at distortion test results for high end solid
state. Once the rated output is reached, things get UGLY, and they get
ugly real FAST. It's like a brick wall of crap. Exactly what you DO NOT
WANT with a guitar, because you can be playing along and then really
bang your strings and easily double the voltage at the pickup.

>
> So what's the THD for a SS amp driven to clipping? I haven't done a
> survey, but here's an example of a TI class-D audio power amp:
>
> http://www.ti.com/lit/ds/symlink/tpa3007d1.pdf
>
> The interesting thing here, not peculiar to this particular amp, is the
> following statement, which you will find on p. 12 of the PDF:
>
> "Clipping is typically quantified by a THD measurement of 10%."

For most decent solid state amps, that's a bit meaningless because
they'll shoot from 2% to 10% in a matter of a couple of watts, or a few
percent of the rated output. You aren't buying much more actual audio
output from the 2% level to the 10% level.

>
> Check also the statement following: The power output at 10% THD is 1.25
> times the power output at 1% THD.

Not any amp that I'd own. A good solid state amp is going to be
designed to run as clean as possible, squeezing pretty much what they
can get out of the design. I'm pretty sure that all of my SS amps would
soar from 1% to 10% in less than 110% rated output (not 125%). But not
all amps behave the same.

> So a SS guitar amp rated at 30 W at 1%
> THD is putting out 37.5 W if it is on the edge of clipping (i.e., at 10%
> THD).
>
> Now let's look at tube amps. Unlike SS amps, the onset of clipping is
> not abrupt in tube amps; the clipping is said to be "soft" rather than
> the "hard" character of SS amps. Read more here:
>
> http://en.wikipedia.org/wiki/Tube_sound#Soft_clipping
>
> The point is, in tube amps you can go way past the ~10% THD limit
> characteristic of SS amps and STILL SOUND GOOD!

BINGO!

> Which in turn means that
> for a tube amp rated at 30 W @ 1% THD, you can get well past the output
> power limit of 37.5 W for the SS example described above and still have
> the amp producing sound that's pleasing to the ear!

Based on specs of amps that I own, I'd revise that 37.5W for SS down
some, but I agree with your discussion 100%.

And lets think about what happens when you're playing guitar in the real
world. When you stomp on your OD/distortion/boost pedal, or even hit
the strings harder. You can find the FUGLY SS wall real quick! ...but
with a tube amp, there will be compression (tubes are not as linear as
SS) and a softer, "warmer, more musical sounding" distortion with
different harmonic components.

>
> So, in essence, for a tube amp and a SS amp that are rated the same in
> terms of power at 1% THD, the tube amp is capable of producing more
> "USABLE WATTS" than the SS amp!

And will sound better when operated near the rated output. At least
without some good limiting and/or compression.

[Jim]

On 11/8/2011 10:51 PM, Tony Done wrote:
>
>
> "Craig 'Lumpy' Lemke" wrote in message
> news:j9cqk2$kos$1...@speranza.aioe.org...
>
> RichL wrote:
>> How are amps rated? When a manufacturer says a particular amp is a
>> "30 Watt" amp, what is meant?
>
> I think they're rated any way the advertising people
> want to rate them. RMS, peak to peak,
> Peak Music Power (whatever that is),
> Super Hetrodyne Isotropic Transient power.
>
>
> Lump
>
> Yeah, I'm getting a bit cynical about output/loudness. My 2* EL84 H&K
> should put out about 18w, the Blues Deluxe is supposedly 40w, yet the
> clean channel on the H&K is *much* louder than the BD clean channel.

Same speakers? Can you boost the BD either at the front end or loop to
get more clean volume?

My
> tech mate Terry tried to get me interested in the Ibanez Tubescreamer
> amp on Saturday, 2*6V6 and supposedly 5/15w on a triode/pentode switch.
> Even in 15w mode the clean channel was quieter than my Epi VJ with the
> power soak engaged, theoretically less than 2.5w.

With the VJ clean? That's a disappointment!

If you're talking the VJ when distorted, then you probably already know
this, but: The human brain perceives distorted sounds as louder than
non-distorted sounds at the same power (SPL) level.

I asked if there was
> something wrong with it, but the sales assistants said it was similar to
> one they had sold earlier. FWIW, the Tubescreamer front end also sounded
> ordinary to me.

Is this the one that has the pedal built in? What's the sense?! You
can buy the pedal and use it with ANY amp. The Blackstar HT series is
another amp with a pedal built into it. And so are a lot of Marshalls,
when it comes down to it.


>
> Tony D
>
>

[Charmed Snark]

RichL expounded in
news:KfidnXYGMYvU8ibT...@supernews.com:

> "Charmed Snark" <sn...@cogeco.ca> wrote in message
> news:Xns9F97F2C5F152DS...@88.198.244.100...
>
>> If you're goint to agree 10% THD is ok, then your 100W
>> tube amp would be rated at 150W then (@ 10%THD).
>
> Ah, but that's my point, sort of. My 100 W tube amp isn't
> rated at 10% THD, at least the way people talk about them
> and manufacturers promote them. Usually the data isn't even
> available to consumers.

Yep yep

But that doesn't mean tube watts are different. It's still
just watts, just different measuring _limits_.

As you say, the way "people talk", they are comparing two
different things:

"Your extension cord is crap! My 50 yard extension cord is
longer than your 50 meter cord. Therefore, metric is crap!"

Well, ok then.

(actually I tend to dislike metric too, but for different
reasons)

You have ask - what qualifies as an "amplifier"?

Two essential qualities:

- more signal power out than goes in
- faithfully reproduces the original signal

This then requires us to agree on what "faithful signal"
means. Noise output instead of signal output disqualifies it
as an amplifier straight away-- so both aspects of the above
are essential.

It is well accepted that the faithfulness is readily measured
by putting in one sine wave and seeing only one sine come out
(when pure). When distortion is added, harmonics appear in the
output in addition to the fundamental.

So THD really is a good measure of this quality of "signal
faithfulness".

So measuring one amp against another with different levels of
"signal faithfulness" is not a strained comparison. At best,
it is a compromised comparison.

HOWEVER:

I will grant that a musician will often substitute the idea of
"sounds good" for "signal faithfulness". But how do you
measure "sounds good"?

If you accept this vague unmeasurable unit, then how do you
agree on _any_ level of tube watts? One musician may say an
amp does 150W good, while another dude might say "that's over
the top at 130W". A Tele picker might say it was over the top
at 102W.

