Magic or science?
MDHJWH
cute little Leak 20/20.
They did indeed sound 'magical'.The D 70 was the first amp I'd ever
heard get depth of fiel d and ambience right. Subsequently, after
suffering through the early years of crap, I've been seduced just as
much by transistors .
I've asked this question before (on this group I think?) and never
received anything like a reply. Does any science exist that might
explain why so many prefer hot bottles or are vacuum heads just
deluding themselves with the magic of 2nd HD? I'm told the simplicity
imposed by valve circuitry may be involved. Considering how 'sweet' Mr
Pass's Class A (2 only gain stages?) SS monsters sound (to my ear)s
there may be some truth in the later argument. What gives?
TubeGarden
How we talk about what we hear may impress us with ourselves, but, does not
affect what we hear.
It simply does not matter why we like what we like, it only matters that we
like what we hear.
Nobody likes anything for the proper reason. That is meer posing by weak minds.
We like what we hear, and glory to us for it.
Happy Ears!
Al
Alan J. Marcy
Phoenix, AZ
PWC/mystic/Earhead
Patrick Turner
MDHJWH wrote:
I don't think the 2H present in bottle amps is the reason why they sound
so good
because PP amps including the Leak and D70 have mainly 3H and other
odd order thd products since PP circuit cancel out the even order
products.
In any case, even a Leak with its FB will have a typical 0.05% of thd at
loud listening levels, and a quite reasonable low level of imd.
So arguments about thd/imd are pretty meaningless.
Larger amps than a Leak using a quad of output tubes
will have thd levels at the 0.02% at normal listening.
Just mainly 3H and maybe some 2H from a tube preamp,
or the power amp input stages.
There is no crossover thd produced, and what you hear IS
propduced by simple class A circuitry.
In the case of SE amps, which are renowned for their
subjectively accurate and enlivening effect on music that is otherwise
rendered dead
and clinical by a state of the art SS amp, the thd is a lot higher than
with PP,
but still they just "do it" for some folks.
Without me saying a word, the tube amps I make sell themselves.
Ppl listen, and they decide in favour of the bottles, and yet
the SS amps they have are not cheap crap.
If that didn't happen, I'd be out of a job.
I think something subtle is going on, and I don't care to define it,
but it isn't too hard to keep producing amps which "do it".
So its down to the bottles.
I have made a fairly simple class A PP mosfet amp which
sounds to most to be tube like, but not quite there.
There isn't a great deal of difference.
It has a small amount of FB for a SS amp,
but once you go to class A the amount of FB
in any class A circuit is rarely more than 20 dB,
because the class A circuit is inherently linear
with thd low at low level, increasing to a high level at near clipping.
Nelson Pass likes simplicity, and uses class A and little FB,
and he uses mosfets, which have the closest thd spectra to tubes.
But as I said, thd ain't everything...
But the magic does not dissappear when the thd is kept low.
Patrick Turner.
Choky
some sad male specimen's eyes) ya must know what art is- result of some
craft and some soul.
when some amp is made with craft and soul,then amp sings.
anything shorter than that is just piece of metal and ,mainly, sad macho
approach to life ("skill....bla bla","knowledge....blabla", etc )
ps. Tube Garden can tell ya something ,too........
--
--
.........................................................................
Choky
Prodanovic Aleksandar
YU
"don't use force, "don't use force,
use a larger hammer" use a larger tube
- Choky and IST"
- ZM
............................................................................
"MDHJWH" <mdh...@iprimus.com.au> wrote in message
news:808df0f8.03121...@posting.google.com...
TubeGarden
I can only write my truth. If anyone reads it and decides to hook stuff up and
listen, great. If not, I had to try and share this joy.
After you solve the arithmetic riddles, challenge each value with your ears, in
the real circuit, with real music.
It gets better. Eventually ;)
Happy Ears!
Al
PS WARNING: Changing anything changes everything. You are always at the very
beginning ...
Phil Allison
"TubeGarden" <tubeg...@aol.com>
> PS WARNING: Changing anything changes everything. You are always at the
very
> beginning ...
>
** You are not related to Werner Heisenberg by any chance ??
........ Phil
TubeGarden
Well, we breath the same oxygen molecules and drink the same water molecules,
so, yes, we have a special relationship.
Or might have, in the past or the future ;)
Happy Ears!
Al
PS I am not certain we mean the same Werner ...
Sander deWaal
>Hi RATs!
>How we talk about what we hear may impress us with ourselves, but, does not
>affect what we hear.
>It simply does not matter why we like what we like, it only matters that we
>like what we hear.
>Nobody likes anything for the proper reason. That is meer posing by weak minds.
>We like what we hear, and glory to us for it.
That's why I like to use the term " My-Fi" instead of " Hi-Fi".
>Happy Ears!
>Al
Same to you Al(l) :-)
--
Sander deWaal
Vacuum Audio Consultancy
MDHJWH
Pat, I'm sorry to be an ignoramus again but I have a question that
maybe I'm not asking sensibly . Do forgive if I'm talking utter
gibberish.(Heizenberg's theory aside).I've just started attepting to
digest the RCA Radiotron Designer's Hanbook,1953, picked up at the
local market today for $2.For me it's like reading Martian.
Is it possible that a great many tubeheads are loving their amps (both
Class A & AB push -pull) for all the wrong reasons. Maybe their toys
ceased, somewhere along the line, to apply a balanced input voltage to
the three input terminals,and a balanced output transformer connection
to the two plates and are therefore generating large amounts of 2H
that impresses the listeners as very 'musical'?
Ayn Marx
MDHJWH
>
> ** You are not related to Werner Heisenberg by any chance ??
Everyone is related to Mr Heisenberg by chance, even you dear.
M & M A M P31 Aunt Joan.
Patrick Turner
MDHJWH wrote:
> Patrick Turner <in...@turneraudio.com.au> wrote in message news:<3FDD070B...@turneraudio.com.au>...
>
> Pat, I'm sorry to be an ignoramus again but I have a question that
> maybe I'm not asking sensibly .
Never feel sorry that you are ignorant, unless your'e glad you are'.
> Do forgive if I'm talking utter
> gibberish.(Heizenberg's theory aside).
He was a trifle uncertain....
> I've just started attempting to
> digest the RCA Radiotron Designer's Hanbook,1953, picked up at the
> local market today for $2.For me it's like reading Martian.
Or even Jupetarian.
Usually there's a few line of text, then an incomprehensible
formula, then more text, maybe a graph, and so on.
Its triple dutch to most folks.
To get anywhere with such a book, and to understand it all,
one must start at the beginning, and not let oneself proceed even one sentence past
any point where one gets that old feeing, "WTF does that mean".
The team of authors who spent so long producing the book didn't waste
words like we do today on the Net.
Every sentence says a bookfull.
But to really the the thrust of it all, one needs copies of all the reference material
referred to in the lists of references, which are quite numerous.
So without them we are a little unable to get it all.
Nobody has a collection of all the references.
But I have enough books I have acquired to provide some additional basics,
and I did study physics and maths enough to get the basic drift of the RDH4.
Remember that the book was written in an age when books like that could be written, to cover
90% of what was cutting edge technology in fields of radio and audio.
10 years later, such a book would have been impossible, due to the explosion
of electronics wrought by demand and solid state usage, and by expertise being locked down
by secretive patent holders..
>
> Is it possible that a great many tubeheads are loving their amps (both
> Class A & AB push -pull) for all the wrong reasons. Maybe their toys
> ceased, somewhere along the line, to apply a balanced input voltage to
> the three input terminals,and a balanced output transformer connection
> to the two plates and are therefore generating large amounts of 2H
> that impresses the listeners as very 'musical'?
Oh dear. I will have to struggle to describe your mis-interpretations of the scripts
concerning Amplifierus Tubium.
I will take a random order in adressing your vexed notions,
and rely on your intelligence to collate my explanations,
and catch up by careful study over the upcoming holidays.
Walks along beaches are well acompanied with thoughts about
triodes. ( imposible at age 20, but easy at age 50+ )
I don't know how many tubeheads love their amps, but I guess
many do, and may or may not do so because they need to love something,
and preferably something that breathes music into an otherwise dull, boring, and
and stressed life. Some may love Lamborginnis, others Lambrettas,
large motor yachts, or 10' dinghies.
