Valve amp (preferably DIY) to drive apair of Wharfedale Diamond II's
 

In article ,
Ian Molton wrote:
Technology moves on.
In 50 years we have gone from state-of-the-art valve amps
that sound like "a straight wire with gain"
and don't have any "valve sound"
to today's abominations that are deliberately non-linear.

Truer words have not been spoken.

Yup. And I wonder why all these valve nuts seem to ignore the decent valve
amps like the Radford STA 25, or Quad II, and prat around with cheap
Chinese junk. If there had been any advance in valve design or circuitry
in these last 40 years or so, it might be a reason. But there hasn't.

--
*Keep honking...I'm reloading.

Dave Plowman London SW
To e-mail, change noise into sound.

Valve amp (preferably DIY) to drive apair of Wharfedale DiamondII's
 

Jim Lesurf wrote:
In article , Rob
wrote:

Ian Molton wrote:


Ok, in that case, explain to me why you cant seem to even accept the
possibility that (good) SS amps sound 'cold and harsh' due to an
absence of audible distortion.



IMO entire human perception is shrouded in distortion and I find this
whole debate about 'causal distortion' a red herring. Certainly, by
measurement using certain 'rulers', a valve amplifier will provide a set
of measurements different to that of a SS amplifier.


I would agree that it does seem to be the case that human physiology means
that our hearing system is quite non-linear, and hence does not always
react as we might think. However I don't think it follows from this that
distortion in audio equipment is a 'red herring'. It can alter the results
in an audible way, and hence must matter if we have an interest in the
results.

Well, I think the red herring is the association. Many of the technical
contributors near enough instantly associate 'the distortion of valve
amps' with 'imperfect sound amplification'. That for me is just not good
enough. Think of the amp as a lens - a valve amp 'bends the light' in a
way that allows focus. Some wouldsay distortion, I'd say focus, and it's
the curious sense of space that valve amps relay plus the 'smoothness'.


And anyway, isn't distortion from a valve amp (say 25w) negligible at
decent sound levels (say 5w)?


It is my intuitive feeling that many SS amps distort source sound in a
way less benign than that of many valve amps.


But it may be that your "intuative feeling" is simply incorrect as a
description of reality once you use the term "distort" which has a quite
specific definition in the context of measurements on audio equipment. Thus
it may be that your statement is unreliable.

Of course! But please bear in mind:


I have learned this by listening, not measuring.


Again, by "learned" here you presumably mean "I have formed this feeling as
it seems consistent with hearing a difference and preferring one sort of
amp".

However would it not also be quite consistent with your experience to say
that you prefer the sound altered in a given way by a valve amp, so simply
miss this when listening to a SS amp? - i.e. it does not tell you anything
about the presence or absence of distortion in a SS amp beyond saying it
does not share the distortion of a valve amp?

More or less, yes. It's just that I'm unhappy with the word 'altered'.
Valve amplification (or at least all that I've heard) just gets me
closer to the essence of what I believe music sounds like. You would say
altered - because the amplified signal deviates from the original
recorded pattern to a greater extent. The incredibly frustrating thing
for scientists is that my explanation has all the credibility of say a
homeopathy advocate. All I can say (again) is have a listen - I can't
explain it.

b/w

Rob

Valve amp (preferably DIY) to drive apair of Wharfedale DiamondII's
 

Keith G wrote:
"Rob" wrote in message
...

Ian Molton wrote:

Keith G wrote:


OK: I consider valve amps to generally sound clear, warm and fluid and
am perfectly happy to ascribe all of that to some form of distortion. I
consider, by comparison, ss amps to sound vague, cold and harsh and am
happy to ascribe all of that to some form of distortion.


cut

Hmm, I'm quite happy to qualify or explain any remark I have made in the
past or might make in the future,


Ok, in that case, explain to me why you cant seem to even accept the
possibility that (good) SS amps sound 'cold and harsh' due to an absence
of audible distortion.

(or will you continue to pretend that you ****-canned me (yeah, right))

I think you'll find that you have been (er) '**** caned' but your point is
interesting.



Jeez, it'll be a blow to his ego to realise that he has, in fact, been
binned. ;-)


IMO entire human perception is shrouded in distortion and I find this
whole debate about 'causal distortion' a red herring. Certainly, by
measurement using certain 'rulers', a valve amplifier will provide a set
of measurements different to that of a SS amplifier.