"tube watts" used in this context is a fuzzy term at best. How
can any meaningful result come from this kind comparison? You
might as well just say "I'm happier with tube amp x over ss
amp y".

You could argue further that the technology is not really the
issue here. Just agreement of amp opinion over what "sounds
best".

> I'm wondering how much THD (and how many watts I'm actually
> feeding the speakers) I've got with my AC30 cranked up all
> the way. At that level, as far as "musicality" is
> concerned, the sound being produced is still pleasing, some
> would say extremely desirable!

Actually, the AC30/15 is interesting in the sense that they've
been tarred with the class AB moniker, which might be true.

If it is, the interesting part is that the class AB aspect
produces an added level of distortion of its own. While the
finals are in the class A portion of the signal output, both
halves are contributing output. This doubles the transcondance
in that region and then it returns to unity once the class B
portion of the curve is entered. This causes class AB amps to
produce harmonics without even trying. At lower levels, if it
stays in class A, then this distortion disappears.

>> A competing 0.002% SS amp is perfect up to
>> that 100W limit and then goes ballistic in crap over 100W.
>>
>> But clearly this is no mystery- we're now comparing a 150W
>> tube amp to a 100W ss amp! It's no surprise then that the
>> 150W amp wins. But if you put a 151W ss amp up against
>> it, ss would then win.
>>
>> Watts is watts.
>
> But I'd say that generally, a tube amp described by its
> manufacturers as a 30 W amp (without further clarification)
> is capable of producing more power in a regime defined by
> its users (i.e, guitarists) as "desirable" than a SS amp
> rated similarly by its manufacturers.

This is the very source of the problem. The ratings used on
tube amps are _not_ the same as used for ss. Like yards vs
meters.

For ss it tends to be an absolute and sustainable maximum. For
tubes it ain't. I'm not even certain that tube amps exceeding
the ratings are that sustainable. You might get away with it
given the breaks in the playing and between songs.

Snark.

[Tony Done]

"Jim" wrote in message
news:R6qdnSkyZJQAiiHT...@posted.isomediainc...

I play my Epi VJ fairly clean, about 9 o'clock on the volume knob with the
12dB L-pad engaged, and the Ibanez didn't seem any louder.

The (1996?) BD still has the stock 12" speaker AFAIK, and the H&K has the
12" Eminence Rockdriver Cream. The limitation with the BD is that it seems
to compress more as you turn the clean volume up, and I think in terms of it
being maybe 5w. You could be right about it needing more oomph at the front
end - I recall once it was ear-splitting when I accidentally engaged a
booster. I don't know how clean it was though, I didn't leave it on long
enough to find out.

The TS amp has a built-in TS that seems to be a functionally separate front
end. This whole business of integral FX seems daft to me, just more to go
wrong and limited choices. If I wanted that kind of thing is would either be
a pedal board or digital multiFX.

Tony D

[Tony Done]

What Snark seems to forget is that the guitar amplifier is an extension
of the guitar. The amp IS a musical instrument, just like the guitar.

*********************

And that, IMO is a key issue. The instrument is pickups, amp, guitar,
arguably in that order - though in any argument I would place the guitar
last.

Tony D

[Jim]

Tone-wise, I pretty much agree. For distorted, amp tone overpowers
pickup at some gain level. And you left out a very important link in
the "tone chain"... Speakers, but that might be because you play mainly
combos. Practically speaking, the guitar becomes very important because
it's the most interactive link. It's gotta feel right!

I'm doing my best to not argue what is not really important (bench test
drag races between SS and tube amps).

Here's what I think is important: Is THIS amp going to feel right and
sound right for what I want to hear at this moment? There's no need to
assign that a specification that can be published or plotted on a graph.

Every amp that I own (which is more than I want to admit) sounds and or
feels different. Otherwise, I'd be happy with ONE amp. I currently own
two solid state (early Polytone 102 and a Lab Series L-5). They have
their own positive qualities, even if they don't fall into the "you're
gonna have to pry it out of my cold, dead fingers" category.

You CAN say one amp is "better" than another...depending on your
immediate mood and goals. And you don't need to quantify that with a
published specification. Just like you can say "my Strat is better
suited than my Les Paul" for THIS song, or this mood.

[Charmed Snark]

Tony Done expounded in news:j9h9t1$fim$1...@dont-email.me:

I'm not disagreeing with choice in tone. I was talking to the
point of "watts comparison"- the ever popular concept of "tube
watts" vs "ss watts".

How does this translate to forgoing taste in tone?

Snark.

[Charmed Snark]

Jim expounded in
news:mcednSO9le0LiyHT...@posted.isomediainc:
..

>> For solid state devices, the onset of clipping is abrupt,
>> and most of us would agree that a SS amp driven beyond
>> clipping sound harsh and unpleasant; you don't want to
>> take a SS amp there!

Again this is because this is the absolute maximum rating for
the ss amp. It's not a defect. You've taken that amp where it
is not designed to go.

To handle this situation is quite trivial however - you simply
buy/rent/use a ss amp with the necessary head room. Then
you'll have no unpleasant surprises.

We all agree that a tube amp has more "usable" head room. Tube
amp ratings do not represent absolute maximums.

Snark.

[the_cat]

> > Discuss.- Hide quoted text -
>
> - Show quoted text -

The bottom line is "Listen to it" They could call anything xxx watts
measure xxx ways ( was that with a Strat or lespaul or Tine
gererator ??) . But it doesn't matter at all.. Just listen to it .
( Amp A to amp B side by side if possible.. if you like it and it
fits your need, buy it, if not keep looking. it's not rocket science. e

[RichL]

"Charmed Snark" <sn...@cogeco.ca> wrote in message

news:Xns9F998FAF99B58S...@88.198.244.100...

> You have ask - what qualifies as an "amplifier"?
>
> Two essential qualities:
>
> - more signal power out than goes in
> - faithfully reproduces the original signal

Disagree with # 2 for a guitar amp. And this is the essence of the
disagreement, I think. We talk about THD as if it's a *bad* thing, and in
an amp that's intended to faithfully replicate the original signal, it
certainly is. In a guitar amp, most folks would say it is not, that the
distortion produced by overdriven tubes is desirable. The amp becomes a
part of the "instrument" taken as a whole in that it imparts its own unique
characteristics to the sound. If faithful reproduction is the goal, why
then the arguments about EL34/84 vs. 6L6/6V6 etc?

>
> This then requires us to agree on what "faithful signal"
> means. Noise output instead of signal output disqualifies it
> as an amplifier straight away-- so both aspects of the above
> are essential.

