Read the whole article at http://www.aloha-audio.com/library/FindingCG.html

excerpt - "try and find a transistor circuit that can deliver 50V rms at less
than 1% distortion with no feedback!"


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

Excerpt - Lynn Olsen

This brief discussion of amplifiers is intended to point out how traditional
measurements result in unwise decisions for amplifier design. The lower
harmonics are nearly inaudible compared to the upper harmonics, yet they
dominate almost any THD measurement! The meter is steering the designer, the
reviewer, the dealer, and the consumer away from good sound.

It’s the classic tale of a drunk looking for his car keys under the
street-light, even though he suspects he lost them in a completely different
place. "The light is better here!" say the mainstream engineers,
mass-marketers, and magazine reviewers — but the key to good sound sure
isn’t where the audio industry has been looking.

If it were, why do stereo LP’s made 40 years ago, amplified with 65-year-old
direct-heated triodes, sound so much better than today’s digital sound played
through 0.001% THD mass-fi rack stereos? The differences between mass-fi and
true high fidelity are as plain as day to an (open-minded) listener.

We are in the odd position of discovering that as speakers get better and
better, the true merits of vacuum-tube circuits become more and more evident.
After all, even J. Gordon Holt gave the Crown DC-300 transistor amplifier a
Class "A" rating in 1971. At the time, the modestly-priced Dyna Stereo 70
received a lower rating - yet with modern speakers, the DC-300 is unlistenable,
and the Dyna just keeps sounding better. The entry-level EL84 amps of the early
Sixties (Scott 299, Eico, and Dyna SCA-35) sound remarkably natural and
realistic with today’s more efficient, and much more transparent, speakers.

There is no reason to believe speakers will stop getting better, since all
kinds of new innovations in materials science are on the horizon, and there are
major advances in computer modelling techniques every year. Synthetic diamond
cones, anyone?

It’s time to debunk the myth of "euphonic distortion" once and for all and
discover the genuine and subtle sources of amplifier distortion that people are
actually hearing. Once we find measurements that can actually help, rather than
hinder, it'll be easier to build electronics that are friendly to the listener

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

In article , Andy Evans
wrote:
Read the whole article at
http://www.aloha-audio.com/library/FindingCG.html

If I get a chance I'll have a look. :-)

excerpt - "try and find a transistor circuit that can deliver 50V rms at
less than 1% distortion with no feedback!"

If they mean "into a loudspeaker load with an impedance between 4 and 8
Ohms" when considering domestic audio power amps, then I suspect you could
match this with:

"try to find a *valve* circuit that can deliver 50V rms at less than 1%
distortion and no feedback.!"

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

In article , Andy Evans
wrote:
Excerpt - Lynn Olsen

This brief discussion of amplifiers is intended to point out how
traditional measurements result in unwise decisions for amplifier
design.

This may be the case for both transistor and valve based amplifiers.
Depends upon the care with which measurements are made, how well they are
interpreted, and how relevant they may be to actual use with music.


The lower harmonics are nearly inaudible compared to the upper
harmonics,

The above statement makes various unspecified assumptions about the kind of
musical signal patterns being used, the other equipment, and the hearing of
the individual listener. Also about the actual levels of distortion, etc,
etc.

yet they dominate almost any THD measurement! The meter is
steering the designer, the reviewer, the dealer, and the consumer away
from good sound.

That may be the case if the measurement fails to be appropriate and the
person reading the resulting values does not assess their relevance.
However if the distortion *is* low even with musical signals, then this
should not be a factor unless someone *likes* distortion. :-)

It's the classic tale of a drunk looking for his car keys under the
street-light, even though he suspects he lost them in a completely
different place. "The light is better here!" say the mainstream
engineers, mass-marketers, and magazine reviewers - but the key to good
sound sure isn't where the audio industry has been looking.

I am not personally surprised if someone says that many reviews in
magazines are of doubtful value. However I'd tend to apply this to many
'reviews' which go no measured results at all, just as I would to those
which do, but fail to ensure they are relevant.

