Stewart Pinkerton wrote:
On Mon, 18 Jul 2005 22:44:09 +0100, "Keith G"
wrote:


"Dave Plowman (News)" wrote in message
...

In article ,
Eiron wrote:

In the UK? - Yes, with our legacy of 'agricultural' Quads, Leaks,
Mullards
and Radfords (etc.) I reckon we're generally a lot less susceptible to
'cosmetics' than the Yanks, affluent Europeans and the more recent,
nouveau-wotsit Far Eastern valveophiles...

Agricultural? You have listed some jolly decent amplifiers from the days
when distortion was considered A Bad Thing and there was no such thing
as 'valve sound'.

Yes - I wondered about that. And of course in their hey-day there was no
alternative to valves.


There still isn't.... :-)


True enough, it's *extremely* hard to generate that much distortion
with transistors....................

But there wasn't that much distortion from a valve amp in its heyday.
It's only now that snake-oil merchants are deliberately building
distorting amps.
What was the point of the 'Point One' in a Leak Point One?

--
Eiron

"Eiron" wrote


Yes - I wondered about that. And of course in their hey-day there was no
alternative to valves.


There still isn't.... :-)


True enough, it's *extremely* hard to generate that much distortion
with transistors....................

But there wasn't that much distortion from a valve amp in its heyday.
It's only now that snake-oil merchants are deliberately building
distorting amps.



Two things that make me smile are people hurling the word 'distortion' about
like it's a form of leprosy, use of the phrase 'valve sound' and the
pejorative epithet 'snake oil merchants' being used for people catering for
a demand...

For a comprehensive and completely 'non-hysterical' discourse on the subject
have a ganderette at:

http://www.economicexpert.com/a/Valve:amplifier.htm

and:

http://www.economicexpert.com/a/Valve:sound.htm


What was the point of the 'Point One' in a Leak Point One?


Dunno - was it anything to do with the 'Point Oh Three' in my KiT88:

http://www.apah69.dsl.pipex.com/kit88/kit88.htm

???

:-)

"Roy" roy wrote


Although I gather from the sales blurb here and there they're trying
their hardest to do just that these days....???

Stewart Ward who produces the excellent Session guitar amps gets
remarkably close to the sound of classic valve amps using analogue SS
circuits (which makes me wonder about the proliferation of digital
"modelling" amps). I have a couple of his DI boxes and they can be made to
sound remarkably like Marshall stacks or AC30s. They're not 100% accurate
of course


What is...??


- no hum for one thing.


No hum? What's the point of that?

(A valve amp without hum is like meat 'n pertaters with no gravy!! :-)

"Keith G" wrote in message
.. .

"Roy" roy wrote


Although I gather from the sales blurb here and there they're trying
their hardest to do just that these days....???

Stewart Ward who produces the excellent Session guitar amps gets
remarkably close to the sound of classic valve amps using analogue SS
circuits (which makes me wonder about the proliferation of digital
"modelling" amps). I have a couple of his DI boxes and they can be made
to sound remarkably like Marshall stacks or AC30s. They're not 100%
accurate of course


What is...??


- no hum for one thing.


No hum? What's the point of that?

(A valve amp without hum is like meat 'n pertaters with no gravy!! :-)

Er, that's what I said - not 100% accurate (in terms of its impersonation of
a valve amp). Which is why I have a Fender Champ too. I don't play MFSL
vinyl through that though.


Roy.

"Keith G" wrote in message
.. .

"Eiron" wrote


Yes - I wondered about that. And of course in their hey-day there was
no
alternative to valves.


There still isn't.... :-)


True enough, it's *extremely* hard to generate that much distortion
with transistors....................

But there wasn't that much distortion from a valve amp in its heyday.
It's only now that snake-oil merchants are deliberately building
distorting amps.



Two things that make me smile are people hurling the word 'distortion'
about like it's a form of leprosy, use of the phrase 'valve sound' and the
pejorative epithet 'snake oil merchants' being used for people catering
for a demand...