But even there, a certain degree of noise is acceptable to a guitarist
especially in a regime where you can't get the desirable distortion without
it.

>
> It is well accepted that the faithfulness is readily measured
> by putting in one sine wave and seeing only one sine come out
> (when pure). When distortion is added, harmonics appear in the
> output in addition to the fundamental.
>
> So THD really is a good measure of this quality of "signal
> faithfulness".

And is therefore irrelevant to a guitar amp!!

>
> So measuring one amp against another with different levels of
> "signal faithfulness" is not a strained comparison. At best,
> it is a compromised comparison.
>
> HOWEVER:
>
> I will grant that a musician will often substitute the idea of
> "sounds good" for "signal faithfulness". But how do you
> measure "sounds good"?
>
> If you accept this vague unmeasurable unit, then how do you
> agree on _any_ level of tube watts? One musician may say an
> amp does 150W good, while another dude might say "that's over
> the top at 130W". A Tele picker might say it was over the top
> at 102W.

Granted it becomes more difficult to quantify, but so what? Musicians use
their ears! Tele pickers play Fender Twins. People talk about things like
"clean headroom", and if they like clean sounds, they'll pick amps that have
a high "clean headroom" ceiling, like Twins. Others not so much.

SS amp players will spend $$$$ to purchase pedals that try to make their
amps sound like distorted tube amps. If that's not evidence that guitarists
are willing to take a tube amp well beyond the THD range that the audio
purist would consider unacceptable, I don't know what is.

>
> "tube watts" used in this context is a fuzzy term at best. How
> can any meaningful result come from this kind comparison? You
> might as well just say "I'm happier with tube amp x over ss
> amp y".

Granted, but the underlying concept is that traditional ratings of
amplifiers in terms of power output at a given THD level is essentially
meaningless to guitarists.

A 30 W tube amp doesn't behave the same way when used as a guitar amp as a
30 W SS amp. That's the underlying reality. And given that reality, if a
discussion of tube vs. SS amps takes you into a world where quantitative
figures of merit become less relevant, so be it.

>
> You could argue further that the technology is not really the
> issue here. Just agreement of amp opinion over what "sounds
> best".

Clearly, if you want a totally clean sound ("faithful reproduction"), as
some jazz and country folks might want, the traditional THD-based
comparisons would apply. But that's just a small proportion of the world of
guitarists. To the rest, the tube amp is the holy grail *because* of its
distortion characteristics (as I said, check out all the distortion pedals
available that try to mimic it).

>
>> I'm wondering how much THD (and how many watts I'm actually
>> feeding the speakers) I've got with my AC30 cranked up all
>> the way. At that level, as far as "musicality" is
>> concerned, the sound being produced is still pleasing, some
>> would say extremely desirable!
>
> Actually, the AC30/15 is interesting in the sense that they've
> been tarred with the class AB moniker, which might be true.
>
> If it is, the interesting part is that the class AB aspect
> produces an added level of distortion of its own. While the
> finals are in the class A portion of the signal output, both
> halves are contributing output. This doubles the transcondance
> in that region and then it returns to unity once the class B
> portion of the curve is entered. This causes class AB amps to
> produce harmonics without even trying. At lower levels, if it
> stays in class A, then this distortion disappears.

Most guitar amps that have more than one power tube aren't Class A
throughout their operating ranges. They're "push-pull" so most of them will
get into that Class AB regime at some point. But even a true Class A amp
will distort, the difference is you'll get even-ordered harmonics because of
the symmetry.

>
>>> A competing 0.002% SS amp is perfect up to
>>> that 100W limit and then goes ballistic in crap over 100W.
>>>
>>> But clearly this is no mystery- we're now comparing a 150W
>>> tube amp to a 100W ss amp! It's no surprise then that the
>>> 150W amp wins. But if you put a 151W ss amp up against
>>> it, ss would then win.
>>>
>>> Watts is watts.
>>
>> But I'd say that generally, a tube amp described by its
>> manufacturers as a 30 W amp (without further clarification)
>> is capable of producing more power in a regime defined by
>> its users (i.e, guitarists) as "desirable" than a SS amp
>> rated similarly by its manufacturers.
>
> This is the very source of the problem. The ratings used on
> tube amps are _not_ the same as used for ss. Like yards vs
> meters.
>
> For ss it tends to be an absolute and sustainable maximum. For
> tubes it ain't. I'm not even certain that tube amps exceeding
> the ratings are that sustainable. You might get away with it
> given the breaks in the playing and between songs.

Folks do it all the time, though!

[Pt]

On Nov 10, 12:23 pm, Jim <ask@first> wrote:

> > Discuss.- Hide quoted text -
>
> - Show quoted text -

How bout shortening your posts...
Nobody wants to read 87 paragraphs.

Pt

[Pt]

On Nov 10, 3:25 pm, the_cat <esham...@yahoo.com> wrote> The bottom

line is "Listen to it" They could call anything xxx watts
> measure xxx ways ( was that with a Strat or lespaul or Tine
> gererator ??)

Is that a fork prong?
Or maybe part of a tuning fork?

Pt

[Tony Done]

"Charmed Snark" wrote in message
news:Xns9F99A582D4177S...@88.198.244.100...

<g> I'm not buying into that. However, I tried electric guitars on and off
for about 40 years without sticking to any of them, in the foolish belief
that a cheap little SS amp would suffice, and that the guitar was important.
Then I bought a Peavey Classic 30.......

My music is fairly old fashioned and I put great store in mojo, so tubes
have got more going for them than just tone.

Tony D

[the_cat]

Very BAD typo day .. sorry.
If yer pant legs flap when you play a power chord . you have lotsa
waTTs . e

[Squier]

depending on which band I am playing with - live gigs can turn
into just as much an auditory sensation as an actual physical sensation.
There's a point when you just hear the music and then cross over that
with a little more volume and you literally feel the music as much
as you can hear it. Most of the times we play at volumes that don't
get you into that physical realm -- but in one band I am in and when
we're playing outside events - that's when I can really feel it.
Our bass player brings the 2 4X10 cabs and stacks them and you
can feel the bottom ending thumping through your body.
I bring 2 2x12 cabs and stack them and run my 60watt Fender Prosonic head
cranked up and you can feel that pushing through your body.
I don't get to do it many times - but it's a whole different thing
when it happens. It is like the guitar is 'alive' and I can get
perfect harmonic feedback (moving towards the cabs) and it's just
a great feeling to play this way. The notes and chords jump out
and it makes me play differently (in a good way).
It is so much different than playing at lower volumes or going direct into board
(which is my least favorite way of playing).