The bad news for you is that only 2 inputs exist at the input end on all amplifiers,
before or since RDH4 was written.
This may seem difficult to understand, since there are often many connections to an amp.
But in 99% of amplifiers we a pair of input terminals, and a pair of output terminals.
Usually, one terminal of the input and one of the output is connected
to one point, called a 0V reference point, ground, or earth.
All input and output voltages are related to this common point.
But if we look closely at an input section circuit of 99% of amplifiers,
we do indeed have THREE connection points of interest.
First is the earth or 0V reference, to which the power supply is related.
Second is the signal source input point from a CD player etc,
Third is the feedback signal input point.
The output of the amp usually has two terminals, between which the
output signal flow.
I need to say something about basic circuits.
Always there are TWO, because two are required to get a circuit,
just like two terminals on a battery are needed to make a flow of electrons
OUT of the negative end of the battery, through a load, perhaps a headlamp on your car,
and then continuing INTO the positive end of the battery.
This flow is back to front, because in early times folks didn't know what electrons were,
and had already decided current flowed from positive to negative,
and the convention became set in people's minds and nerdish engineers were loathe to change.
But many things seem backward in electronics.
The more ohms we have, the lighter the load is for an amplifier, and this idea is opposite
to common sense which would dictate that a lady arriving at a posh hotel
with 59 suitcases is carrying far more luggage than one with just a handbag.
So rule No1:- electronics always means one has to consider some backwards thinking to
gain the mental picture, for usually ideas are determined by mathematical concepts,
rather than what the bellboy says about your luggage.
Meanwhile, back at the amplifier, one terminal at the output is usually
connected to the 0V reference point, as is one terminal of two
coming from the source.
Between the input and output signal, there are devices to
amplify incoming signal which has low voltage and very low current,
to a proportionate facsimile consisting of around 20 times the voltage, and
thousands of times the current, suitable to enable Mozartian signals
to be heard from a speaker.
Let's think of the amplifier drawn as a triangle, like an arrow without a tail,
drawn on a blank page, and pointing to the rhs side of the page.
The corner facing towards or pointing to rhs is the signal output connection.
At the other vertical side of the triangle opposite the output point
are TWO input points for signal.
This triangle represents all the devices and circuit included in the amp,
except the power supply, and that can be represented
by a battery connected fom a line ruled along the bottom of the page
and to a point of power entry on one of the sides of the triangle
which slopes at 30 degrees away from the output point.
The line we draw is our Reference Voltage, 0V, earth line ground line,
or whatever we want to call it.
The speaker load has one connection to the rhs point of the triangle
and 0V.
The signal input has its active lead in connected to
one of the inputs on the lhs vertical triangle side, and its 0V side connected to
the base 0V line for our little triangular amp.
That leaves the remaining input situated below the live input point.
Why is it there?
Its there because the amplifier amplifies the signal which
exists between the two live input terminals.
The live signal input signal from the CD player goes to one input terminal, the other
input has a signal applied which is a fraction of the output signal , derived from a
resistive divider from the output.
The voltage difference between the two signals is what get's amplified.
So in a typical tube amp, the voltage amplification factor
may be 200 times, which means that for 20 volts of output, we need
0.1 volts between those two live input terminals.
The input voltage from the CD player might be 1 volt, between the 0V line
and its one live output terminal.
1v is applied to one of the triangular amp's input, and
if we had a resistance divider to supply 0.9v of fedback signal to the second
live input terminal, we'd get 20 volts of output.
Amps will work with the feedback connected, or not connected, and without
FB, the gain is called the open loop gain; in this case 200,
and the with the FB connected, the gain is called the closed loop gain, and in this case
its 20, because when we connect FB, we close up a circuit loop for a feed back signal to flow.
To understand this a lot better, I suggest you study some very basic modern text
books where you will find all the block diagrams of amplifiers drawn up as
triangles so that the operation is SIMPLE to understand, without
concerns for the details of HOW we connect all the gizmos up.
detail distracts, and clutters a man's mind, and irritates the female mind.
Finally, (for today's lesson), I need to say that second harmonic distortion
is not purposely injected into one of 3 inputs to the amp to make it more musical.
Imagine if we had a music signal flowing from an amp, and we
were to make another signal which contained all the myriad
frequencies of music but at twice their normal frequency.
This is what the harmonic distortion would be if the amplifier produced
second harmonic distortion.
Suppose the level of this "double the frequency copy"
was 1% of the real music signal, and was mixed with the original signal,
and phase related.
That's what 1% 2H thd would be.
We could extract the 2H from the output signal, and amplify it
to play on a speaker, and if compared alone to
a version of the music at 3,4,5,6,7 times the F, it would sound the least objectionable.
But alas, the presence of any device which amplifies
a given signal, with the addition of another version of the music at twice the F
means that we also produce intermodulation distortion,
where we get a whole lot of other tones produced
by the amplifier, which are the sum of the fundementals and harmonics,
so 1H +2H become 3H, and the difference between fundemental, 1H-2H,
which is -1H.And we also get sum and difference tones produced by
between harmonics.
If we had predominantly third harmonic distortion,
we'd get 2H and 4H intermodulation products with the fundemental, 1H.
I suggest what I have said is inadequate to describe the issues of
musicality in amplifiers, since some very musical amps measure so very well,
and the hd and imd are very low,
so musicality does not depend on distortion being present, imho.
I suggest that if you want to understand these issues, you head out to a technical
library, lock yourself in, and don't come out until you could pass some elementary
electronics exams, perhaps held in mid February.
At the beginning of life we rush in, and all our passions are concerned with the sensuous
side of life, clasping the flesh of others to our breast, and chasing bank notes
to rub hold firmly, before spending wildly, seeing the most wondrous of sights, hearing of sound that's loud
and clear, challenging challenges,
and tasting our way through mountains of tucker, while we garnish our careers,
and its the same for judge, a nurse, a brickie, a surgeon, and we learn
be trial and error to make it all happen.
At the end of life, we ask why is it so, and perhaps we have time for the details,
as the sensuous preoccupation fades.
Patrick Turner.
>
>
> Ayn Marx
Chuck Harris
>
> The bad news for you is that only 2 inputs exist at the input end on all amplifiers,
> before or since RDH4 was written.
99% sure she meant the inputs to the two halves of a PP output stage.
Patrick Turner
Chuck Harris wrote:
I think I tried to explain too much.
Nearly all amplifiers have a differential input, even the ones with an SET
input tube with the input to the grid, and the FB to the cathode.
She's now wondering WTF a differential thingemebob is.
In the fullness of time, all the necessary concepts about
audio engineering will become clear to those who
put the days, weeks, months and years into the persuit of understanding.
I found it helped to build and measure sample amps on scrap chassis as I learned.
Electronics requires the ability to grasp mental concepts about how
the many basic things work.
There is a differential in the rear axel of most cars.
It enables them to turn corners without breaking axels.
This takes some understanding, as do the 101 systems in a motor vehicle,
or if you are a doctor, 1,000,001 things about the body.
Patrick Turner.
Chuck Harris
>
> Chuck Harris wrote:
>
>
>>Patrick Turner wrote:
>>
>>>The bad news for you is that only 2 inputs exist at the input end on all amplifiers,
>>>before or since RDH4 was written.
>>
>>99% sure she meant the inputs to the two halves of a PP output stage.
>
>
> I think I tried to explain too much.
Not to worry, she's very bright, and will soon figure out what
she wants to know about tube amps.
-Chuck
MDHJWH
>
> Not to worry, she's very bright, and will soon figure out what
> she wants to know about tube amps.
Not bright in any mathematical sense, in fact I suffer from
discalcula, that maths equivalent of dislexia.
The passage that led me astray is :-"The fundamental circuit of a
push-pull power amplifier is Fig.13.31. A balanced (push-pull) input
voltage must be applied to the three input terminals, and a balanced
(push-pull primary) output transformer must be connected to the two
plates with its centre-tap connected to Ebb+.For the best results the
input voltage must be exactly balanced, the valves must have identical
characteristics and the output transformer must be exactly balanced
between the two sections of the primary, with perfect coupling between
them. Under these conditions, any even harmonics introduced by the
valves will be cancelled, but odd harmonics will not be affected;the
flux in the core due to the d.c. plate currents would be zero."