For a comprehensive and completely 'non-hysterical' discourse on the
subject have a ganderette at:

http://www.economicexpert.com/a/Valve:amplifier.htm

and:

http://www.economicexpert.com/a/Valve:sound.htm

Sensibly written stuff I would say. This bit:

"One important aspect of tube sound is the soft ceiling in the dynamic range
of tube amplifiers. A tube radio or tube amplifier will increase in volume
to a point, and then as the volume is further increased, it gently reduces
in volume. Unlike transistor amplifiers, tube amplifiers don't tend to
produce the harsh clipping of saturation and cutoff that transistor
amplifiers do. Thus turning up the volume control, the sound will get louder
and then quieter again in a very smooth and gentle sort of way. This soft
ceiling behaves very much like a dynamic range compressor/limiter.One
important aspect of tube sound is the soft ceiling in the dynamic range of
tube amplifiers. A tube radio or tube amplifier will increase in volume to a
point, and then as the volume is further increased, it gently reduces in
volume. Unlike transistor amplifiers, tube amplifiers don't tend to produce
the harsh clipping of saturation and cutoff that transistor amplifiers do.
Thus turning up the volume control, the sound will get louder and then
quieter again in a very smooth and gentle sort of way. This soft ceiling
behaves very much like a dynamic range compressor/limiter"

explains what I like least about valve amps. They are not capable of
accurately reproducing dynamics - and God knows a lot of SS amps aren't
either. I'm not talking volume here, the lack of dynamic performance is
probably most noticeable in chamber music. In my book there's no substitute
for some serious wattage.

But I accept the point. Most of the serious ills attributed to valve amps
are probably a result of poor design - just like SS.

Roy.

On Thu, 21 Jul 2005 12:10:18 +0100, "Roy" roy wrote:

Sensibly written stuff I would say. This bit:

"One important aspect of tube sound is the soft ceiling in the dynamic range
of tube amplifiers. A tube radio or tube amplifier will increase in volume
to a point, and then as the volume is further increased, it gently reduces
in volume. Unlike transistor amplifiers, tube amplifiers don't tend to
produce the harsh clipping of saturation and cutoff that transistor
amplifiers do. Thus turning up the volume control, the sound will get louder
and then quieter again in a very smooth and gentle sort of way. This soft
ceiling behaves very much like a dynamic range compressor/limiter.One
important aspect of tube sound is the soft ceiling in the dynamic range of
tube amplifiers. A tube radio or tube amplifier will increase in volume to a
point, and then as the volume is further increased, it gently reduces in
volume. Unlike transistor amplifiers, tube amplifiers don't tend to produce
the harsh clipping of saturation and cutoff that transistor amplifiers do.
Thus turning up the volume control, the sound will get louder and then
quieter again in a very smooth and gentle sort of way. This soft ceiling
behaves very much like a dynamic range compressor/limiter"

explains what I like least about valve amps. They are not capable of
accurately reproducing dynamics - and God knows a lot of SS amps aren't
either. I'm not talking volume here, the lack of dynamic performance is
probably most noticeable in chamber music. In my book there's no substitute
for some serious wattage.

But I accept the point. Most of the serious ills attributed to valve amps
are probably a result of poor design - just like SS.

Roy.

Not terribly sensible really.

He says that as you turn up the volume, the sound will get louder, and
then as the volume increases it will reduce in volume. Total nonsense,
of course. As you turn up the volume the sound will continue getting
louder and more distorted. At no point will it start getting softer.

He states that in this way, it behaves like a dynamic range
compressor. No it doesn't - that is an automatic volume control which
need not add any distortion. What a valve amp behaves like, of course,
is a soft clipper - which is what it is.

As regards clipping characteristics, this is also nonsense. With a
solid state amp you just buy one of sufficient power that clipping
doesn't enter the picture - you never get near it. So in comparison
the soft clipping characteristics of valves equate to nothing more
than excess distortion.

