So what are the best Chinese valve amps???
 

"Iain Churches" wrote in message
i.fi...

"Keith G" wrote


Fine, but when people start quoting 'distortion figures' for valve
amps
(SETs in particular) it seems to me that it's bit like getting
carried
away with the E numbers listed on the label and the taste of the
actual
item is quickly forgotten.

It seems that the THD itself is not so important as the way
in which that total is made up, i.e. the relationship of
2H,3H,4H,5H etc that is important. It may be this which
gives each amp its sonic signature.


Quite possibly - I couldn't comment, it's over my head; I can't get past
the mental image of *happy/liberated electrons* flying about in a big
triode!! :-)




Also, to imply SET can't do much more than play female vocals and
small
chamber ensembles is more than a little misleading, IMO!

Many people seem to agree that is what they are best at.
I share that opinion. As I have mentioned before the
Resnekov plays Shostakovich like I have never heard it before.


OK, but 'best at' is different to 'can't' which is what is often
implied - although I'm not saying you implied it!.


Low power SET amps can drive 'normal' speakers of modest sensitivity
but
not to great levels with the result that, although it may be
interesting
to do, it is mostly a futile exercise. That said, I would only ever
say to
someone to try it - not everyone plays music/movies as loud as I
often do!

Understood.


Some time after I posted last night, I hooked my 3.5W SET up to the IMF
TLS80s (no idea what the sensitivity figure for those is offhand!) and
the sound, with the SET being driven by the Technics Control Amp, was
very pleasant/extremely listenable and could go plenty loud enough for
most!


I don't listen to DAB radio and so cannot comment.


During the day for sonic wallpaper and the evenings if FM is feeling
'chesty', DAB isn't as bad as some people would make out. Consider it
not unlike the difference between LP and CD! ;-)


Good PP valve amps can sound as good as a SET on horns and will have
more
clout, but are not as beguiling/listenable in the long run

Yes that seems to be a widely held view - especially by those who
have become enraptured with SET.


'Enraptured' is a strong word.....



But do not forget what is perhaps the main reason why SET is so
popular
with DIY builders. It is (up to a certain level) very simple to
build, requiring


Yes.



little or no test equipment.


Yes.


There is every chance the amp will work first
time


Yes (but some hum)!



without the stability problems that lurk inherently in every tube PP
amplifier.


Ah! OK, did that as well (from a kit)!!



while
CDs are always improved by any valve amp (on the appropriate
speakers), no
matter what....

I will leave it to someone else to reply to that para:-) I am not
sure
how a CD can be "improved" It can certainly be made to sound
different.


Quite simple: Play a CD on a SET/horns setup and it 'acquires' depth,
space, clarity and warmth and can become 'engaging'; play it on a
'standard' SS arrangement and it becomes two dimensional and will become
easy to walk away from....


I use a PP amp because it can make a good job of most material.
I do not claim it is more accurate than (or even as accurate as) the
Crown Macrotech usually used in monitoring recordings, but it
certainly gives a very musical rendition.


The SS Technics amps I have here have some of the lowest distortion
figures on record according to a (May 1999 HFN&RR) magazine review:

http://www.apah69.dsl.pipex.com/show/Amps01.JPG

http://www.apah69.dsl.pipex.com/show/Amps02.JPG

http://www.apah69.dsl.pipex.com/show/Amps03.JPG


And I can haul 'commercial' speakers from Ruark, Tannoy, B&W and IMF to
them without breaking a sweat as well as scrounge no end of others from
friends and at least one of the two local 'hifi' shops! Add to that I
have Sheffield Labs CDs here and a dozen different ways of playing them
(or do I? - make that half a dozen) and I think you'll agree I'm not
stuck with a *SET/LP only* situation!!??



I would also like to have SET (and plan to discuss a design with Nick
when the time is right) for playing certain types of music.


Well, OK then - that's what *we* all do at the outset; the problems
begin when you start *preferring* the sound from a SET system!!

;-)


You are preaching to the converted here, Keith.
You will recall not long ago I reported on both my visit to
the Lowther group, and also my experiences with the Resnekov.
But still I wanted to *see* why the two amps
sound different. I think I know now.