Radiotron Designer's Handbook1953.page 571.
Of the frightening list of references given at the back of this text
which should a mathematicaly illiterate old bat such as myself attempt
to digest as an introduction to bottle theory?
Ayn Marx
Patrick Turner
MDHJWH wrote:
> Chuck Harris <cfha...@erols.com> wrote in message news:<3fe461c0$0$4749$61fe...@news.rcn.com>...
> >
> > Not to worry, she's very bright, and will soon figure out what
> > she wants to know about tube amps.
>
> Not bright in any mathematical sense, in fact I suffer from
> discalcula, that maths equivalent of dislexia.
> The passage that led me astray is :-"The fundamental circuit of a
> push-pull power amplifier is Fig.13.31. A balanced (push-pull) input
> voltage must be applied to the three input terminals, and a balanced
> (push-pull primary) output transformer must be connected to the two
> plates with its centre-tap connected to Ebb+.For the best results the
> input voltage must be exactly balanced, the valves must have identical
> characteristics and the output transformer must be exactly balanced
> between the two sections of the primary, with perfect coupling between
> them. Under these conditions, any even harmonics introduced by the
> valves will be cancelled, but odd harmonics will not be affected;the
> flux in the core due to the d.c. plate currents would be zero."
> Radiotron Designer's Handbook1953.page 571.
If only you'd mentioned the page ref when I replied to you before.
What the dear Olde Booke does not say is what needs to be said
so dummies could understand.
Wading into the middle of the RDH4 without understanding all the preceeding
pages about audio will certainly puzzle the beginner, just like I was mightily
puzzled once, and certainly like I was puzzled when I tried to replace a stuffed
motherboard in a PC after only having had a PC for 9 mths, and I tried to rely
on a book supposedly able to be understood by dummies.
I eventually replaced the MB OK, but finhal adjustments at settings was done
best by searching gor a good cheap young bloke, who didn't have a clue
what a triode was.
The circuit on page 571 does have 3 input terminals.
There is the centre one which connects to a negative terminal of a battery,
which has a fixed voltage point in relation to the commoned cathodes,
which is the 0V or ground reference voltage mentioned in the long description
I gave in a previous post about representing amplifiers as triangles,
with 0V for the power supply 0V rail, and two
oppositely phased inputs.
The two inputs are the ones that go to the input grids.
It is assumed, but not shown that the grids are connected to a
source which is grounded at 0.0 Hz, so the circuit is biased,
but understanding bias is a whole other issue.
Now if you have 2H distortion applied to each input
of the amp shown, which is oppositely phased, it gets amplified
like the oppositely phased fundemental frequency fed into this PP
output stage.
But if the 2H fed into the inputs was the same phase, it won't get amplified,
and there will be little contained in the output signal.
Same goes fot the signal. If each signal applied to the circuit was the same phase,
no signal comes out.
Only the DIFFERENCE between the two input signals gets amplified.
>
> Of the frightening list of references given at the back of this text
> which should a mathematicaly illiterate old bat such as myself attempt
> to digest as an introduction to bottle theory?
First must come the mental concepts of what amplifiers are,
without the maths understanding, and then come the simple equations
which also describe their operation.
Ohm's law also become sensible AFTER we get to understand current and voltage.
Ohm's law is a simple 3 quantity linear equation.
You may find most of the reference material to which RDH4 refers has been removed of library
shelves decades ago, to make way for modernity.
So a lot of searching for ANY books on electronics written before
1960 is required.
Modern books are useful for the basics, and those triangles I spoke about,
but its hard to translate the modern approach to amplifiers to tube circuits.
The very basic principles are the same.
............................................
Female beauty = Charm x Poise.
Male stupidity = Ignorance x T, where T is the time duration.
Now surely you understand that the beautiful female could
still be beautiful even if she had little charm, but had a lot of poise.
And a really charming lass could be beautiful, even if she was hopelessly clumsy.
A bloke who was extremely ignorant for a short time
is as poorly off if he was only slightly dumb all day.
Most basic electronics is as simple as these "life equations", ie, common sense,
but instead of hairdos, lipstick or makeup, the quantities are electrons,
resistance and voltage levels.
One will never understand any amp if the basics about current, voltage,
resistance, inductance, capacitance remain a mystery.
Once the basics are understood, we can work out where the electrons are flowing,
and what they are doing while they flow.
Patrick Turner.
>
>
> Ayn Marx
Chuck Harris
I suppose it depends on where you want to go with your tube
curiosity. If you just want to have a feeling for how the
amps work, you might want to go one route, and if you want
to learn how to design the amps, you might want to go another.
A good way to get a feel for how the amps work, and how they
are built is to build a simple kit. There are dozens out there,
ranging from the absurdly high priced to very simple. I'm sure
that Patrick could aim you in the direction of some good simple
kits. Do get some one-on-one help with your first kit. Soldering
is easy to learn; but easier to learn if you can be shown how.
If you want to become a designer, the kit route is still a good
place to start, but some more grounding in electronics would be
necessary. A good beginner's text for learning electronic's
principles would be any of the older "The Radio Amateur's Handbooks"
published by the ARRL. Try for something from the 1960's. They
are aimed at the non professional who wants to learn basic
electronics, with the intention of learning how to build. ... The
1960's issues were heavily bent towards tubes. The RAH's are
geared towards RF, but the basics work for all branches of electronics.
After you have digested the electronics basics from the RAH,
and have given yourself a familiarity with the physical aspects of
the parts envolved, you should be ready to start chewing on the
Radiotron Designer's Handbook. It will be a big step, but I think
if you are properly motivated, you can probably make it. I did it
when I was 15-16, so you see it is more a matter of drive than
sophistication.
The RDH should be started at the beginning, and worked towards the
end. This is the kind of reading that requires a pencil and pad of
paper. Read and try, read and try... You should be creating a
loose leaf notebook as you work your way through it. The notebook
should be full of practice calculations, drawings and parts of the
text that you want to remember. Resist the urge to graffiti your RDH,
you will thank yourself later when you better understand the subject
matter. There is nothing more annoying than to have all this stuff
highlighted that once seemed vital, but now is just routine. It makes
me sad when I see what I did to some of my old EE text books.
-Chuck Harris
MDHJWH
>
> One will never understand any amp if the basics about current, voltage,
> resistance, inductance, capacitance remain a mystery.
> Once the basics are understood, we can work out where the electrons are flowing,
> and what they are doing while they flow.
I have a good grasp of the fundamental operations of current, voltage,
resistance, inductance, capacitance (although I must confess that some
of the peculiar discussion I've come across attempting to relate these
to the sound of cables impresses me as nonsense!)
My stumbling block is my inability to grasp mathematical
operations.Anything beyond the simplest quadratic equation freezes my
brain and induces a state of terror. I'm enrolled into a coarse next
year at the local tech, geared specificaly for those who are 'maths
phobic or suffering discalula' Who knows, this time next year I might
be able to stick my toes into electronic theory at last. Not being
able to do so has frustrated me for decades. Pray for my
enlightenement Pat and thanks for your patience and helful
explanations.
Patrick Turner
MDHJWH wrote:
> Patrick Turner <in...@turneraudio.com.au> wrote in message news:<3FE58C97...@turneraudio.com.au>...
>
> >
> > One will never understand any amp if the basics about current, voltage,
> > resistance, inductance, capacitance remain a mystery.
> > Once the basics are understood, we can work out where the electrons are flowing,
> > and what they are doing while they flow.
>
> I have a good grasp of the fundamental operations of current, voltage,
> resistance, inductance, capacitance (although I must confess that some
> of the peculiar discussion I've come across attempting to relate these
> to the sound of cables impresses me as nonsense!)
Hmm, there is both nonsense and sense around...
But if you were aufait with the basics, the PP circuit you mentioned
would have presented not the slightest problem to fully inderstand.
>
> My stumbling block is my inability to grasp mathematical
> operations.Anything beyond the simplest quadratic equation freezes my
> brain and induces a state of terror.
There are few quadratic equations needed by the DIY person.
Most are "3 prong" simple linear equations like Ohms's law.
However, equations about phase angle calculations, and reactive quantities
or anything involving calculus would leave 99% pof the population struggling.
