Building my own valve amp
 

"Trevor Wilson" wrote


snip magazine reviews and personal OSAFs


When examining the frequency response plots of the SET amps we can see
serious, highly audible flaws. When examining the distortion plots, we
can see serious audible flaws in most models at realistic listening
powers. Examining the plots of the other amplifiers, we can see no
obviously audible flaws. Choosing a SET amp over a push pull amp, is
therefore the deliberate choice of audible problems. Those audible
problems are completely artificial artefacts, not present in the
original sources.


Your problems are not everybody's problems - choice of a SET is to
choose an amp for its characteristics. The bit you can't choke down is
that people buying/choosing/using SET amps consider those
characteristics to be beneficial. Three members of the 'St Neots Six'
(local enthusiasts) own and use SETS, one of the others prefers my SET
to my PP amps, another would like a SET and the last one keeps
threatening to build one but probably never will as he is getting
perhaps a bit to old for more building - otherwise that could easily
become a *100%* instance of SETs here!!



The choice of such an amplifier is, therefore, a rejection of the
musician's/producer's philosophy.


Which is what?


The SET owner may be better off using a
'blameless' amplifier, with some tone controls and a little additional
distortion and noise.


Or he could just use a SET and be done with all that crap....



Whilst not stated in the graphs, we also need to understand what
constitutes a *proper* amplifier. A proper amplifier is the *ideal*
source. IOW: It neither adds, nor subtracts anything to the music.
Fundamentally, a SET fails this simple test very early on. Most
amplifiers are rated for XX Watts @ 8 Ohms. Fine, as far as it goes,
but the ideal amplifier will be rated for XX Volts output. IOW: It
will maintain XX Volts, regardless of load impedance. Or, to put it
another way: An ideal amplifier, rated for 100 Watts @ 8 Ohms, will
deliver 200 Watts @ 4 Ohms, 400 Watts @ 2 Ohms and so on. Naturally,
in the real world, this is an impossibility. However, some amplifiers
do come pretty close, provided saturation effects are taken into
account. For example, if we examine a typical, quality, push pull
amplifier, rated at 100 Watts @ 8 Ohms. The same amplifier might,
typically, deliver 150 Watts @ 4 Ohms and 175 Watts @ 2 Ohms. This
allows for a choice of speakers and, as the vast majority of
loudspeakers do not exhibit a perfectly resistive impedance
characteristic, is a darned good idea.


Funnily enough, all that came out when Chinese Willy was here the other
day - another instance of where fine theory falls on its arse in the
real world...



A SET amplifier, OTOH, might be rated for (say) 10 Watts @ 8 Ohms.
It's 4 Ohm power, therefore, be less than 5 Watts. It's 2 Ohm power
will be less than 2.5 Watts. It is the complete and almost perfect
antithesis of a theoretically ideal amplifier. An ok choice, IF you
happen to be using a perfectly resistive load. For anything else
(particularly ESLs), it is the worst possible choice.

SETs are a fashion statement. They're not serious high fidelity
products. Their promoters are, at best, deluded. At worst, cynical
opportunists.


Who TF's promoting them? - I only defend my preference for them. If you
or anybody else don't like and doesn't want a SET amp then fine, don't
have one...

Building my own valve amp
 

"Andy Evans" wrote in message
oups.com...
"we can see audible flaws" v. "we can see no obviously audible
flaws." (Trevor)

This is really the problem with your thinking here. You can't "see"
sound in its entirity. You can "see" a representation which, like all
representations, is merely acting in place of the original. I can see
quite clearly that your desire to refer your arguments to such
representations is seductive to your own ways of analysis, but it's
clear from our panel of "SET idiots" here that it doesn't satisfy the
musical brains of discriminating listeners who need to actually hear
those minute musical differences which, for instance, discriminate
between a Stradivarius and a practice violin.


There is no big mystery AFAIAC - valves give more clarity, 'air' and
*life* than any SS I've heard; SETs add more depth and better imaging
than PP, making the sound more *natural*....

Is that too simple??

Building my own valve amp
 

"Andy Evans" wrote in message
ups.com...
What's interesting about Trevor is that he is simultaneously saying
that you can "see" the sound of an amp from representations of it, but
on no account should you trust anything but your ears because you HAVE
to hear before making your choice.

Then he turns around to people who have done exactly that - chosen
SETs with their ears - and says that they should have made their
judgement on the basis of visual response plots.

Hmmmm. Is this a case of "he who has the most internal contradictions
shouts loudest for rational thought?"



Perhaps he should change his dictum from 'hear before you buy' to 'hear
before you buy, but be careful not to get it wrong'...??

:-)

Building my own valve amp
 

"Andy Evans" wrote in message
oups.com...
"we can see audible flaws" v. "we can see no obviously audible
flaws." (Trevor)

This is really the problem with your thinking here. You can't "see"
sound in its entirity.

**Correct. What you can 'see', however, are obvious audible problems. Any
amplifier with clear and obvious problems can be discounted as a non-high
fidelity product.