[Charmed Snark]

RichL expounded in
news:d7qdnYRqQfKc1yHT...@supernews.com:

> "Charmed Snark" <sn...@cogeco.ca> wrote in message
> news:Xns9F998FAF99B58S...@88.198.244.100...
>
>> You have ask - what qualifies as an "amplifier"?
>>
>> Two essential qualities:
>>
>> - more signal power out than goes in
>> - faithfully reproduces the original signal
>
> Disagree with # 2 for a guitar amp.

I know where you're going with this..

But some level faithfulness is mandatory- otherwise it
wouldn't be an amp at all, let alone a guitar amp.

For example, imagine an amp that produced CB chatter- it would
not qualify as an amplifier! It might qualify as a CB
receiver.

10-4?

> The
> amp becomes a part of the "instrument" taken as a whole in

Ya ya ya and I'm not disagreeing as to the component's
usefulness nor its tonal abilities. Nobody is making that
argument.

But the bare statement "tube watts > ss watts" is just wrong.
Artists can flower power it as much as they want, but leave
the watts out of it.

>> This then requires us to agree on what "faithful signal"
>> means. Noise output instead of signal output disqualifies
>> it as an amplifier straight away-- so both aspects of the
>> above are essential.
>
> But even there, a certain degree of noise is acceptable to
> a guitarist especially in a regime where you can't get the
> desirable distortion without it.

Let's ask a different question. How much distortion does it
take before the guitarist says that the amp output is "NFG"?

Everything has a limit. Can we agree on what that limit is?

Nope. More flower power.

>> If you accept this vague unmeasurable unit, then how do
>> you agree on _any_ level of tube watts? One musician may
>> say an amp does 150W good, while another dude might say
>> "that's over the top at 130W". A Tele picker might say it
>> was over the top at 102W.
>
> Granted it becomes more difficult to quantify, but so what?
> Musicians use their ears! Tele pickers play Fender Twins.
> People talk about things like "clean headroom", and if
> they like clean sounds, they'll pick amps that have a high
> "clean headroom" ceiling, like Twins. Others not so much.

So if different muscians can't agree, then just how many
"ss watts = 1 tube watt"?

You won't get universal agreement. Ever. It is an artifical
fluffy Mr. Rogers thing at best.

Maybe that statement works like this instead:

"Tube amps have more flower power than ss amps"

Now that, I will AGREE with!!

> SS amp players will spend $$$$ to purchase pedals that try
> to make their amps sound like distorted tube amps.

There are lots of tube distortions you'd _NOT_ want to use as
well. Not all tube distortions are attractive.

The cuttoff characteristics of most tubes are harsh enough to
avoid. People like the overdriven grid characteristic but not
the cutoff. On the cutoff side, tubes and ss have a lot in
common.

> If
> that's not evidence that guitarists are willing to take a
> tube amp well beyond the THD range that the audio purist
> would consider unacceptable, I don't know what is.

I have _never_ ever argued _that_ point. So why does this keep
coming up? Read my lips...

> but the underlying concept is that traditional
> ratings of amplifiers in terms of power output at a given
> THD level is essentially meaningless to guitarists.

If they don't understand a watt is and how ratings are
measured, then is it wise to teach other folks that these
"tube watts" are somehow different? It might be a suitable
white lie for a child but..

Or should we just agree and pass another joint?

> To the rest, the tube amp is the holy grail *because* of
> its distortion characteristics (as I said, check out all
> the distortion pedals available that try to mimic it).

Actually a large percentage use ss to produce the distortion,
at the preamp level. Very few distortion pedals involve a
tube. This is something folks keep forgeting about. Yet ss
isn't a problem there, is it?

> Most guitar amps that have more than one power tube aren't
> Class A throughout their operating ranges.

There are very few class A amps of _any_ size. They're
horribly inefficient so they don't really apply as far as I am
concerned. You won't find many class A guitar amps. Class A is
prevelant for transistor radios with < 1 watt etc. but not in
the big..

> They're "push-pull" so most of them will get into
> that Class AB regime at some point.

You have to be careful with the "push-pull" term. An amp with
two active devices can operate in push-pull and be class A. It
all comes down to how they are biased.

Depending upon bias, and ignoring class A (too inefficient),
this leaves Class B or AB. The class B is the most common. It
requires that the NFB cancel out the crossover distortion, and
the rest is done by a small amount of bias. The NFB is
actually wonderful in this respect. Class B is the cleanest,
except for class A.

Class AB is the similar to class B, except that the bias
levels are increased such that both halves of your push-pull
design are pulling together during that cross over region (but
not as much as class A where both operate 100%). Because of
this, you have double the normal transconductance (gm) in that
crossover region.

You don't have to take my word on this- I can recommend two
very good books written by expert amplifier engineers, that
speak to this point. When the signal leaves the class-A region
and moves into the class-B region, the gm returns to unity
(only one half of the push-pull arrangement is now involved).
This causes the extra distortion. Again, two engineers I have
recently read, speak to this very point.

This is why in high power amplifiers, you want a suitably
adjusted class-B with NFB. Some guitar amps do away with NFB,
which might be musically distorted, but this is very bad news
for eliminating crossover distortion.

> But even a true Class A amp will
> distort, the difference is you'll get even-ordered
> harmonics because of the symmetry.

Actually, asymmetry is the actual cause of 2nd and even order
harmonics. You have it backwards. Try it out in LTspice if you
don't believe me. ;-) A symmetric wave will not have a 2nd (or
even order) harmonics.

A ss class A amp using a good design with NFB, will have the
lowest levels of distortion of them all (hifi in the extreme).
I don't have my books with me presently but they are way lower
than 0.002% (I think another order of magnitude less). You'd
never ever hear it in any case.

Class B ss, with NFB, properly designed are the next best
thing and are able to produce 0.002% THD and slightly less.
Even lower is possible if you take some subcircuits to the
extreme. If you like, I can point you to some excellent reads
on this.

Class AB is the worst of the above, because of the gm doubling
in the class A region. Therefore, no self respecting hifi will
use it. G amps have flower power, so that makes them more
tolerated.

>> For ss it tends to be an absolute and sustainable maximum.
>> For tubes it ain't. I'm not even certain that tube amps
>> exceeding the ratings are that sustainable. You might get
>> away with it given the breaks in the playing and between
>> songs.
>
> Folks do it all the time, though!

Tubes burn off their cathode coatings, melt and twist their
plates, and otherwise totally burn up. Output power
transformers smoke and cook. Power transformers burn up also.