> I'm enrolled into a coarse next
> year at the local tech, geared specificaly for those who are 'maths
> phobic or suffering discalula' Who knows, this time next year I might
> be able to stick my toes into electronic theory at last. Not being
> able to do so has frustrated me for decades. Pray for my
> enlightenement Pat and thanks for your patience and helful
> explanations.
Hopefully a good teacher will lead you to the light.
I know a couple of guys who will NEVER understand Ohm's law,
not ever, even if they lived 10 lifetimes.
One was a hi-fi salesman, the other is a art teacher.
They will NEVER manage to design the simplest of
single stage triode amps, or have the feintest idea exactly what happens
in such a stage. Reading books like RDH4 causes immediate
numbing and paralysis of the brain, and a comatose
condition.
Any talk of phase shift casues a dull blank stare.
Feedback? what the hell is that?
But they got a lot to say about which brand of triode to use,
and the cables that go with the amp, and the box the amp is in,
and the brand of caps, resistors, wiring, etc.
But no clue how it works.
I just smile and agree with them.
I am a hopeless hi-fi salesman,
and I can't teach art.
I can only let the amps sell themselves, and if I had to teach kids about art,
I'd hand them paints and canvas, and tell them to go paint something.
Patrick Turner.
TubeGarden
It is possible some great Art does not exist, yet :)
It is possible to build circuits and hear how it sounds without pretending to
understand how it works ;)
Pimping Hi-Fi is just pimping. It pays some of the bills. It is not important
8^0
Happy Ears!
Al
MDHJWH
>
> But if you were aufait with the basics, the PP circuit you mentioned
> would have presented not the slightest problem to fully inderstand.
speculating about
such things operating incorrectly and therefore generating lots of 2nd
HD to
the joy of their owners.
>
> >
> > My stumbling block is my inability to grasp mathematical
> > operations.Anything beyond the simplest quadratic equation freezes my
> > brain and induces a state of terror.
>
> There are few quadratic equations needed by the DIY person.
> Most are "3 prong" simple linear equations like Ohms's law.
> However, equations about phase angle calculations, and reactive quantities
> or anything involving calculus would leave 99% pof the population struggling.
>
bad at soldering but
a recent inspection of Dick Smiths offerings revealed nothing too
flash. Can you recommend and iron
that will work on small & larger scales and suggest a kit I might
start constructing?
I'd love to put together an FM tuner but I doub't any such kits using
bottles are out there and
if so they would most probably be too advanced. A power amp appeals
but recommening one could be doing yourself out of business Pat. I
suspect the weak point of any such kit would be the quality of the
tranformers. I shant ask Mr you-know-who about those.OOOOH this is
exiting at my age!!!!!!
How much test equipment would I need ? I presume that with valves a
potentiometer capable of workng at high voltages would be necessary?
If I 'm slow to respond over the next week or so it's the 11 plub
puddings and other silly season concerns that are taking my attention
away.All the best for you Christs Birthday Celebrations boys.
Patrick Turner
TubeGarden wrote:
> Hi RATs!
>
> It is possible some great Art does not exist, yet :)
>
> It is possible to build circuits and hear how it sounds without pretending to
> understand how it works ;)
This is indeed possible.
Its a bit like randomly assembing words, and expecting the arrangement
to be a nice copy of the Lord's prayer,
or one of Lenin's speaches....
>
>
> Pimping Hi-Fi is just pimping. It pays some of the bills. It is not important
> 8^0
Now this one I can't figure.....
Patrick Turner.
Patrick Turner
MDHJWH wrote:
> Patrick Turner <in...@turneraudio.com.au> wrote in message news:<3FE63CB1...@turneraudio.com.au>...
> >
> > But if you were aufait with the basics, the PP circuit you mentioned
> > would have presented not the slightest problem to fully inderstand.
> It wasn'tso much that I didn't fully understand the 'circuit'. I was
> speculating about
> such things operating incorrectly and therefore generating lots of 2nd
> HD to
> the joy of their owners.
The basic PP circuit on page 571 rdh4, to which you referred
is common to nearly all PP tube amps.
If the input to each input grid is unbalanced, ie +6v to one,
and -4v to the other, then indeed one tube will try to provide more power to the output than the other, and
2H will be created.
Very unmatched output tubes will have a similar effect, and in fact
rdh4 does cite a case where a 2A3 and 45 are used, see pg 581.
But at low power, the resulting distortion is quite low, and i suggest you read what is said about
matching and effects of mismatching.
Audiophiles strive to keep input voltages balanced, and output tubes matched,
but it is possible to get considerable 2H injected into the output stage from an SET
input tube having to make considerable voltage before the phase inverter stage.
This is commonly done.
Fancy shmancy circuits are liked where where 20volts if created by some SET input
tube, and then sent into an input to a 1:2 tranny, and the 2H is considerable, and
the +/- versions of the 2H is produced at each end of a the secondary winding
which is grounded at a CT.
The resulting 2H at the output is similar to what you'd get from an SE output stage, but don't ask me if
that's what makes the tube sound so appealing.
Most amps with an SE tube produce several times more 2H than the method just described.
Its not uncommon for a genuine SE amp to make 10 times the thd of a PPamp,
all mainly 2H, but less than 0.2 % at normal listening levels.
Arguments that its the 2H that "improve the sound"
are a trifle meaningless to me; I think that's too simplistic an argument.
I am now building a pair of SE 45 watt amps where I will set up
the driver stage so its 2H almost completely cancels the 2H produced in the output stage,
and thd will be LESS than a PP amp up to around 5 watts, which covers all my
listening needs.
I'll have to let you know if that is a better thing to do than
allow copius amounts of 2H to appear at the output.
I suspect i should have some nice amps to listen to, but i cannot be certain until
the fat lady sings.
> > > My stumbling block is my inability to grasp mathematical
> > > operations.Anything beyond the simplest quadratic equation freezes my
> > > brain and induces a state of terror.
> >
> > There are few quadratic equations needed by the DIY person.
> > Most are "3 prong" simple linear equations like Ohms's law.
> > However, equations about phase angle calculations, and reactive quantities
> > or anything involving calculus would leave 99% pof the population struggling.
> >
> It seems the future has me holding a hot soldering iron. I'm not too
> bad at soldering but
> a recent inspection of Dick Smiths offerings revealed nothing too
> flash. Can you recommend and iron
> that will work on small & larger scales and suggest a kit I might
> start constructing?
I use a $20 x 40W chinese iron from a hardware store.
I used to use a Weller mains 40w iron, but they were $60,
and lasted only 12 mths average, being left on a lot everyother day.
The first chinese iron lasted 1 mth, so I returned it, and they replaced it straight away,
even though I'd lost my sales docket, and the one I use now has run OK for
5 mths, so I'm ahead compared to the Weller.
I bet the store pays around $3 for the iron when they import it.
They couls aford to have a failure rate of 70%, but that is not the case, because most
ppl are weekend users, or buy an iron to do one small job, and they last years that way.
A suitable kit is to make a simple triode line stage from scratch, point to point
wiring on tag strips, with say 4 twin triodes on a metal chassis
about 300mm long, 200mm front to back, and 50mm high.
Premade kits teach you to solder someone else's thoughts together,
and saves you using your brain to make the decisions along the way,
so you learn nothing.
I DID make up some basic premade solid state kits , one is a wien bridge oscillator,
which I have mosified beyond recognition to make a low thd oscillator,
with less than 0.002% thd, and another was a frequency counter to count from
2Hz to 50 mHz, and this little item was far more complex than I ever could design,
with quite a few chips within.
Same goes for a mini FM transmitter which gives me left and right channels.
I added a pair of wien bridge oscillators to modulate each channel at various levels.
I made my own volt meter with a high impedance fet input, and
1 mHz of bandwidth, 6 ranges from 10mV to 1,000v,
using all discrete transistor parts.
I got quite familiar with solid state.
> I'd love to put together an FM tuner but I doub't any such kits using
> bottles are out there and
> if so they would most probably be too advanced.
True, no tube FM kits out there, and no tube multiplex decoders either.
No coils and transformers are available.
For that sort of thing, best to upgrade something old, but established.
But the learning curve is quite steep, no doubt about that.
> A power amp appeals
> but recommening one could be doing yourself out of business Pat.