If it were, why do stereo LP's made 40 years ago, amplified with
65-year-old direct-heated triodes, sound so much better than today's
digital sound played through 0.001% THD mass-fi rack stereos?

Good question. :-) I'm not sure everyone here would offer the same
answer, though. One possibility is that people may sometimes actually
prefer a sound which is distorted or altered in some ways, whereas other
may not like such changes.


Another possibility is that such 'mass-fi' might use lousy
speakers, etc. No doubt there are other possibilities... :-)

The differences between mass-fi and true high fidelity are as plain as
day to an (open-minded) listener.

Maybe I am not as open-minded as I thought. My experience is that this
varys from case to case and I would be reluctant to make such a general
statement as if it were invariably correct.

We are in the odd position of discovering that as speakers get better
and better, the true merits of vacuum-tube circuits become more and more
evident.

Not sure who "we" are here... :-) FWIW I use electrostatic speakers, but
prefer a transistor amp. So far as I am concerned this does not 'prove'
anything much beyond being what I prefer. ;-

After all, even J. Gordon Holt gave the Crown DC-300 transistor
amplifier a Class "A" rating in 1971. At the time, the modestly-priced
Dyna Stereo 70 received a lower rating - yet with modern speakers, the
DC-300 is unlistenable, and the Dyna just keeps sounding better. The
entry-level EL84 amps of the early Sixties (Scott 299, Eico, and Dyna
SCA-35) sound remarkably natural and realistic with today's more
efficient, and much more transparent, speakers.

The above seems to assume I am American or have lived there. Since this is
not so for me, and I have no real personal experience of the amps quoted I
can't comment.

It's time to debunk the myth of "euphonic distortion" once and for all

This may require evidence, though, as opposed to simple assertion. ;-

and discover the genuine and subtle sources of amplifier distortion that
people are actually hearing.

Indeed.

Once we find measurements that can actually help, rather than hinder,
it'll be easier to build electronics that are friendly to the listener

Hard to argue against that as a generalisation. May well lead to better
units of all types.

TBH I'm not quite sure why the above is meant to be a serious argument for
valve amps being 'better' than transistor ones. Seems to simply be saying
that any measurements need to be relevant and correctly understood. Beyond
that, it just seems to be some personal assertions. Have I missed
something?

FWIW I have no argument with, for example, proposals that simple THD is of
limited value in many cases. Just did a webpage on that. :-) Indeed, it
throws a nice light on 'valve' topologies and gives an argument that could
be said to be in their favour... :-)

Also curious that this posting and a previous one seem to focus on one form
of 'distortion' and ignore other factors - e.g. the relatively high output
impedance of many valve amps compared with typical transistor ones.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

"Andy Evans" wrote in message

Excerpt - Lynn Olsen

This brief discussion of amplifiers is intended to point out how
traditional measurements result in unwise decisions for amplifier
design. The lower harmonics are nearly inaudible compared to the
upper harmonics, yet they dominate almost any THD measurement! The
meter is steering the designer, the reviewer, the dealer, and the
consumer away from good sound.

Again, so far, so good.

It's the classic tale of a drunk looking for his car keys under the
street-light, even though he suspects he lost them in a completely
different place. "The light is better here!" say the mainstream
engineers, mass-marketers, and magazine reviewers - but the key to
good sound sure isn't where the audio industry has been looking.

If it were, why do stereo LP's made 40 years ago, amplified with
65-year-old direct-heated triodes, sound so much better than today's
digital sound played through 0.001% THD mass-fi rack stereos? The
differences between mass-fi and true high fidelity are as plain as
day to an (open-minded) listener.

Absolute bunkum.

We are in the odd position of discovering that as speakers get better
and better, the true merits of vacuum-tube circuits become more and
more evident. After all, even J. Gordon Holt gave the Crown DC-300
transistor amplifier a Class "A" rating in 1971. At the time, the
modestly-priced Dyna Stereo 70 received a lower rating - yet with
modern speakers, the DC-300 is unlistenable, and the Dyna just keeps
sounding better. The entry-level EL84 amps of the early Sixties
(Scott 299, Eico, and Dyna SCA-35) sound remarkably natural and
realistic with today's more efficient, and much more transparent,
speakers.