It is my intuitive feeling that many SS amps distort source sound in a way
less benign than that of many valve amps.

I have learned this by listening, not measuring. And really, when all's
said and done, I could listen to either quite happily. It's just that I
have the time and money to choose - and given the choice I prefer the way
a valve amplifier does its job.

All IMO - I wouldn't bother biting if I were the OP. All I can say is have
a listen!



Rob, that was beautifully put - which is probably something to do you
becoming 'Dr Rob' in a very short while, while** I remains a simple
****-pusher from the sticks wi' nobbut a handful of 40 year old O-levels to
bless meself wiv.... :-)


:-) - As I've said - there's an inverse correlation between bits of
paper and the ability to explain things clearly!

Rob

Valve amp (preferably DIY) to drive apair of Wharfedale Diamond II's
 

"Dave Plowman (News)" wrote in message
...
In article ,
Ian Molton wrote:
Technology moves on.
In 50 years we have gone from state-of-the-art valve amps
that sound like "a straight wire with gain"
and don't have any "valve sound"
to today's abominations that are deliberately non-linear.

Truer words have not been spoken.

Yup. And I wonder why all these valve nuts seem to ignore the decent valve
amps like the Radford STA 25, or Quad II, and prat around with cheap
Chinese junk. If there had been any advance in valve design or circuitry
in these last 40 years or so, it might be a reason. But there hasn't.

--
*Keep honking...I'm reloading.

Dave Plowman London SW
To e-mail, change noise into sound.


Audio Research for example have put a lot of design work into their hybrid
power amplifier designs, using the best of both world's so to speak. If you
study their schematics you'll find they've come a long way from the early
ubiquitous RC coupled power amp... and it shows.

Mike

Valve amp (preferably DIY) to drive apair of Wharfedale Diamond II's
 

"Dave Plowman (News)" wrote:

In article ,
Ian Molton wrote:
Technology moves on.
In 50 years we have gone from state-of-the-art valve amps
that sound like "a straight wire with gain"
and don't have any "valve sound"
to today's abominations that are deliberately non-linear.

Truer words have not been spoken.

Yup. And I wonder why all these valve nuts seem to ignore the decent valve
amps like the Radford STA 25, or Quad II, and prat around with cheap
Chinese junk. If there had been any advance in valve design or circuitry
in these last 40 years or so, it might be a reason. But there hasn't.

I serviced a pair of Quad II amps last year, and it was decided the existing
tubes
be retained since their emissions were virtually as new, since they were
purchased as NOS a few years back and had not seen much use.
This included all the tubes, rectifiers, KT66 and EF86.

I removed the existing very poor standard electro capacitors from the amps,
and installed modern supply caps of 47 uF and 100 uF for the plate supply,
with a 2H choke
to make a CLC filter for the anode supply.
Dual R&C caps were fitted to the cathodes of each KT66 output tube,
and this improved the balance of DC in each half of the OPT primaries.

All the old resistors and coupling caps were replaced with modern metal film
and poloypropylene types respectively.

Before the improvements, the IMD caused by the power supply interference
was equal to the thd of the tubes.
After the improvements, the PS IMD was difficult to measure at normal
listening levels of 2 watts.

But then i tried swapping positions of EF86 around, and then KT66, and found
that with both samples of amps I could reduce thd at 2 watts by at least 12 dB

to less than 0.03%, and methinks this would be somewhat inaudible,
since 2 watts into 8 ohms is 4vrms, and 0.03% = 1.2 mV.

So had the designers of 1955 had the components we have now, their amps would
have been a lot better
than are commonly made now.

The efforts of ARC is such that their amps produce astonishly low thd figures
at 2 watts.

The line stage in an SP8 preamp has two cascaded gain stages, a cathode
follower output,
and a shirtload of NFB, and the thd compares favourably to
much modern SS gear with supposedly inaudible distortion levels.
ARC and Conrad Johnson, perhaps Lumley, and others continue to make
exceptionally fine audio amps.

Many tube amps are now configured as " SE ", ie, single ended amps
using a lone transmitter tube or 300B or multiple small tubes parallel
connected as one large tube.