I post enough info to allow diyers to do their own.
A few have managed it, even winding their own OPT's to my recipe.
But this takes enormous dedication.
But I know guys who build aeroplanes and yachts in their backyard.
One did a big yacht, and had to demolish part of the house, to get it to the water.
Then he sailed around the world for years.
> I
> suspect the weak point of any such kit would be the quality of the
> tranformers. I shant ask Mr you-know-who about those.OOOOH this is
> exiting at my age!!!!!!
There is a lot of claimed knowledge about OPTs out there.
And some of the loudest claimers couldn't produce a
workable design even if their life depended on it.
Most folks head for Hammonds.
A few will go to high fallooting types using amorphous cores,
silver wires, etc, and its a moot point if any of these things are better than a well
done grain oriented core with copper wire.
>
> How much test equipment would I need ? I presume that with valves a
> potentiometer capable of workng at high voltages would be necessary?
> If I 'm slow to respond over the next week or so it's the 11 plub
> puddings and other silly season concerns that are taking my attention
> away.All the best for you Christs Birthday Celebrations boys.
Its the time for Family Distractions, of Seasonal Madness, etc....
The test gear needed for serious home builders would include :-
A good set of small hand tools, long nose pliers, screw drivers, side cutters,
allen keys, hammer, popriveter, drills, bench vice, etc, etc.
Oscilliscope, a second hand 20 hHz single trace is the minimum,
An auto ranging digital voltmeter, preferably a Fluke, for around aud $200.
Soldering iron,
Signal Generator, ( or called function generator, or oscillator ) with F ranges from 2 Hz to 2 MHz, with
sine, triangular, and square waves.
Some of the stuff you might buy at Dick Smith or Jacar may not last too long,
especially if you accidently brush the oscillator output against a +350 volt
rail in a power amp, since a back voltage shock to a solid state sig gene
will blow the output devices away in a millisec.
I made a tube cathode follower in a box to buffer the sig gene output,
after blowing up the output transistors 3 times.
I once had my modern Labtech solid state dual trace oscilliscope set to
maximum sensitivity, and managed to send a 2,000 volt
pulse into the input.
I then became an expert on fixing CROs for the next month, and I replaced every chip
on the board, and many discrete transistors, and re-calibrated the darn thing.
I learned the hard way to respect voltage limits.
Test gear wears out.
I have also had a few 500v arm to arm shocks, from being careless,
or just not aware enough.
Most shocks are finger shocks from the mains, from uncovered
mains entries, even though the gear was turned off.
From day one, REMOVE the plug from the wall socket
BEFORE working on the gear.
make sure its the right plug, and the lead isn't some other thing amoungst many
you have plugged in.
5 amp circuit breakers on the bench are a good idea.
And the bench should be as long and wide and as solid as you can afford.
The cheapest stout bench is to get a couple of second hand
solid core timber doors, they are 2mtres long, x 820mm wide,
and can have 100mm square timber legs screwed to each corner
with 4 x 100 mm long screws. Several old tables are OK.
Get the height right.
Sometimes if these are fixed with an angle to the wall it helps.
Buy a pile of flurescent lights, I have about 20 in my shed,
but I also have skylights over the bench, to save lighting power.
You need good light for a workshop, especially if
you are over 35.
I wear an extra pair of reading glasses to work on SS circuits,
but I know guys who use a surgeon's head set, with lenses and lighting.
I did spend years in the shed late at night building things on breadboards, or
on make shift chassis to try things.
I compiled all my test results of circuits in exercise books, because writing up the results
like a carefully done school science project makes a record, and you tend to learn
far better.
I have around 200 x 150 page exercise books full of work notes.
I have distilled these into folders which contain only
those circuits and derived formulas which I know will work.
But the resulting paper files are a metre stack high.
Even today, when I have a horrible complex SS amp to fix,
I draw the circuit out nice and large in my book
to make sure I have got it.
Tubes amps are simple in comparison, but a tubed oscilliscope, or
a tubed organ, such as a Hammond, can present a real challenge to understand,
since the schematic has so many confusing lines running all over the place.
Try understanding a Quad 22 preamp. Its simply not easy.
Electrons just don't allow anyone to be ignorant.
I once copied about 1,000 pages from a copy of Tremains Audio Encyclopedia,
since obtaining a copy was like finding rocking horse dodo.
That exercise cost $100 at 10c per page, took a few days,
and was worth every cent.
I spent weeks in the musty smelling archives at the ANU libraries,
where ancient copies of wireless world lurk in the basements of a couple of buildings.
I read all the audio articles between 1917 to recent times.
I copied lots of tube info.
Don't do anything I wouldn't enjoy over Xmas,
Patrick Turner.
TubeGarden
Any multimeter will suffice. The accuracy of the readings does not affect the
sound :)
My comment about hi-fi sales guys was it is just a job, like bank president or
McDonald's fry cook. Nothing to do with building ultimate ear candy ;)
We each may learn from whatever path we take. Not much point dissing paths not
taken ...
None of us is on the correct path, so, relax and enjoy yours and lighten up on
the others ;)
Chuck Harris
>
> I use a $20 x 40W chinese iron from a hardware store.
> I used to use a Weller mains 40w iron, but they were $60,
I have used an old Weller WTCPN(same as current WTCPT) soldering station
for 20 years, and have only had to replace a couple of soldering tips...
and they weren't worn out, just too high a temperature. These are
available on ebay for $10-$15. For a new iron, I would pick any of the
Weller adjustable temperature stations in the $100 range. They are
controlled temperature, and around 50W of power. This is not a place
to scrimp. You don't want to use any iron that heats with the mains
voltage. They do not last. The good stuff all runs the heaters off
of 28V, and is temperature controlled. A good thin multicore rosin
60/40 solder is a must: Kester, Ersin,... Stay away from anything that
boasts that it is ecological. Wash your hands after work, every time.
>
> Premade kits teach you to solder someone else's thoughts together,
> and saves you using your brain to make the decisions along the way,
> so you learn nothing.
On this I disagree! The act of designing a circuit coming up with the
proper parts, and machining a chassis, and assembling is way too big a
step for anyone to take. This advice is the right advice to give to
someone that you DON'T want to learn about electronics.
A good kit will have a tested circuit, all the parts needed, a punched
chassis, and a simple plan that shows how to wire the circuit.
It is quite enough to go through this process and make your first
working amp. When you are done, you will have a model that you can
listen to, measure and contemplate. If your curiosity allows, you can
try simple changes to see what happens. Since you built the kit, you
can always put it back to the way it was. Kits that are hand wired
are best (eg. no circuit boards!)
>>I'd love to put together an FM tuner but I doub't any such kits using
>>bottles are out there and
>>if so they would most probably be too advanced.
Once upon a time, there was a company called Heathkit. They made a very
nice, simple tube FM tuner Kit. It worked very nicely, and was simple
to get going with very little test gear. But alas they are no more!
A friend gave me one (FM1, I think it was), I deemed it useless, and
tore it apart... Then I rebuilt it from the instructions and used it
for several years... Became a big bad engineer and learned that tubes
were bad, solid state was good.... So I took it apart once more. I wish
I could remember where the parts are, 'cause I'd like to build it again.
> I post enough info to allow diyers to do their own.
> A few have managed it, even winding their own OPT's to my recipe.
> But this takes enormous dedication.
> But I know guys who build aeroplanes and yachts in their backyard.
> One did a big yacht, and had to demolish part of the house, to get it to the water.
> Then he sailed around the world for years.
It's asking rather alot of a newbie to build from your designs, Patrick.
You don't go into the details of some of the simple but important parts,
like power supplies. It is kind of like expecting a baby to do brain
surgery.
>>How much test equipment would I need ? I presume that with valves a
>>potentiometer capable of workng at high voltages would be necessary?
You are using making a common mistake, a potentiometer doesn't read
voltage, but rather is a variable resistance voltage divider.
The sum total of the test equipment necessary to build an amplifier is:
1) a analog volt-ohmmeter with an input impedance of at least
20,000 ohms/volt
2) a simple audio signal generator.
3) an 8 ohm 25W power resistor.... Doesn't matter what kind.
Tools:
1) a good temperature controlled Weller soldering iron.. You can get
by with less, I DON'T recommend it!