As for your last part about the ills of valve amps being due to poor
design, you are absolutely right, but the point is that is really
quite hard and very expensive to design a valve amp properly so it
doesn't do this stuff. For SS, this is done and dusted long ago, and
is trivially easy as well as cheap.

d

Pearce Consulting
http://www.pearce.uk.com

In article , Roy roy wrote:


http://www.economicexpert.com/a/Valve:sound.htm

Sensibly written stuff I would say.

Well, I may beg to differ... :-)

This bit:

"One important aspect of tube sound is the soft ceiling in the dynamic
range of tube amplifiers. A tube radio or tube amplifier will increase
in volume to a point, and then as the volume is further increased, it
gently reduces in volume. Unlike transistor amplifiers, tube amplifiers
don't tend to produce the harsh clipping of saturation and cutoff that
transistor amplifiers do.

This seems to perpetuate the common confusion between

1) 'valves versus transistors' as gain devices.

and

2) the details of the amplifier design that may lead to various behaviours
at clipping or saturation.


Thus turning up the volume control, the sound will get louder and then
quieter again in a very smooth and gentle sort of way.

The implication of the above wording seems to be that the amplifiers are
being clipped or saturated over the entire range of volume settings
involved. This strikes me as dubious, or worrying, depending on your point
of view.


This soft ceiling behaves very much like a dynamic range
compressor/limiter.

Not quite. A compressor/limiter design may monitor the signal level over a
controlled, and variable, time, and adjust the gain accordingly. This may
be quite different in effect to simply allowing nonlinearity to distort the
transfer function.


One important aspect of tube sound is the soft ceiling in the dynamic
range of tube amplifiers. A tube radio or tube amplifier will increase
in volume to a point, and then as the volume is further increased, it
gently reduces in volume. Unlike transistor amplifiers, tube amplifiers
don't tend to produce the harsh clipping of saturation and cutoff that
transistor amplifiers do.

Although it may make more sense if you wish to avoid "harsh clipping" to
simply employ amplifiers that can provide the required signal levels
without the amplifier clipping at all. Once this is done the behaviour in
clipping becomes irrelevant.


Thus turning up the volume control, the sound will get louder and then
quieter again in a very smooth and gentle sort of way.

I would be worried if the volume "got quieter again" as you continued to
increase the actual level. This would imply either a serious problem or a
great deal of nonlinearity. Perhaps the above is not clearly written?...


This soft ceiling behaves very much like a dynamic range
compressor/limiter"

Not quite, as already explained when he said it before. :-)

explains what I like least about valve amps. They are not capable of
accurately reproducing dynamics - and God knows a lot of SS amps aren't
either. I'm not talking volume here, the lack of dynamic performance is
probably most noticeable in chamber music. In my book there's no
substitute for some serious wattage.

But I accept the point. Most of the serious ills attributed to valve
amps are probably a result of poor design - just like SS.

I think that is the key point.

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 ,
Roy roy wrote:
Sensibly written stuff I would say. This bit:

"One important aspect of tube sound is the soft ceiling in the dynamic
range of tube amplifiers. A tube radio or tube amplifier will increase
in volume to a point, and then as the volume is further increased, it
gently reduces in volume. Unlike transistor amplifiers, tube amplifiers
don't tend to produce the harsh clipping of saturation and cutoff that
transistor amplifiers do.

This is only important because it's hideously expensive to produce a valve
amp with the sort of power now taken for granted with modest SS amps.

So to avoid clipping, you simply need an amp with enough power. And no
true audio enthusiast wants any part of the chain to clip.

Thus turning up the volume control, the sound will get louder and then
quieter again in a very smooth and gentle sort of way. This soft ceiling
behaves very much like a dynamic range compressor/limiter.

This is nonsense. A compressor limiter of decent design doesn't introduce
those levels of distortion.

--
*Why do overlook and oversee mean opposite things?

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