Absolute bunkum.

There is no reason to believe speakers will stop getting better,
since all kinds of new innovations in materials science are on the
horizon, and there are major advances in computer modelling
techniques every year. Synthetic diamond cones, anyone?

True, although there's no evidence that diamond cones would provide audible
advantages.

It's time to debunk the myth of "euphonic distortion" once and for
all and discover the genuine and subtle sources of amplifier
distortion that people are actually hearing.


Via DBTs we know that most "amplifier distortion" exists only in people's
heads.

Once we find
measurements that can actually help, rather than hinder, it'll be
easier to build electronics that are friendly to the listener

Electronics aren't the problem - speakers and microphones are. We don't even
know what an ideal speaker and microphone should do, let alone make one.

On 22 Jul 2003 13:05:13 GMT, ohawker (Andy
Evans) wrote:

Excerpt - Lynn Olsen

snip

If it were, why do stereo LP’s made 40 years ago, amplified with 65-year-old
direct-heated triodes, sound so much better than today’s digital sound played
through 0.001% THD mass-fi rack stereos?

Two points he

* this is a highly subjective statement ("sound much better" is
entirely in the perception of the listener - some may agree with this,
others disagree)

* the LPs of 40 years ago were made on using technology that can only
be considered crude by today's standards, and they were made to be
played using equipment that, in most cases, would be put to shame by a
contemporary no-name mini system (I still recall my father's delight
at having his Decca record player retrofitted w/ a stereo cartridge,
one channel of which went through the original amp and (built-in)
speaker, the other to a matching box w/ a second amp and speaker). If
40 year old recordings sound poor on modern equipment, maybe that's
because the latter does all too good a job of revealing the
inadequacies of the former.

The differences between mass-fi and
true high fidelity are as plain as day to an (open-minded) listener.

We are in the odd position of discovering that as speakers get better and
better, the true merits of vacuum-tube circuits become more and more evident.
After all, even J. Gordon Holt gave the Crown DC-300 transistor amplifier a
Class "A" rating in 1971. At the time, the modestly-priced Dyna Stereo 70
received a lower rating - yet with modern speakers, the DC-300 is unlistenable,
and the Dyna just keeps sounding better. The entry-level EL84 amps of the early
Sixties (Scott 299, Eico, and Dyna SCA-35) sound remarkably natural and
realistic with today’s more efficient, and much more transparent, speakers.

Given that the components referred to above are US in origin, and US
"mass-fi" equipment has been historically a very poor cousin of UK
equivalents, I'm not sure how valid this comparison is.

Julian

--
Julian Fowler
julian (at) bellevue-barn (dot) org (dot) uk

"Julian Fowler" wrote in message
...
On 22 Jul 2003 13:05:13 GMT, ohawker (Andy
Evans) wrote:

snip snip

* the LPs of 40 years ago were made on using technology that can only
be considered crude by today's standards, and they were made to be
played using equipment that, in most cases, would be put to shame by a
contemporary no-name mini system (I still recall my father's delight
at having his Decca record player retrofitted w/ a stereo cartridge,
one channel of which went through the original amp and (built-in)
speaker, the other to a matching box w/ a second amp and speaker). If
40 year old recordings sound poor on modern equipment, maybe that's
because the latter does all too good a job of revealing the
inadequacies of the former.
Julian

--
Julian Fowler
julian (at) bellevue-barn (dot) org (dot) uk

My 'reference' recordings are an old Louis Armstrong LP (50s I think) and an
original of Let it Bleed (66?). The quality (as well as the music let's not
forget!) is superb. Much of the late beatles stuff is pretty hq IMHO (cd and
LP). I bought a few remastered Hendrix cds a couple of years ago and the
quality compared to the record is diabolical - compressed and flat. They
must have got something right 40 years ago after all, at least to my mind.