2) pointed pliers
3) wire strippers
4) diagonal cutters (commonly called "dikes")
5) good quality flat blade screwdrivers (1/4", 1/8", 3/32")
6) good quality phillips screwdrivers (#2, #1)
7) adjustable wrench 0-1"
A work bench:
1) 36" solid core door with masonite skins
2) a pair of short filing cabinets as legs, or bench leg kit,
boxes, or sawhorses, or ??? your choice.
3) a good flexible clamp on light with shade. "Luxo" style lamps
work nicely. I prefer one with a magnifier built in, cause I
can't see close up anymore.
4) small vise.
Supplies:
1) mostly just a good 60/40 multicore rosin solder. 18 gauge it the
thickest you should use. Kester is a good US brand.
2) a dish with a damp sponge for wiping the crust of the soldering
iron tip.
Plenty more stuff can be found that is useful if this turns out to be
your thing.
As to kits, I thought Patrick could be of help, but I guess he doesn't
go that way.
If you want to roll your own, Antique Electronics Supply has designs,
parts, and everything you need all in one place. The term "breadboard"
comes from the old habit of swiping the wife's wooden cutting board and
building radios, etc. using brass wood screws as terminals, and screws
and bushings to hold up sockets, ... It is a tried and true method, and
works... Very low cost too. Googling "Amplifier kits tube" will show
up a long list of companies that are providing kits. You should be
able to get by for under $400 for something really nice. SET's are easy
to build, but not enough easier to rule out a PP 6L6.
Anyway, you have a bit of thinking to do before you start.
Merry Christmas Ayn,
-Chuck
Sander deWaal
>1) a analog volt-ohmmeter with an input impedance of at least
> 20,000 ohms/volt
>2) a simple audio signal generator.
>3) an 8 ohm 25W power resistor.... Doesn't matter what kind.
I'd add a (simple) oscilloscope.
Doesn't matter what, even a single trace type with 10 MHz bandwidth
should suffice.
On E-bay, they can be found from $25 up.
Without one, you could just as much be deaf and blind when designing
or modifying audio gear.
Imagine designing a lead or lag network without one.....BRRRRRRR!!
Chuck Harris
Agreed, but to build an already tested design, a CRO is hardly
a necessity.
Quite often, a $25 scope can become more of a project than the
project it was intended to help.
-Chuck
Patrick Turner
Chuck Harris wrote:
> Patrick Turner wrote:
> >
>
> > I use a $20 x 40W chinese iron from a hardware store.
> > I used to use a Weller mains 40w iron, but they were $60,
>
> I have used an old Weller WTCPN(same as current WTCPT) soldering station
> for 20 years, and have only had to replace a couple of soldering tips...
> and they weren't worn out, just too high a temperature. These are
> available on ebay for $10-$15. For a new iron, I would pick any of the
> Weller adjustable temperature stations in the $100 range. They are
> controlled temperature, and around 50W of power. This is not a place
> to scrimp. You don't want to use any iron that heats with the mains
> voltage. They do not last.
Pardon my input to the thread.
There were no cheap non mains soldering irons that I could find, which are the stay-hot
variety.
I bet the chinese irons are for 220v, but we had 245v here.
I have a steel box with some dropping resistors to limit the heat, with a switch to
go to a "medium" temperature.
Weller mains irons at aud $60, (us $42) are made here by Cooper Tools,
with a plant in Albury-Wodonga. I sent back the ones that failed, and they sent me
2 replacements they said would not fail but of course they did, within 15 mths.
I asked them for a 12v version of the same iron, so that the heating wires would be
thicker, and less prone to going open, and they said the cost of a transformer is
prohibitive in the Aust market, where folks buy the $20 chinese throwaway iron, like I do
now.
I have stacks of old trannies, and they refused to supply a low voltage iron without
a tranny.
I know guys who have used the same old iron for 20 years,
but like lightbulbs, they are now designed and built by bean counters.
Tips coated with iron only last me a couple of weeks, so I gave up
such tips, and i just file the copper ones every day. They are cheap.
There is nothing under aud $150 for "soldering stations", with Goot at $270.
These look fragile for heavy soldering, and repetitive continuous use,
left on for 8 hrs a day, 300 days a year.
Even the power cables of mine go open after 6mths, due to the fatigue
on the wires at the handle entry, so I have had to tape
them up heavily.
El cheapo chinese irons are from $15 /25w to $23 / 80w.
Instead of buying an expensive iron, I can afford to throw away
7 chinese irons over 7 years; I bet the low voltage irons
won't last that long with the use I give them.
An iron is an iron, and the 40w ones I use for tag strip soldering
work fine. With a short tip, they work OK on nearly all the heavy tube gear.
> The good stuff all runs the heaters off
> of 28V, and is temperature controlled. A good thin multicore rosin
> 60/40 solder is a must: Kester, Ersin,... Stay away from anything that
> boasts that it is ecological. Wash your hands after work, every time.
>
> >
> > Premade kits teach you to solder someone else's thoughts together,
> > and saves you using your brain to make the decisions along the way,
> > so you learn nothing.
>
> On this I disagree! The act of designing a circuit coming up with the
> proper parts, and machining a chassis, and assembling is way too big a
> step for anyone to take. This advice is the right advice to give to
> someone that you DON'T want to learn about electronics.
I learnt that kits taught me nothing about electronics.
I agree to disagree Chuck, and let ppl decide for themselves
>
>
> A good kit will have a tested circuit, all the parts needed, a punched
> chassis, and a simple plan that shows how to wire the circuit.
>
> It is quite enough to go through this process and make your first
> working amp.
A line stage preamp should present litle problem to the novice
with INTELLIGENCE, who will persue the designing with great
attention to detail, to the nth degree, and turn out something better
than many kits.
They won't just make a mess, they will see the errors of their ways,
and their preconceptions of what they want to end up with will
become a reality. They will be able to conceive a plan, draw up a
set of plans accurately, consult with others on what's best if necessary,
and proceed cautiously.
They will make the time available. This is the attitude of the craftsperson,
artisan, artist.
When you are done, you will have a model that you can
> listen to, measure and contemplate. If your curiosity allows, you can
> try simple changes to see what happens. Since you built the kit, you
> can always put it back to the way it was. Kits that are hand wired
> are best (eg. no circuit boards!)
Mny kits come with printed circuit boards, and allow little experimentation.
>
>
> >>I'd love to put together an FM tuner but I doub't any such kits using
> >>bottles are out there and
> >>if so they would most probably be too advanced.
>
> Once upon a time, there was a company called Heathkit. They made a very
> nice, simple tube FM tuner Kit. It worked very nicely, and was simple
> to get going with very little test gear. But alas they are no more!
>
> A friend gave me one (FM1, I think it was), I deemed it useless, and
> tore it apart... Then I rebuilt it from the instructions and used it
> for several years... Became a big bad engineer and learned that tubes
> were bad, solid state was good.... So I took it apart once more. I wish
> I could remember where the parts are, 'cause I'd like to build it again.
>
> > I post enough info to allow diyers to do their own.
> > A few have managed it, even winding their own OPT's to my recipe.
> > But this takes enormous dedication.
> > But I know guys who build aeroplanes and yachts in their backyard.
> > One did a big yacht, and had to demolish part of the house, to get it to the water.
> > Then he sailed around the world for years.
>
> It's asking rather alot of a newbie to build from your designs, Patrick.
> You don't go into the details of some of the simple but important parts,
> like power supplies. It is kind of like expecting a baby to do brain
> surgery.
I went ahead with little knowledge, but then I was rather keen.
I am use to problem solving and analytical thought, and being
skeptical about what I build along the way, to make sure I have not
missed anything, and that I guessed nothing, and understand everything.
I had got used to this process from
20 previous years designing extensions to houses, and then buiding them,
often while the owners watched over the shoulder.
I don't expect a baby to learn brain surgery at 6mths.
ppl should never attempt anyrthing they fell uncomfortable with.
I just couldn't find off the shelf trannies at a price I wanted to pay
when I got keen to learn in 1993.
I didn't feel uncomfortable, I just felt pissed off I couldn't get any trannies cheaply.
There were not even any Hammonds imported then.