You can "see" a representation which, like all
representations, is merely acting in place of the original. I can see
quite clearly that your desire to refer your arguments to such
representations is seductive to your own ways of analysis, but it's
clear from our panel of "SET idiots" here that it doesn't satisfy the
musical brains of discriminating listeners who need to actually hear
those minute musical differences which, for instance, discriminate
between a Stradivarius and a practice violin.

**Non-sequitur. You fall for the trap, by assuming a REPRODUCTION system has
any relation to a CREATION system. The two may be very different. In fact a
SET amp may well be a valid part of a sound CREATION system.

[ANECDOTE] Many years ago, I used to service equipment for musicians. One
guy presented me with this piddling practice amp. 10 Watts. All valved
(including rectifier). He was the lead guitarist for a rock 'n roll band. A
pretty good one, as it happens. I asked the obvious questions about why he
needed so urgently (Friday night), after all, it was only a practice amp. He
gently informed me that it was his stage amp. He loved the sound of the amp,
so he mic'd it through (ironically) a very large SS PA system.


The choice of such an amplifier is, therefore, a rejection of the
musician's/producer's philosophy.

A musician isn't a producer.

**A musician may well be a producer. Or not.

A musician has ears, not philosophies of
sound.

**Not necessarily.

A musician would no more buy a Stradivarius because of its
frequency response plots than he would.........

**How do you know that? Here in Australia, we have a violin manufacturer who
has been trying to emulate the sound of a Strad for many years. He uses
quite a bit of test equipment to do so. Test equipment does not rule out the
use of human ears. However, test equipment allows the engineer sort out the
obvious problems from the get-go.

(here comes to mind the immortal words of my harmony tutor at the
Royal Academy of Music in London "Andy, Beethoven would no more have
written that chord than he would have ****ed his own mother...)

Do musicians flock to concert halls to look at scores of the Rite of
Spring? Of course not - they listen to sound like we all do. Why are
you so hung up about representations? The rest of us listen to the
stuff we build and judge with our ears.

**Here's a thought: Do some measurements and dump the stuff which has clear
and obvious problems.


You're going to tell us now that our ears are inadequate to hear sound

**Non-sequitur.

- I can just see you creeping round the corner as I write.

**I doubt that.

Trevor Wilson

Building my own valve amp
 

"Nick Gorham" wrote in message
...
Trevor Wilson wrote:

Here is another, quite decent amplifier (US$899.00):

http://stereophile.com/integratedamp...ad/index5.html


Ahh, so what you are suggesting, is that anyone who decides to spend more
than £450 on a solid state amplifier is a "idiot" (never saw your
definition BTW). I could live with that as a logical argument.

**Non-sequitur. Feel free to demonstrate how you reached that little leap of
logic. I could use a laugh today.


So, what is it that you make again?

**Fools of people who think they know better.

Trevor Wilson

Building my own valve amp
 

"Andy Evans" wrote in message
ups.com...
What's interesting about Trevor is that he is simultaneously saying
that you can "see" the sound of an amp from representations of it, but
on no account should you trust anything but your ears because you HAVE
to hear before making your choice.

**Nope. As usual, your inability to deduce a logical conclusion from obvious
statements is duly noted. I am simply stating that any amplifier which has
clear and obvious flaws may be removed from any selection process.


Then he turns around to people who have done exactly that - chosen
SETs with their ears - and says that they should have made their
judgement on the basis of visual response plots.

Hmmmm. Is this a case of "he who has the most internal contradictions
shouts loudest for rational thought?"

**Your inability to comprehend straightforward logic is duly noted.

Trevor Wilson

Building my own valve amp
 

"Keith G" wrote in message
...

"Trevor Wilson" wrote


snip magazine reviews and personal OSAFs


When examining the frequency response plots of the SET amps we can see
serious, highly audible flaws. When examining the distortion plots, we
can see serious audible flaws in most models at realistic listening
powers. Examining the plots of the other amplifiers, we can see no
obviously audible flaws. Choosing a SET amp over a push pull amp, is
therefore the deliberate choice of audible problems. Those audible
problems are completely artificial artefacts, not present in the original
sources.


Your problems are not everybody's problems - choice of a SET is to choose
an amp for its characteristics. The bit you can't choke down is that
people buying/choosing/using SET amps consider those characteristics to be
beneficial.

**Which characteristics? Which SET amp? They're all different. Is it the
crap frequency repsonse? The high levels of distortion? Or the poor load
tolerance?

Three members of the 'St Neots Six'
(local enthusiasts) own and use SETS, one of the others prefers my SET to
my PP amps, another would like a SET and the last one keeps threatening to
build one but probably never will as he is getting perhaps a bit to old
for more building - otherwise that could easily become a *100%* instance
of SETs here!!



The choice of such an amplifier is, therefore, a rejection of the
musician's/producer's philosophy.


Which is what?

**That would depend on the musician/producer.



The SET owner may be better off using a
'blameless' amplifier, with some tone controls and a little additional
distortion and noise.


Or he could just use a SET and be done with all that crap....