I just sold a pair of new SE 35 watt amps which I made with 4 x 6CA7
configured with cathode feedback OPT windings and global NFB to make a total
of about 16 dB, which is a lesser amount of NFB than compared to
1960, and even though its SE, the thd is no more than a normally low thd PP
amp,
simply because I have chosen the driver stage carefully enough so that the 2H
of the driver triodes cancels the 2H produced in the output tubes.

The thd is less than 0.1% at up to 10 watts
into any load between 4 and 12 ohms, which means that at 1 watt its down
around 0.03%,
even though it is an SE amp.

So when folks say that old valve amps are better made than current new
manufacture, you need gumboots to prevent the bull**** staining one's
trousers.

Quad II, Leak, and many other designs were terribly affected by bean counters
preventing the full implementation of what were fine ideas at the time.

The chinese are now making some valve amps which are at least as good as some
of the 1955 crap that mostly has by now found its way to the dumper bins.
There is much crap around now made, but there always was crap made!



I have built quite a few tube amps which produce text book technical
performance
of less then 0.1% thd at a full po of 50 watts using say a quad of KT88,
and the full power bandwidth, Ro, thd is better than anything from 1955 that I
have ever seen.

The D.T.N. Williamson and McIntosh designs of the late 1940s were able to
boast
extremely good performance, but **real** examples of Williamson amps were
rarely
built, because the OPTs were never up to the original spec and
we were lumbered with lowest common denominator thinking, and the turns and
iron
and iron quality were all reduced to what i would call "crummy grade".

Nearly all makers of tube amps try to make their amps linear as possible,
but quite a few SE amps made now boast they have no NFB loop used,
so its impossible they will ever attain really low thd, but when used with
horns or
sensitive speakers, the thd at listening levels is under 0.1%.
I have listened to several systems with SE triode amps and heard no tube
colour,
just the sound of the performance with an uncanny sense of it being real.

The other thing is that tube amps always produce their first few critical
watts in class A
and the thd is principally a mix of 2H and 3H, and in small quanties at the
low levels,
and the resulting IMD isn't too bad, and probably similar to what is produced
in musical instruments.

But an SS amp needs to have 10 times lower thd at the same levels of the tube
amp,
say 0.003% because they mainly operate in the middle of the switching region
of the output
transistors, and although the thd is low, its spectra isn't too good..
Since there is no OPT to cause the phase shifts at F extremes, lots of NFB can
be applied,
and hence the thd and resulting IMD is supposed to be inaudible.

Maybe they measure well, these SS amps, but I get a stream of customers
fed up with the raucous sonic efforts of the SS amps they spent so much on.
Or they say the SS amp is clincal and cold, and freezes out the natural warmth

of massed strings and voices, and removes the leading edges off the brass.
I have lent folks tube amps while I fixed their crummy Creeks, and Cambridge
"budget" models,
and they didn't want to return to their SS amps.
The SS problems are not only the due to output stage crossover distortion.
Whilst biasing the output stage of a Camebridge, I was able to
adjust the bias between class C and heavy class A, and no sound change was
obvious,
it was poor at all times, so I put thet down to the input oppamp circuitry,
switches,
connections, capacitor types, etc, and the sound you hear is the sum of many
parts.

Not all SS amps are plain crook, but enough are to give SS a bad name.
One guy wanted to trade in his SS preamp full of oppamps for the tube pre
I had made after he had a listen.
I gently refused, because how would I sell this horror after folks auditioned
the tube pre?
He'd spent $3,000 on SS pre amd power amps, but after a year he could stand it
no longer,
and went to all tubes, how's that for 22 yr old ears?


Patrick Turner.








--
*Keep honking...I'm reloading.

Dave Plowman London SW
To e-mail, change noise into sound.

Valve amp (preferably DIY) to drive apair of Wharfedale DiamondII's
 

Rob wrote:

Think of the amp as a lens - a valve amp 'bends the light' in a
way that allows focus. Some wouldsay distortion, I'd say focus, and it's
the curious sense of space that valve amps relay plus the 'smoothness'.

Ok, its a "lens".

can you explain how your analogy works please because it makes little
sense to me. lenses dont amplify light, they bend or distort it.