So I built a winding lathe and tried chokes, then mains trannies, then OPTs,
and after doing a dozen, I got cooler temperatures than any
commercial designs for the mains trannies, and better F response and lower losses
than any amps I tested.
There are so very few ppl who wind their own transformers.
I felt really at ease once I got going; the key component performance
was under my creative control.
So I am not dependant on the outside world for key components.
I make most of my chassis, after the place I used to get them cheap went broke.
So if someone is keen, they damn well do it!
The not so keen just buy the trannies off EVATCO here, who import
mains T, chokes, and OPTs.
For a pair of mono 50W amps, ppl will pay around aud $800 for a passable
set of iron for the amps. I pay $200 in material costs, and
work a couple of weeks to get better performance.
You have covered a few things I didn't mention, so if anyone puts your
list together with mine, they get a nice list.
>
>
> As to kits, I thought Patrick could be of help, but I guess he doesn't
> go that way.
Its no use me doing kits, because the kit market is so riddled with
kits which are purchased on the basis of price, and little else.
Unless I could get all my parts made in china, I'd go broke making kits.
>
>
> If you want to roll your own, Antique Electronics Supply has designs,
> parts, and everything you need all in one place. The term "breadboard"
> comes from the old habit of swiping the wife's wooden cutting board and
> building radios, etc. using brass wood screws as terminals, and screws
> and bushings to hold up sockets, ... It is a tried and true method, and
> works... Very low cost too. Googling "Amplifier kits tube" will show
> up a long list of companies that are providing kits. You should be
> able to get by for under $400 for something really nice. SET's are easy
> to build, but not enough easier to rule out a PP 6L6.
>
> Anyway, you have a bit of thinking to do before you start.
That I agree with.
There is a heck of a lot more thinking to do before
you finish.
> Merry Christmas Ayn,
And Merry Christmas Chuck.
Patrick Turner.
Henry A. Pasternack
news:20031222082802...@mb-m07.aol.com...
> Any multimeter will suffice. The accuracy of the readings does not affect
the
> sound :)
Sometimes I think, Al, that you are saying there is absolutely no
relationship
whatsoever between theory and measurements and subjective sound quality. I
believe there is a significant body of evidence proving that's not the case.
-Henry
Patrick Turner
"Henry A. Pasternack" wrote:
Al is the Mystical Audiologist.
He does not worry too much about what meters tell him
if the sound is already just beautiful.
Some folks might weep for days if the thd measured above 0.001%,
but neither Al or myself would.
I think he is being humerously facetious.
Patrick Turner.
TubeGarden
It may be possible a middle path exists between no relationship and requiring a
big buck meter.
My Rat Shack special tells me enough to have led me very close to the Aural
Truth :)
At least, occasionally, maybe ;)
It may not be prudent to tell a beginner that only a Fluke will set them free
:)
Sing the song, bang the gong :)
Patrick Turner
TubeGarden wrote:
> Hi RATs!
>
> It may be possible a middle path exists between no relationship and requiring a
> big buck meter.
>
> My Rat Shack special tells me enough to have led me very close to the Aural
> Truth :)
It was a revelation to use a digital meter after so many years struggling to
read an anlaog meter which wasn't dead accurate anyway.
Even the cheap meters are within 1%.
>
>
> At least, occasionally, maybe ;)
>
> It may not be prudent to tell a beginner that only a Fluke will set them free
> :)
Well its only a Fluke that I don't see more smoke around the workshop.
I could not Resist going digital, and my Capacity for understanding
was greatly Induced.
And electrons have Impudence, do they not?
Patrick Turner.
Chuck Harris
Maryland how to build and test electronic circuits, we didn't
give them a meter at all! They had a cheap 5000 series Tektronix
scope (500KHz bandwidth). The scope could read out to 3% or so, and
that was more than good enough. The scope was their voltmeter,
CRO, and frequency meter all in one.
Seriously, if your tube circuit needs 0.01% measurement accuracy to
work correctly, you designed it wrong. 3% is easily good enough.
What you do need in a voltage measurement device, is safety, and low
burden. By that I mean, measuring 1KV shouldn't put the operator
at undue risk, and the meter shouldn't excessively load the circuit
under test.
-Chuck
Patrick Turner
Chuck Harris wrote:
> Back when I was teaching the Kiddies at the University of
> Maryland how to build and test electronic circuits, we didn't
> give them a meter at all! They had a cheap 5000 series Tektronix
> scope (500KHz bandwidth). The scope could read out to 3% or so, and
> that was more than good enough. The scope was their voltmeter,
> CRO, and frequency meter all in one.
>
> Seriously, if your tube circuit needs 0.01% measurement accuracy to
> work correctly, you designed it wrong.
I think that applies to all circuits, except special scientific apps
> 3% is easily good enough.
If you measured 0.103% or 0.097% thd, its good enough.
>
>
> What you do need in a voltage measurement device, is safety, and low
> burden. By that I mean, measuring 1KV shouldn't put the operator
> at undue risk, and the meter shouldn't excessively load the circuit
> under test.
True, and a digital auto ranging Fluke is a breeze to use.
The accuracy is a bonus.
There are all these figures after the decimal point, and one don't have to use them
all
in many calculations. But one has to be on the lookout where small things have to be
noted carefully.
A CRO is the hard way to measure voltage, but a valid way, if you
try to get a quick measure.
I use a logarithmic amp to power my 4" wide analog meter to record
voltage measurements from a microphone.
This means 0dB is in the centre of the meter, and +30 dB is to the left,
and -30 db to the right, and there are 3 dB steps along the way across the
60 dB range for the meter, and this saves mucking around
re-referencing when one drops below -20 dB on a normal meter.
It was easy to calibrate using resistance divided voltages.
0.1-0.3, 0.3-1, 1-3, 3-10, 10 to 300, 300 to 1000 makes more sense
when reading a range of voltages on an analog meter, so that
when a voltage of 0.12v has to be read, one isn't reading
it down at the low end of a 0.0-1 scale, but on the 0.1-0.3 scale.
If the meter isn't zeroed properly, you get errors down the low end.
My Fluke is good at AV, but only up to 1 kHz,
and so I built my own multi-range AVM, which reads vrms and dB
with a large 4" analog meter, and solid state amp and rectifier,
500k Rin, and 2Hz to 2 MHz of BW, with over voltage limiting.
It is still tedius to measure the voltage level response
of an RIAA filter accurately enough to verify that its within +/-1dB accurate
In this case, I use a reverse RIAA filter to eq a flat responsed input signal,
ie, eq the signal like a record cutter signal, and then apply that to
the amp I am measuring, and adjust the R&C for a flat response, and a
"good" square wave.
Patrick Turner.
Chuck Harris
like:
"The girls all dressed-up to please each other..."
I think test equipment is alot like that. We have reached a
point where the test equipment is so accurate that the only
people who need the accuracy are those that build test equipment.
I use a DVM for much of my work. I like the simplicity of reading
the measurement. But I don't necessarily recommend a DVM for a newbie.
The reason I don't is it tends to make you think that accuracy of that
level actually matters... It doesn't 99% of the time. When you use a
DVM, and make a reading of 15.025V, do you write down 15V, or do you
write down 15.025V? I would say that most will write down 15.025V.
Similarily, if the DVM says 153.5V do you write down 154V? 150V?
153.5V?
Estimation is easy with a CRO. Leave the CRO set in one of the "5"
settings (eg. .5, 5, 50 V/div) and read the small divisions directly
as 0.1, 1, or 10 volts.
With an analog meter, it is much the samething, you mostly use the
scales that have divisions that easily go to volts, and avoid the
ones that have strange small divisions that require counting on your
fingers.
There are cases where 0.01% is helpful, but usually the need for that
kind of accuracy and precision is born of making the measurement the
wrong way.
For instance, if you are using a DVM's ohmmeter to adjust the resistance
of a high current shunt, a reading of 0.01 ohms, vs 0.02 ohms can make
a really big difference. But you shouldn't be using the DVM that way,
you should be running a lot more current through the shunt, and
measuring a larger voltage drop.
-Chuck Harris
Sander deWaal
>.......................
>Weller mains irons at aud $60, (us $42) are made here by Cooper Tools,
>with a plant in Albury-Wodonga. I sent back the ones that failed, and they sent me
>2 replacements they said would not fail but of course they did, within 15 mths.