Don't know about all the valve stuff I'm afraid. Don't understand the
technical bits and never had the opportunity to listen. But if nothing else
it's made me think that there might be something in it after all given the
'passion' here ;-)

Rob

"Julian Fowler" wrote in message


* the LPs of 40 years ago were made on using technology that can only
be considered crude by today's standards, and they were made to be
played using equipment that, in most cases, would be put to shame by a
contemporary no-name mini system (I still recall my father's delight
at having his Decca record player retrofitted w/ a stereo cartridge,
one channel of which went through the original amp and (built-in)
speaker, the other to a matching box w/ a second amp and speaker). If
40 year old recordings sound poor on modern equipment, maybe that's
because the latter does all too good a job of revealing the
inadequacies of the former.

Amen, brother.

On 22 Jul 2003 12:07:09 GMT, ohawker (Andy
Evans) wrote:

Read the whole article at http://www.aloha-audio.com/library/FindingCG.html

excerpt - "try and find a transistor circuit that can deliver 50V rms at less
than 1% distortion with no feedback!"

Try and find any valve circuit that can do this - into a speaker
load......

*All* amps use feedback, but some don't use *global* feedback, leading
to a common claim about 'zero feedback' valve amps.

BTW, the answer to your question is any Krell FPB series amp from the
FPB300 up. They don't use global feedback. Also, there are damn few
valve amps capable of delivering 300 watts to an 8 ohm load, which
requires 49 volts rms. There are however many such SS amps - and they
can maintain their output voltage much better into real-world speaker
loads which dip to 3 ohms or less.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On 22 Jul 2003 13:05:13 GMT, ohawker (Andy
Evans) wrote:

Excerpt - Lynn Olsen

This brief discussion of amplifiers is intended to point out how traditional
measurements result in unwise decisions for amplifier design. The lower
harmonics are nearly inaudible compared to the upper harmonics, yet they
dominate almost any THD measurement! The meter is steering the designer, the
reviewer, the dealer, and the consumer away from good sound.

It’s the classic tale of a drunk looking for his car keys under the
street-light, even though he suspects he lost them in a completely different
place. "The light is better here!" say the mainstream engineers,
mass-marketers, and magazine reviewers — but the key to good sound sure
isn’t where the audio industry has been looking.

See Jim's post for a good debunk of the above.

If it were, why do stereo LP’s made 40 years ago, amplified with 65-year-old
direct-heated triodes, sound so much better than today’s digital sound played
through 0.001% THD mass-fi rack stereos?

Who says that they do?

The differences between mass-fi and
true high fidelity are as plain as day to an (open-minded) listener.

Very true, but luckily true high fidelity can now be had for
mass-market money - if you avoid valves, of course.......

We are in the odd position of discovering that as speakers get better and
better, the true merits of vacuum-tube circuits become more and more evident.

What 'merits'?

After all, even J. Gordon Holt gave the Crown DC-300 transistor amplifier a
Class "A" rating in 1971. At the time, the modestly-priced Dyna Stereo 70
received a lower rating - yet with modern speakers, the DC-300 is unlistenable,
and the Dyna just keeps sounding better.

Er no, the Dyna keeps sounding warm and mushy, like it always did. You
can't just jump from 'true high fidelity' to the classic rose-tinted
sound of the Strereo 70 without comment.

The entry-level EL84 amps of the early
Sixties (Scott 299, Eico, and Dyna SCA-35) sound remarkably natural and
realistic with today’s more efficient, and much more transparent, speakers.

Yes, and so do small Class A SS amps like the Sugdens.

There is no reason to believe speakers will stop getting better, since all
kinds of new innovations in materials science are on the horizon, and there are
major advances in computer modelling techniques every year. Synthetic diamond
cones, anyone?

Very true, and they will continue to expose the technical deficiencies
of valve amps.......

It’s time to debunk the myth of "euphonic distortion" once and for all and
discover the genuine and subtle sources of amplifier distortion that people are
actually hearing. Once we find measurements that can actually help, rather than
hinder, it'll be easier to build electronics that are friendly to the listener

Even better, use SS amps which often have distortion products well
below their (very low) noise floor...............

I'll happily put up my trusty old Audiolab 8000P against *any* valve
amp at *any* price.
--

Stewart Pinkerton | Music is Art - Audio is Engineering