Valve amp (preferably DIY) to drive apair of Wharfedale DiamondII's
 

Ian Molton wrote:
Rob wrote:

Think of the amp as a lens - a valve amp 'bends the light' in a

way that allows focus. Some wouldsay distortion, I'd say focus, and
it's the curious sense of space that valve amps relay plus the
'smoothness'.


Ok, its a "lens".

can you explain how your analogy works please because it makes little
sense to me.

The medium through which we 'see' music (the lens analogy) is better
served with valves, sometimes


lenses dont amplify light, they bend or distort it.

I know - they can amplify an object - hence the anaolgy with 'amplifier'.

As you can tell(!) it's difficult (impossible?!) to set this out with
empirical data. Just listen to one.

Rob

Valve amp (preferably DIY) to drive apair of Wharfedale Diamond II's
 

On Sun, 14 Nov 2004 15:06:06 +0000, Rob
wrote:

Jim Lesurf wrote:
In article , Rob
wrote:

Ian Molton wrote:

Ok, in that case, explain to me why you cant seem to even accept the
possibility that (good) SS amps sound 'cold and harsh' due to an
absence of audible distortion.

IMO entire human perception is shrouded in distortion and I find this
whole debate about 'causal distortion' a red herring. Certainly, by
measurement using certain 'rulers', a valve amplifier will provide a set
of measurements different to that of a SS amplifier.

More importantly, the SS amp can produce an output which is audibly
indistiguishable from the input .

I would agree that it does seem to be the case that human physiology means
that our hearing system is quite non-linear, and hence does not always
react as we might think. However I don't think it follows from this that
distortion in audio equipment is a 'red herring'. It can alter the results
in an audible way, and hence must matter if we have an interest in the
results.

Well, I think the red herring is the association. Many of the technical
contributors near enough instantly associate 'the distortion of valve
amps' with 'imperfect sound amplification'. That for me is just not good
enough. Think of the amp as a lens - a valve amp 'bends the light' in a
way that allows focus. Some wouldsay distortion, I'd say focus, and it's
the curious sense of space that valve amps relay plus the 'smoothness'.

Nice technobabble, but basically meaningless.

And anyway, isn't distortion from a valve amp (say 25w) negligible at
decent sound levels (say 5w)?

Indeed, but when you need realistic sound levels from conventional
speakers, it once again raises its ugly head. And if you agree that
low distortion is a good idea , why waste your time with valves in the
first place?

I have no idea on what subject your doctoral thesis is based, but you
certainly don't appear to be making any attempt to 'increase the sum
of human knowledge' in this thread..............

It is my intuitive feeling that many SS amps distort source sound in a
way less benign than that of many valve amps.

But it may be that your "intuative feeling" is simply incorrect as a
description of reality once you use the term "distort" which has a quite
specific definition in the context of measurements on audio equipment. Thus
it may be that your statement is unreliable.

Of course! But please bear in mind:

I have learned this by listening, not measuring.

You don't appear to have learned anything at all, given your
self-contradiction in your previous utterances.

Again, by "learned" here you presumably mean "I have formed this feeling as
it seems consistent with hearing a difference and preferring one sort of
amp".

However would it not also be quite consistent with your experience to say
that you prefer the sound altered in a given way by a valve amp, so simply
miss this when listening to a SS amp? - i.e. it does not tell you anything
about the presence or absence of distortion in a SS amp beyond saying it
does not share the distortion of a valve amp?

More or less, yes. It's just that I'm unhappy with the word 'altered'.
Valve amplification (or at least all that I've heard) just gets me
closer to the essence of what I believe music sounds like. You would say
altered - because the amplified signal deviates from the original
recorded pattern to a greater extent. The incredibly frustrating thing
for scientists is that my explanation has all the credibility of say a
homeopathy advocate. All I can say (again) is have a listen - I can't
explain it.

Well, since homeopathy demonstrably doesn't work, where does that
leave *your* technobabble?

We *do* listen, it seems to be your side that seems to need some kind
of bull**** justification for what is clearly a personal preference
for euphonic distortion, as opposed to the unalloyed sound of the
master tape.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Valve amp (preferably DIY) to drive apair of Wharfedale Diamond II's
 

He'd spent $3,000 on SS pre amd power amps, but after a year he could stand it
no longer, and went to all tubes, how's that for 22 yr old ears?

Nice post, Patrick.