Tube amp failures happen all the time too. ;-)

Snark.

[Craig 'Lumpy' Lemke]

Charmed Snark wrote:
> Maybe that statement works like this instead:
>
> "Tube amps have more flower power than ss amps"
>
> Now that, I will AGREE with!!

My pentatonic solos just sound bluer with tubes
than with sand. My bedroom walls agree.


Lump

[the_cat]

On Nov 11, 3:57 pm, "Craig 'Lumpy' Lemke" <lu...@LumpyMusic.com>
wrote:

Only a nutball .. bweeb / nerd - would look under the hood or read
the manual to decide if something sounded good. This whole thread is
crazy talk. I'm currently running a Fender Champ 1x10 ss and my JMP
MKII ( tuber) in stereo. cause the combo of both sounds good ( w
volume pedal on the marshall to fade in the nasty when needed). I
could give a rats ass what the specs say.. e

[Craig 'Lumpy' Lemke]

the_cat wrote:
> Only a nutball .. bweeb / nerd - would look under the hood or read

> the manual to decide if something sounded good...

Even nutballier would be for other nutballs to predefine
what kind of equip some new player would need.

"Must have semi pro equip" etc.
Might as well say "we don't really care how you play
but you must have a tube amp that goes to 11"


Lump

[Charmed Snark]

Tony Done expounded in news:j9i32t$ce1$1...@dont-email.me:

> I'm not disagreeing with choice in tone. I was talking to the
> point of "watts comparison"- the ever popular concept of "tube
> watts" vs "ss watts".
>
> How does this translate to forgoing taste in tone?
>
> Snark.
>
> <g> I'm not buying into that. However, I tried electric guitars on
> and off for about 40 years without sticking to any of them, in the
> foolish belief that a cheap little SS amp would suffice, and that the
> guitar was important. Then I bought a Peavey Classic 30.......
>
> My music is fairly old fashioned and I put great store in mojo, so
> tubes have got more going for them than just tone.
>
> Tony D

Tubes in musician circles reminds me of the old computer adage of long
ago "nobody gets fired for buying IBM".

I will agree it "works" and possibly is the easiest way to get that
certain tone.

But I have to believe (perhaps unwisely) that ss's time, even in musician
circles, _is_ coming. I've never been one to follow the crowd on much of
anything.

Snark.

[Charmed Snark]

the_cat expounded in news:2ef6435a-d070-4ac3-aefb-2e9be44e4c75
@u28g2000yqb.googlegroups.com:

Nutballs know how to read manuals?

I think its time to kick some sand at the t00bes!

Snark.

[RichL]

"Charmed Snark" <sn...@cogeco.ca> wrote in message

news:Xns9F9A9D8A82996S...@88.198.244.100...

> RichL expounded in
> news:d7qdnYRqQfKc1yHT...@supernews.com:

>> To the rest, the tube amp is the holy grail *because* of
>> its distortion characteristics (as I said, check out all
>> the distortion pedals available that try to mimic it).
>
> Actually a large percentage use ss to produce the distortion,
> at the preamp level. Very few distortion pedals involve a
> tube. This is something folks keep forgeting about. Yet ss
> isn't a problem there, is it?

Depends on who you talk to. I prefer the real thing. And when I do use a
pedal, it's likely to be one of the following:

-- Radial Tonebone Classic (uses a 12AX7 tube in "starved plate" mode)
-- Keeley Java treble booster (Ge transistor is the "meat", has a more
gradual transition to clipping than Si, and is intended to drive a tube amp;
sounds terrible with a SS amp)
-- Digitech Brian May pedal (digital processing).

[the_cat]

> Snark.- Hide quoted text -

>
> - Show quoted text -

Hmm - I'm mostly a tubie!! and Non-digital to boot... but the lil
champ sounds great as a semi cleanish keep the volume DOWN .. backdrop
to everything ( and I spice it up as needed w the Marshall @ 2x12).
And thats the point I'm using it for and serves its purpose ( even if
it is ss & 15w??). My fav is still the Marshall alone or w the Hiwatt
but they both need plenty of room to breath properly..so, "use what
you need to get what you're looking for" could apply to many things.
ed

[Pt]

Back in the 60's SS amps were the rage.
Especially for me since I was going to school for electronics.
Let me revert...
Before the Rolling Stones came out with "Satisfaction" distortion was
frowned on.
The players I knew, including myself wanted Clean.
I had many bigger Fender tube amps and I was glad to see hi wattage,
light weight SS amps coming around.
I bought a Gibson SS amp which was advertised as a bass amp head and
cabinet.
It was loud and clean.
In a few years most players wanted Marshall's, Hi Watt's and Orange
tube amps because they put out harmonic distortion.
But to get that distortion you have to play at ear bleeding volumes.
By the 70's people were using both SS and tube amps.
SS amps became more affordable and they were very popular with
jazzers, soft rockers and blues players.
I still love BB King's sound and through most of his career he used a
Sun or Acoustic (brand) SS amp.
I had a Roland JC 120 for awhile.
Best SS amp in my opinion but it was very heavy and noisy.
These days SS amps are trying to emulate tube amps with digital
modeling.
I feel that is a lost cause.
You can't make an amp what it ain't!
It is what it is.
The only SS amps I have today are a Behringer V-Tone 15 watt SS amp.
It is a great little amp.
Mic'ed through a PA it can sound much like an old class A tube amp
using EL84's.
My PA is solid state and I play acoustic/electric through an acoustic
DI then through the PA.
Can't beat that SS sound for acoustic instruments.
Good SS amps have their place as do good tube amps.
It all depends on what you want to sound like.
The most important factors in buying an amp are watts and weight.
You want the highest wattage and the lightest amp.
That is an oxymoron.

Pt

[Tony Done]

"Charmed Snark" wrote in message

news:Xns9F9AF18E5814BS...@88.198.244.100...

I think musos might completely bypass analog SS and go straight to digital
if the tube thing ever loses its appeal. Digital envelope followers like
reverb are already very good IMO - after all that is just a similar
technology to digital recording.

I'm not anti-SS by any means, and in fact I have wondered whether I would be
better off with something like a keyboard or pedal steel amp that has a lot
of clean headroom - I'm tending more and more to try and get acoustic tones
out of an electric.