**That is one, inconvenient and expensive option. It is easier and cheaper
to just cripple a push pull amp.




Whilst not stated in the graphs, we also need to understand what
constitutes a *proper* amplifier. A proper amplifier is the *ideal*
source. IOW: It neither adds, nor subtracts anything to the music.
Fundamentally, a SET fails this simple test very early on. Most
amplifiers are rated for XX Watts @ 8 Ohms. Fine, as far as it goes, but
the ideal amplifier will be rated for XX Volts output. IOW: It will
maintain XX Volts, regardless of load impedance. Or, to put it another
way: An ideal amplifier, rated for 100 Watts @ 8 Ohms, will deliver 200
Watts @ 4 Ohms, 400 Watts @ 2 Ohms and so on. Naturally, in the real
world, this is an impossibility. However, some amplifiers do come pretty
close, provided saturation effects are taken into account. For example,
if we examine a typical, quality, push pull amplifier, rated at 100 Watts
@ 8 Ohms. The same amplifier might, typically, deliver 150 Watts @ 4 Ohms
and 175 Watts @ 2 Ohms. This allows for a choice of speakers and, as the
vast majority of loudspeakers do not exhibit a perfectly resistive
impedance characteristic, is a darned good idea.


Funnily enough, all that came out when Chinese Willy was here the other
day - another instance of where fine theory falls on its arse in the real
world...



A SET amplifier, OTOH, might be rated for (say) 10 Watts @ 8 Ohms. It's 4
Ohm power, therefore, be less than 5 Watts. It's 2 Ohm power will be less
than 2.5 Watts. It is the complete and almost perfect antithesis of a
theoretically ideal amplifier. An ok choice, IF you happen to be using a
perfectly resistive load. For anything else (particularly ESLs), it is
the worst possible choice.

SETs are a fashion statement. They're not serious high fidelity products.
Their promoters are, at best, deluded. At worst, cynical opportunists.


Who TF's promoting them?

**Those who know no better. Or those who ae charlatans.

- I only defend my preference for them. If you
or anybody else don't like and doesn't want a SET amp then fine, don't
have one...

**Indeed. I don't see your problem. I simply point out the obvious problems
and the logical inconsistencies of those who use them.

Trevor Wilson

Building my own valve amp
 

"Keith G" wrote in message
...

"Andy Evans" wrote in message
oups.com...
"we can see audible flaws" v. "we can see no obviously audible
flaws." (Trevor)

This is really the problem with your thinking here. You can't "see"
sound in its entirity. You can "see" a representation which, like all
representations, is merely acting in place of the original. I can see
quite clearly that your desire to refer your arguments to such
representations is seductive to your own ways of analysis, but it's
clear from our panel of "SET idiots" here that it doesn't satisfy the
musical brains of discriminating listeners who need to actually hear
those minute musical differences which, for instance, discriminate
between a Stradivarius and a practice violin.


There is no big mystery AFAIAC - valves give more clarity, 'air' and
*life* than any SS I've heard; SETs add more depth and better imaging than
PP, making the sound more *natural*....

Is that too simple??

Gosh Keith. You statement that "SETs add more depth and better imaging"
is incredibly deja-vu. It was a comment also made by another poster on
another NG a while ago, in another thread, which you probably have
not seen. Trevor took exception to this immediately, despite the fact
that it is an important and fundamental reason why people choose SET.

Iain

Building my own valve amp
 

"Andy Evans" wrote in message
oups.com...
"we can see audible flaws" v. "we can see no obviously audible
flaws." (Trevor)

This is really the problem with your thinking here. You can't "see"
sound in its entirity. You can "see" a representation which, like all
representations, is merely acting in place of the original. I can see
quite clearly that your desire to refer your arguments to such
representations is seductive to your own ways of analysis, but it's
clear from our panel of "SET idiots" here that it doesn't satisfy the
musical brains of discriminating listeners who need to actually hear
those minute musical differences which, for instance, discriminate
between a Stradivarius and a practice violin.

The choice of such an amplifier is, therefore, a rejection of the
musician's/producer's philosophy.

A musician isn't a producer. A musician has ears, not philosophies of
sound. A musician would no more buy a Stradivarius because of its
frequency response plots than he would.........
(here comes to mind the immortal words of my harmony tutor at the
Royal Academy of Music in London "Andy, Beethoven would no more have
written that chord than he would have ****ed his own mother...)

Do musicians flock to concert halls to look at scores of the Rite of
Spring? Of course not - they listen to sound like we all do. Why are
you so hung up about representations? The rest of us listen to the
stuff we build and judge with our ears.

You're going to tell us now that our ears are inadequate to hear sound
- I can just see you creeping round the corner as I write.


Andy. On the subject of SET, TWis conveniently forgetting the fact that
good SETs run at very low power, and are used with sensitive loudspeakers.
Such a system can fill a good sized room with magnificent music at 1W.
At such a low power, the THD is usually 0.1%

Iain

Building my own valve amp
 

"Nick Gorham" wrote in message
...

As Jim said, no one can make any more specific suggestions until we know
more details, but all the OP wanted was info about building his own, and
forums that would be relivant to that.


The OP posted, (but did not cross-post) the same question to other NGs.
He got helpful responses with a list of good projects, and also some
required reading.

Hopefully, he has made a start already:-)

Iain