=== Andy Evans ===
Visit our Website:- http://www.artsandmedia.com
Audio, music and health pages and interesting links.

Valve amp (preferably DIY) to drive apair of Wharfedale DiamondII's
 

Stewart Pinkerton wrote:
On Sun, 14 Nov 2004 15:06:06 +0000, Rob
wrote:


Jim Lesurf wrote:

In article , Rob
wrote:


Ian Molton wrote:

Ok, in that case, explain to me why you cant seem to even accept the
possibility that (good) SS amps sound 'cold and harsh' due to an
absence of audible distortion.

IMO entire human perception is shrouded in distortion and I find this
whole debate about 'causal distortion' a red herring. Certainly, by
measurement using certain 'rulers', a valve amplifier will provide a set
of measurements different to that of a SS amplifier.


More importantly, the SS amp can produce an output which is audibly
indistiguishable from the input .


I would agree that it does seem to be the case that human physiology means
that our hearing system is quite non-linear, and hence does not always
react as we might think. However I don't think it follows from this that
distortion in audio equipment is a 'red herring'. It can alter the results
in an audible way, and hence must matter if we have an interest in the
results.


Well, I think the red herring is the association. Many of the technical
contributors near enough instantly associate 'the distortion of valve
amps' with 'imperfect sound amplification'. That for me is just not good
enough. Think of the amp as a lens - a valve amp 'bends the light' in a
way that allows focus. Some wouldsay distortion, I'd say focus, and it's
the curious sense of space that valve amps relay plus the 'smoothness'.


Nice technobabble, but basically meaningless.

Technobabble - high praise!


And anyway, isn't distortion from a valve amp (say 25w) negligible at
decent sound levels (say 5w)?


Indeed, but when you need realistic sound levels from conventional
speakers, it once again raises its ugly head. And if you agree that
low distortion is a good idea , why waste your time with valves in the
first place?

I don't 'agree' - one of the things I maintain is that i don't know. I
do hope that point has sunk in.

I have no idea on what subject your doctoral thesis is based, but you
certainly don't appear to be making any attempt to 'increase the sum
of human knowledge' in this thread..............

Policy implementation - and as you probably know there's a lot of
empirical research in that field correlating finite variables with
outcomes. And it wouldn't surprise you to know that, methodologically at
least, I find it flawed.

The only thing I'm attempting to do in this thread (good point actually
SP) is encourage people to *try* a valve amplifier if they have the
money and inclination, and not dismiss it on the basis of empirical
evidence.


It is my intuitive feeling that many SS amps distort source sound in a
way less benign than that of many valve amps.

But it may be that your "intuative feeling" is simply incorrect as a
description of reality once you use the term "distort" which has a quite
specific definition in the context of measurements on audio equipment. Thus
it may be that your statement is unreliable.


Of course! But please bear in mind:


I have learned this by listening, not measuring.


You don't appear to have learned anything at all, given your
self-contradiction in your previous utterances.

?


Again, by "learned" here you presumably mean "I have formed this feeling as
it seems consistent with hearing a difference and preferring one sort of
amp".

However would it not also be quite consistent with your experience to say
that you prefer the sound altered in a given way by a valve amp, so simply
miss this when listening to a SS amp? - i.e. it does not tell you anything
about the presence or absence of distortion in a SS amp beyond saying it
does not share the distortion of a valve amp?


More or less, yes. It's just that I'm unhappy with the word 'altered'.
Valve amplification (or at least all that I've heard) just gets me
closer to the essence of what I believe music sounds like. You would say
altered - because the amplified signal deviates from the original
recorded pattern to a greater extent. The incredibly frustrating thing
for scientists is that my explanation has all the credibility of say a
homeopathy advocate. All I can say (again) is have a listen - I can't
explain it.


Well, since homeopathy demonstrably doesn't work, where does that
leave *your* technobabble?

Right where I'm happy with it. And incidentally - my reference was
self-deprecating.

We *do* listen, it seems to be your side that seems to need some kind
of bull**** justification for what is clearly a personal preference
for euphonic distortion, as opposed to the unalloyed sound of the
master tape.

I know that you have, and I respect your opinion based on listening -
you've done more than most (including me) to clarify things in your own
mind. My 'bull****' is no more or less than preference - if you think
that arises from distortion, then that's up to you.

Rob