Tony D

[the_cat]

On Nov 12, 2:54 pm, "Tony Done" <tonyd...@bigpond.com> wrote:
> "Charmed Snark"  wrote in message
>
> news:Xns9F9AF18E5814BS...@88.198.244.100...
>

> Tony Done expounded innews:j9i32t$ce1$1...@dont-email.me:

> Tony D- Hide quoted text -

>
> - Show quoted text -

Digital has the additional problem of figuring out whats happeneing
( time delay), and then chopping it into a sample staircase (pieces
missing) & then do whatever you want with it.. So as time marches on
and we keep making computers faster with higher sample rates we will
eventually get so close you won't be able to tell - but its not there
yet (to my ears). I still like tubes and 100 octane gas..ed

[Tony Done]

"the_cat" wrote in message
news:a1a62f09-6166-4ee8...@u28g2000yqb.googlegroups.com...

****************

I don't think you can tell now. Any technology that is good enough for
recording and playing back both sight and sound to a high quality is IMO
certainly good enough for amplifying and modifying musical tones. From my
own experience, latency was much more of an issue than sampling rate on my
old computer. Presumably that is also becoming a non-problem, particularly
in dedicated amplifying devices.

Tony D

[Charmed Snark]

RichL expounded in news:BqOdnZQqwoU-lCPT...@supernews.com:

> "Charmed Snark" <sn...@cogeco.ca> wrote in message

..

>> Actually a large percentage use ss to produce the distortion,
>> at the preamp level. Very few distortion pedals involve a
>> tube. This is something folks keep forgeting about. Yet ss
>> isn't a problem there, is it?
>
> Depends on who you talk to.

Of course there are different preferences.

> I prefer the real thing.

Um, it is the real thing. It's just a matter of do you want ss distortion
or tube distortion. :)

> And when I do
> use a pedal, it's likely to be one of the following:

> -- Keeley Java treble booster (Ge transistor is the "meat", has
> a more gradual transition to clipping than Si, and is intended to
> drive a tube amp; sounds terrible with a SS amp)

There's a lot of ways to get "more gradual clipping". Ge is not the only
trick in town. You can use:

- Si diodes in series
- diode arrangements with resistances (Marshal et al)
- use LEDs instead of regular signal diodes

I haven't done the sales research but I expect that just about every
eguitarist is going to own at least one distortion pedal. Probably more,
owing to that pursuit of that special tone.

> -- Digitech Brian May pedal (digital processing).

Like Ed said, I'm not yet sold on digital processing. The DSPs need
higher sampling rates to take the "crappiness" out of the result. They
seem to do wonders as an earphone amp. But taking it to recording or to
loud levels, it just doesn't seem as good. But they are getting better.

Snark.

[Charmed Snark]

Pt expounded in news:0d8bbb3d-5e2c-4b8e-96fd-239bbd519b22
@n6g2000vbg.googlegroups.com:

> Back in the 60's SS amps were the rage.
> Especially for me since I was going to school for electronics.
> Let me revert...
> Before the Rolling Stones came out with "Satisfaction" distortion was
> frowned on.
> The players I knew, including myself wanted Clean.

From what I've read, engineers didn't really "get it right" with ss amps
in that time period. There were two main problems:

- the tendancy to use ss in the same designs as used for tube amps
- availability of complimentary power transistors (NPN & PNP)

The ss technology was new, so using tube designs with an output
transformer seemed like the correct approach. But this was later
determined to be misguided.

In 1956 Mr. Lin of RCA had already developed the three stage topology for
amplifiers. Amplifiers not based on the Lin topology are for the most
part, not considered "high performance" amplifiers. 99% of amplifiers
made today use this Lin topology[1].

The problem was that in the 60's the necessary complimentary power
transistors were not available (NPN and PNP). You would have one kind or
the other, but you needed both NPN and PNP to make a push-pull design
(there is now a known way to cheat this).

The three stage design amounts to this:

- input stage is a transconductance amplifier (voltage to current)
- the driving stage is a voltage amplifying stage (current to voltage)
- the output is the power stage, as a class-B "buffer"

Since there is a large element of negative feedback in this design, the
input stage is normally a differential amplifier. The signal goes into
one side while the NFB goes into the other. The difference gets amplified
by the voltage amplifier and sent to the power stage.

From a design pov, there really isn't much to improve in ss amplifiers.
The design has been perfected to a large degree allowing the reproduction
of very low %THD. Where most of the variation seems to be is in the
protection circuits, to keep the trannies from cooking. Also there is
considerable variation in protecting the speaker (in case a tranny shorts
out).

There is now a lot of interest in the different kinds of power FETs
available. This is something I'll be trying out. They are known to be
less linear than a bipolar, but are easier to protect from destruction.
With NFB, most of the non-linear aspect is nulled out.

This seems like a good place for me to start. :) Plus, in a musician's
amplifier, this is also a good attribute to have. The cost however, is
that I lose some "usable watts" in the process.

[1] The Audiophile's Project Sourcebook: 120 High-Performance Audio
Electronics ... By G. Randy Slone, page 132.

> In a few years most players wanted Marshall's, Hi Watt's and Orange
> tube amps because they put out harmonic distortion.

I have no argument with those looking for that special tone. I'm just
sick of tubes quitting and rattling about. I'm also sick of the cost and
the weight of the transformers.

So I'm in personal pursuit of a suitable ss solution that gives me the
sound I want.

> These days SS amps are trying to emulate tube amps with digital
> modeling.
> I feel that is a lost cause.
> You can't make an amp what it ain't!

Simulation in software is amazing. Using LTspice for example, you can
simulate what happens in analog circuits. Man that is cool.

Eventually, digital will likely be the solution to the magic tone.
Digital will be able to do transformations that are either not possible,
or simply to complex and expensive to do in analog components.

It won't necessarily be the emulation of the "tube sound". I believe that
distortion tone could be improved upon further. In any power chord in
distortion, there are unpleasant harmonics generated, which a digital
process might be able to remove (this would be highly complex- hence need
for speed).

But that technology is barely up to the task at the moment, IMO. Who
knows what another decade or two will bring?

The time may be coming when the next generation looks at our generation
clinging to their tube amps, while they move on to the next
big thing (TM).

> Mic'ed through a PA it can sound much like an old class A tube amp
> using EL84's.

> Pt

And that is another good point. In the end, a lot of stuff is fed through
the PA for the ultimate power boost. So why not do all the tone stuff at
the preamp level and then leave it up to a big clean power boost? If you
do that, the need for tubes goes away.

One of the things people look for in power [tube] amp distortion is that
tone from the magnetic saturation in the OPT. I'd like to try this at
preamp levels someday to see if I can get a similar tone. Instead of
using a big honkin' OPT, use a small magnetic coupling at preamp levels
that saturates. I had considered using the little donuts from the old
computer memories (on ebay), but I don't think you need to get that
fancy.