>I asked them for a 12v version of the same iron, so that the heating wires would be
>thicker, and less prone to going open, and they said the cost of a transformer is
>prohibitive in the Aust market, where folks buy the $20 chinese throwaway iron, like I do
>now.
>...........................
Can't you use an autotransformer from 245 >220 (or 230), or a variac??
I mean, I've got 2 Weller stations in use, one of which (WTCP) is
about 15 years old and this one has had a "bad youth" so to speak.
At some time, it's been on for almost 6 years 24/7 continuously, no
problems except changing tips.
The other one is a WECP which is about 8 years old, and never failed
me too. It's in use almost every day as well.
All of this despite the fact that we went slowly from 220 to 230 volts
over the past years.
Sander deWaal
>I use a DVM for much of my work. I like the simplicity of reading
>the measurement. But I don't necessarily recommend a DVM for a newbie.
>The reason I don't is it tends to make you think that accuracy of that
>level actually matters... It doesn't 99% of the time. When you use a
>DVM, and make a reading of 15.025V, do you write down 15V, or do you
>write down 15.025V? I would say that most will write down 15.025V.
>Similarily, if the DVM says 153.5V do you write down 154V? 150V?
>153.5V?
Well, one reason for recommending a DVM is that they're dirt cheap,
and usually have a high input resistance of 1 Mohm or higher.
The "accuracy" of said cheap meters is of course discutable,
especially over a longer period of time.
But I'll take a cheap DVM over a cheap analog meter every day,
especially in tube circuits with their usually high rsistance values.
Another possibility, which I use, is to create an output/input loop on
the scope's Y-amp, in order to use the calibrated attenuator and the
fixed 1 Mohm/9 pF of the scope to drive an analog dB and mV meter.
There's also the possibility to put a selective filter inbetween to
measure THD and simultaneously see on the scope what's happening.
These little modifications to my scope were some of the best things
I've ever done, it makes fast analysis possible without wiring up a
stack of gear every time.
Next to that, I use a simple analog I/O soundcard on an obsolete
486/100 with a little program to measure HD, IMD, do some waveform
analysis and create printouts of the DUT's performance. Recommended!
Chuck Harris
> Can't you use an autotransformer from 245 >220 (or 230), or a variac??
> I mean, I've got 2 Weller stations in use, one of which (WTCP) is
> about 15 years old and this one has had a "bad youth" so to speak.
> At some time, it's been on for almost 6 years 24/7 continuously, no
> problems except changing tips.
> The other one is a WECP which is about 8 years old, and never failed
> me too. It's in use almost every day as well.
> All of this despite the fact that we went slowly from 220 to 230 volts
> over the past years.
>
That is my experience as well. I have A WTCPN that is more than 20
years old, and has been on most of that time. The tips last a gawd
awful long time. I used to hate the copper tips with a vengeance. The
Iron plated tips are vastly superior.
I also have an Ungar 9900, and it has getting to be 10 years old.
Ungar was bought by Weller/ Cooper Tools, and the Ungar 9900 was
rereleased under the Weller name.
The reason that the Soldering stations last so long is they don't use
nichrome heating elements. They use an amorphous ceramic power
resistor as the heating element. No part of the hot stuff is exposed
to the air, so it doesn't break down. 700F is nothing to a power
resistor.
Don't get me wrong, I can solder with anything from a torch to a
soldering gun. But after having tasted the sweetness of a temperature
controlled soldering station I never want to go back to the old
ways.
-Chuck Harris
Patrick Turner
Sander deWaal wrote:
I have a resistor box under the bench, just to cut down the heat a bit,
with a two pos switch.
That didn't lengthen the life of the irons I bought.
The guy at the factory said I may have got one from a crook batch,
and that the water from the Murray River was too salty to use in the ceramic process.
So why not distilled water? I said.
I must have blown 5 irons the last 8 years, and so I go chinese.
Patrick Turner.
kyser
> I have a resistor box under the bench, just to cut down the heat a bit,
with a two pos switch.
>
> That didn't lengthen the life of the irons I bought.
> I must have blown 5 irons the last 8 years, and so I go chinese.
>
> Patrick Turner.
You'd be FAR better off with one of these .....
Patrick Turner
kyser wrote:
Maybe, I am a bit tight arsed, and when the weller/chinese irons work,
they do it all very well.
When my chinese iron blows, I could be tempted.
Patrick Turner.
Greg Pierce
enlightened us with these pearls of wisdom:
I still have a WTCPT iron. The power supply died years ago, so I replaced
it with a Tamura 24V 4A transformer that I got for $5 when our local Radio
Shake.com was closing it's doors. Works fine. I use it for any heavy stuff.
For most chores, I have a Weller WES50, which is their standard, low-buck
dial adjustable soldering station. What I would like to have is a Metcal
station, or possibly one of the Weller WSL stations with the WMP pencil
iron. I wonder if the Weller's price is as steep as the Metcal...
--
Greg
--The software said it requires Win2000 or better, so I installed Linux.
BFoelsch
February 28(?), buy a WSL station and get a free WSP80 iron.
The WSL is not cheap, I paid 210 USD, but with the offer of the free WSP80
it isn't too bad.
WSL is great, heats up in (literally) 10 seconds. I love having the tip just
a few inches away from my fingers, kind of feels like an old fountain pen.
Just 2 things. First, the standard tip is a .010" conical point, which is
really, really fine. Plan on getting a few more tips unless you do SMT
exclusively. Second, I haven't perfected the technique for tightening the
tips yet. Seems like they loosen spontaneously, but I am sure that
tightening them in the proper state (hot, warm, cold) will rectify that.
On the main thread, I have been using the W60 and WTCP for at least 25 years
with no repairs except the tips and tip nuts. About the most robust
temperature sensing mechanism I have ever seen.
As an earlier poster said, once you use a temperature controlled iron with
an iron-clad tip you can't go back. It can sit for hours without burning the
tip or overheating. I just regret all the time I have wasted with soldering
guns.
"Greg Pierce" <tras...@nospam.com> wrote in message
news:pan.2003.12.24....@nospam.com...
kyser
Well, I've had Scopes (years ago); Arlecs (good, but now defunct); a Weller
(crap!!!); the cheap Chinese ones etc etc, and believe me, while I jibed a
bit at the price of the Duratech station, I bought one a bit over a year
ago, and it's _easily_ the best soldering iron I've ever owned.
It heats in seconds, holds a constant temperature, can be cranked up to 480
degrees C for heavier work, the tips are available in several sizes, and are
easily changed .... It's great!
Dick Smith sell something similar for $128, and occasionally less on
special.
http://www.dse.com.au/cgi-bin/dse.storefront/3fe925cc004de97e273fc0a87f9c0716/Product/View/T2200
And no, I have no interests whatsoever in Jaycar (or DSE, for that matter) -
I just hate crap soldering irons ...... 8^)
Patrick Turner
kyser wrote:
A good tradesman never blames his tools.
I can do nice need work with a chinese iron.
But when it conks out, i might try a Duratech.
Patrick Turner.
Phil Allison
"Patrick Turner" <in...@turneraudio.com.au>
> A good tradesman never blames his tools.
** And real tradesmen never uses poor quality tools.
So the Turneroid is caught with egg on his face again.
> I can do nice need work with a chinese iron.
** The Turneroid builds amps in a wok.
.......... Phil
Greg Pierce
enlightened us with these pearls of wisdom:
> Just purchased a WSL. FWIW, Weller is running a special from now until
> February 28(?), buy a WSL station and get a free WSP80 iron.
>
> The WSL is not cheap, I paid 210 USD, but with the offer of the free WSP80
> it isn't too bad.
Actually, that IS cheap. A Metcal station starts at about $300 for an
SP-200 station (roughly equivalent to the WSL), while the MX-500
starts at around $650 (dual port HF power supply and one handle).
Neither one includes tips, which are $15-$30 each, depending on
the type and temperature. If you want a rework station (MX-500 PS,
one handle, and one desoldering handle) you will spend $900 or so.
They are expensive, but after you use one you really start to
appreciate it. It gets hot in a few seconds, stays hot even when
you start really loading it up, and turns itself off automatically if
it senses no use for 30 minutes. Here's the URL:
http://www.metcal.com/products/1.2.1.htm