So many projects, so little time.

Snark.

[Craig 'Lumpy' Lemke]

Charmed Snark wrote:
> There's a lot of ways to get "more gradual clipping". Ge is not the
> only trick in town. You can use:
>
> - Si diodes in series
> - diode arrangements with resistances (Marshal et al)
> - use LEDs instead of regular signal diodes

- 2/3 of an EBC
- Cat whisker
- Shottkeys

Purple shottkeys are best for hip hop.
Gives the most natural hip and the brightest hop.


Lump

[the_cat]

>
> I have no argument with those looking for that special tone. I'm just
> sick of tubes quitting and rattling about. I'm also sick of the cost and
> the weight of the transformers.
>
>>

> Snark.

My 1976 JMP MKII has never broken down (and a few tube changes just
because looking for different tones)& my 1980 HiWatt 400 just lost a
capacitor in the power supply (could happen to anything) & I just
replaced all the original tubes - just because. Now the Hiwatt does
weigh about 90lbs!! (just the head).. E

[Pt]

Shelf life for paper capacitors is 20 years.
I would change all the filter caps in both amps just to be safe plus
it will quiet them down.

Pt

[the_cat]

Both are quiet as a mouse (that can ROAR). I want to keep em original
as possible "they have MoJo Caps!!). Actually the Marshall was gone
through15 years ago.. e

[Charmed Snark]

Craig 'Lumpy' Lemke expounded in
news:j9plpv$6ek$1...@speranza.aioe.org:

Tunnel diodes are used by the underground movement.

Snark.

[Charmed Snark]

the_cat expounded in
news:794a6fe1-98da-4205...@r28g2000yqj.googlegr
oups.com:

>>
>> I have no argument with those looking for that special
>> tone. I'm just sick of tubes quitting and rattling about.
>> I'm also sick of the cost and the weight of the
>> transformers.
>>
>>>
>> Snark.
>
> My 1976 JMP MKII has never broken down (and a few tube
> changes just
> because looking for different tones)

Consider yourself lucky man.

> & my 1980 HiWatt 400
> just lost a capacitor in the power supply (could happen to
> anything)

Yep, 'lytic caps don't last forever.

> & I just replaced all the original tubes - just
> because. Now the Hiwatt does weigh about 90lbs!! (just the
> head).. E

Ye-ep!

Snark.

[Charmed Snark]

Pt expounded in
news:7ec183e1-8855-475e...@p1g2000yqh.googlegro
ups.com:

The electrolytics in the power supply are more likely to fail
sooner.

Snark.

[the_cat]

>
> Consider yourself lucky man.
>
>
> Snark.

I have a huge pile of computers that dies, a few ss stereos, and a ss
power amp. Problem with this stuff is .. damn near impossible to get
parts.. and when you go digital with proms and embedded logic the
whole mess gets worse..and you need a zillion line storage scope.. and
patience
& sure I'm lucky ..I'm part Irish!! e

[Charmed Snark]

the_cat expounded in
news:fb387277-56b8-403e...@t16g2000vba.googlegr
oups.com:

> I have a huge pile of computers that dies, a few ss
> stereos, and a ss
> power amp. Problem with this stuff is .. damn near
> impossible to get parts..

I know what you mean. If you can determine what the part
numbers are, then.. Just getting Japanese power transistors
requires you to resort to ebay sometimes. Then you still don't
know if the part is genuine.

> and when you go digital with
> proms and embedded logic the whole mess gets worse..and you
> need a zillion line storage scope.. and patience
> & sure I'm lucky ..I'm part Irish!! e

I hate electronics in cars for this very reason! Automotive
electronics is the worst for this. And bleedin' expensive.

Maybe I need a 4-leaf clover or sumptin'.

Pretty soon none of us will be in control. Scary that.

Snark.

[the_cat]

>
> I hate electronics in cars for this very reason! Automotive
> electronics is the worst for this.  And bleedin' expensive.

embedded in BLAck tAR JUST TO MAKE IT EASY..

>
> Maybe I need a 4-leaf clover or sumptin'.

gOT ANY kATNIP???

>
> Pretty soon none of us will be in control. Scary that.
>
> Snark.

MEOW...

[RichL]

"Charmed Snark" <sn...@cogeco.ca> wrote in message

news:Xns9F9D82E0C33C1S...@88.198.244.100...

Aren't the "filter caps" the electrolytics in the power supply?

[Jim]

Yup, and they aren't paper.

I could tell similar stories about the flawless reliability of my
vintage tube amps.

And the broken ones that I buy? Sure, some have a bad tube or just need
filter caps. But a surprising number are broken because of bonehead
user errors. Maybe boneheads should only use solid state?

Most of my amps are running tubes from the 1960's. But some are from
the 40's and 50's. "Real" tubes (US, British and German -- not Russian
or Chinese "polished turds") are not as delicate as some people seem to
think.

I recently tested DOZENS of preamp tubes. I rejected 4 or 5. ALL newer
Russian and Chinese! The old U.S., British and German tubes are very
long-lived.

And when an amp fails? It's often nearly impossible to find replacement
parts for solid state. Don't tell me about substitutes! I have a
Polytone that is oscillating because the previous owner put in
substitute opamps. It wasn't designed for them, even if they have the
same pinout.

[Charmed Snark]

RichL expounded in
news:m7ednaDIboVpeFzT...@supernews.com:

> "Charmed Snark" <sn...@cogeco.ca> wrote in message
> news:Xns9F9D82E0C33C1S...@88.198.244.100...

>>> Shelf life for paper capacitors is 20 years.
>>> I would change all the filter caps in both amps just to
>>> be safe plus it will quiet them down.
>>>
>>> Pt
>>
>> The electrolytics in the power supply are more likely to
>> fail sooner.
>
> Aren't the "filter caps" the electrolytics in the power
> supply?

Electrolytics are used in the audio chain of ss circuits also.
Also found in pedals for both power supply filtering and in
coupling.

Snark.

[Charmed Snark]

the_cat expounded in news:a6127673-eabb-4216-a318-
5aecf1...@p9g2000vbb.googlegroups.com:

This place is going to the dogs.

Snark.

[the_cat]

On Nov 15, 1:25 pm, Charmed Snark <sn...@cogeco.ca> wrote:
> the_cat expounded in news:a6127673-eabb-4216-a318-

> 5aecf171e...@p9g2000vbb.googlegroups.com:

>
>
>
>
>
>
>
> >> I hate electronics in cars for this very reason! Automotive
> >> electronics is the worst for this.  And bleedin' expensive.
>
> > embedded in BLAck tAR JUST TO MAKE IT EASY..
>
> >> Maybe I need a 4-leaf clover or sumptin'.
>
> > gOT ANY kATNIP???
>
> >> Pretty soon none of us will be in control. Scary that.
>
> >> Snark.
>
> > MEOW...
>
> This place is going to the dogs.
>

> Snark.- Hide quoted text -

>
> - Show quoted text -

Meooooooooooooooowwwwwwwwwwwwwwwwwwwww- I'm outa here!!!!!!!!!!!!
psssssssssttt

[Sheldon]

"RichL" <rple...@yahoo.com> wrote in message
news:5cmdnTIiiMHsVSTT...@supernews.com...
> Just thinking about some of the posts in the "DIY setup" thread and
> decided to clarify and stimulate discussions (hopefully attack-free)!
>
> How are amps rated? When a manufacturer says a particular amp is a "30
> Watt" amp, what is meant?
>
> First, one stipulation. Amp rated power doesn't mean the power radiated
> acoustically from the speakers. It means power delivered to the speakers.
>
> But let's get more specific. Most honest manufacturers rate an amplifier
> according to the largest output power it can produce without exceeding a
> certain level of total harmonic distortion (THD), and the good ones will
> specify that THD level (usually expressed as a percentage). THD is
> defined here:
>
> http://en.wikipedia.org/wiki/Total_harmonic_distortion
>
> The power rating of an amp depends on the level of THD specified. An amp
> rated at 30 W, 1% THD is louder than one rated at 30 W, 10% THD. That's
> because the amount of distortion (obviously) depends on how hard the amp
> is driven, and for a given amp you reach the 1% THD point at lower output
> power than you do the 10% THD point.
>
> By the way, 1% THD is a typical spec.
>
> So what's all this got to do with "Tube watts" vs. "Solid state watts"?
>
> It's pretty simple, really. What it comes down to is this: musical
> instrument amplifiers can produce power in excess of the power at which
> the THD specification is achieved. For the audio purist, you don't want
> to go past the 1% THD point (some perfectionists would insist on much
> lower THD for accurate music reproduction). But guitarists can tolerate,
> and in fact many would prefer, distortion well beyone the 1% level.
>
> How much beyond? It depends on whether it's a SS amp or a tube amp!!
>
> For solid state devices, the onset of clipping is abrupt, and most of us
> would agree that a SS amp driven beyond clipping sound harsh and
> unpleasant; you don't want to take a SS amp there!
>
> So what's the THD for a SS amp driven to clipping? I haven't done a
> survey, but here's an example of a TI class-D audio power amp:
>
> http://www.ti.com/lit/ds/symlink/tpa3007d1.pdf
>
> The interesting thing here, not peculiar to this particular amp, is the
> following statement, which you will find on p. 12 of the PDF:
>
> "Clipping is typically quantified by a THD measurement of 10%."
>
> Check also the statement following: The power output at 10% THD is 1.25
> times the power output at 1% THD. So a SS guitar amp rated at 30 W at 1%
> THD is putting out 37.5 W if it is on the edge of clipping (i.e., at 10%
> THD).
>
> Now let's look at tube amps. Unlike SS amps, the onset of clipping is not
> abrupt in tube amps; the clipping is said to be "soft" rather than the
> "hard" character of SS amps. Read more here:
>
> http://en.wikipedia.org/wiki/Tube_sound#Soft_clipping
>
> The point is, in tube amps you can go way past the ~10% THD limit
> characteristic of SS amps and STILL SOUND GOOD! Which in turn means that
> for a tube amp rated at 30 W @ 1% THD, you can get well past the output
> power limit of 37.5 W for the SS example described above and still have
> the amp producing sound that's pleasing to the ear!
>
> So, in essence, for a tube amp and a SS amp that are rated the same in
> terms of power at 1% THD, the tube amp is capable of producing more
> "USABLE WATTS" than the SS amp!
>
> How much more? Well, it depends on who's doing the playing, I suppose.
> I'd imagine a jazz guy doesn't want much distortion (despite it being a
> good thing for us rockers), so the distinction between a tube amp and a SS
> amp in terms of USABLE WATTS is probably close to meaningless to him.
>
> But if you find tube distortion to be a positive feature of a tube amp,
> yes, you'll get much more USABLE watts out of a tube amp with a given
> power rating than out of a SS amp with the same rating.
>
> That is all.
>
> Discuss.

Watts are watts and clipping is clipping. They are both the same whether
you have a ss amp or a tube amp. The difference is what happens when a
transistor or a tube clips.

A transistor clips when you push the wave past the point that the wave looks
smooth. The more watts the amp is rated the higher you can get that wave
before it clips, and that's the case regardless of ss or tube. Now, if you
run the signal through a scope you can see the wave clip as the signal
increases -- the top will begin to square off instead of being rounded.

If you have a solid state amp the wave does not clip more abruptly, it clips
with very square sides and what you hear is a harsh, distorted tone that
hurts your ears. A tube amp will clip just the same, but the wave has
curves where the ss wave is squared off. So, if you push a tube amp the
distortion sounds a little "softer" allowing you to work it into your music
without hurting the listeners ears. Of course if you crank it up enough
you'll go deaf, but within reason the tube amp just has a sweeter sound to
most ears. That said, it is possible to design circuitry which smoothes out
the square wave on a clipped signal, and is what you hear advertised as an
amp with more usable watts than it's designed for. NAD has been doing this
for years in their stereos. On the other side it's also easy to design
circuitry that clips the signal harshly and creates even more distortion.

Get your hands on an oscilloscope and you can see what's being described in
this thread. It's pretty cool science.
>

[RichL]

"Sheldon" <she...@XXXXXXXXsopris.net> wrote in message
news:jacd3b$epf$2...@dont-email.me...

Sure, an oscilloscope will show this. However, these days a lot more
musicians own home recording systems than have oscilloscopes. And most
recording software will allow you to expand the time scale on a recorded
track so you can see just a few periods of oscillation. And lo and behold,
you can see the same phenomena that you're describing.

[Jim]

I pretty much agree (recognizing that there are generalizations, and you
aren't saying "all SS amps do...").

And I'll add that if you have a 'scope and signal generator (audio
generator), it's also fun to see what stomp boxes actually do. You need
to look at different frequencies and different levels. But you SEE why
some pedals sound buzzy, and others sound smoother.