I'm sorry if I seem to be preaching at all - my reaction to criticism
of/comment on SET amps is a fairly standard one, usually brought about
by silly remarks made by people who don't think we (SET users) have any
experience of or access to other, more 'normal' amplification systems
(as above)!!

So what are the best Chinese valve amps???
 

"tony sayer" wrote in message
...
In article , Keith G
scribeth thus

"tony sayer" wrote in message
...
In article , Keith G
scribeth thus

"Arny Krueger" wrote in message
news:O92dnQ3LxfY5wZzanZ2dnUVZ_oGjnZ2d@comcast. com...
"Keith G" wrote in message


SS amps rarely (if ever) sound very good on 'horns' and
it's almost always a waste of time.

Strange since SS amps are widely used in pro sound applications
with
horns, and they can sound wonderful.


OK, it's a quick 'banana plug' chop so *just for you* I wired my
Fidelios to the Technics SS (MOSFET) amp to revisit/check and it's
been
very interesting....

Better than I remember, I hafta say, with a lot more bass (and
low-level
noise) from FM Radio which could well be down to the fact that the
Fidelios seem to have 'come of age' recently and have found a lot
more
bass. CD still suffers comparative loss of image and spaciality
(that
planar quality creeping in again) and vinyl just sounded *tired*,
but
that was on the Control Amp's own SS phono stage which could well
explain that! -



DAB radio was probably the best of the lot!!

Jesus Keith!, what are you -on- there?!.....


Classic FM, asitappens - far too much 'slurry' on FM tonight!!



You need a decent erection I reckon!, got the best tuner in the world
and feed it with a bit of damp string or that cowboy frigged
aerial!...


:-)

I normally get a reading of 55-60 dBf - Serge calculated that I would
need 80 dBf for a *silent* signal which, I believe would take care of
any hiss which is not usually a problem, but I don't think it would
remove the low-level 'wind in the microphone' that I get from time to
time?

(Get another floorboard up you tight sod and you could have the 'best
tuner in the world' and I'd get shot of the biggest piece of kit I've
got here!! :-)

So what are the best Chinese valve amps???
 

On 2007-10-02, Don Pearce wrote:
On Tue, 2 Oct 2007 09:51:32 +0300, "Iain Churches"
wrote:

It seems that the THD itself is not so important as the way
in which that total is made up, i.e. the relationship of
2H,3H,4H,5H etc that is important. It may be this which
gives each amp its sonic signature.

Harmonic distortion itself is really not so important for music, which
is loaded with harmonics anyway. What matters is that distortion - any
distortion, even or odd - produces intermods. These products are
non-harmonic and certainly for music with any degree of complexity
will be dissonant. If the distortion level is moderately low, the
result will just be a sort of "thickening" of the sound, which may
indeed be more interesting than the unadorned music.

I have sometimes pondered (without real cause, I admit) about whether the
"usual" IMD tests are good enough as a predictor of audible IMD effects.

Do you think the normal two-tone IMD tests (from SMPTE, DIN, IEC,
etc.) provide an adequate basis for testing something where (I postulate)
more complex IMDs may be the more audible effect?

--
John Phillips

So what are the best Chinese valve amps???
 

On 02 Oct 2007 12:33:43 GMT, John Phillips
wrote:

On 2007-10-02, Don Pearce wrote:
On Tue, 2 Oct 2007 09:51:32 +0300, "Iain Churches"
wrote:

It seems that the THD itself is not so important as the way
in which that total is made up, i.e. the relationship of
2H,3H,4H,5H etc that is important. It may be this which
gives each amp its sonic signature.

Harmonic distortion itself is really not so important for music, which
is loaded with harmonics anyway. What matters is that distortion - any
distortion, even or odd - produces intermods. These products are
non-harmonic and certainly for music with any degree of complexity
will be dissonant. If the distortion level is moderately low, the
result will just be a sort of "thickening" of the sound, which may
indeed be more interesting than the unadorned music.

I have sometimes pondered (without real cause, I admit) about whether the
"usual" IMD tests are good enough as a predictor of audible IMD effects.

Do you think the normal two-tone IMD tests (from SMPTE, DIN, IEC,
etc.) provide an adequate basis for testing something where (I postulate)
more complex IMDs may be the more audible effect?

Depends what you mean by testing. From a single harmonic distortion
measurement I can predict two, three, four tone intermodulation
performance accurately, given the right data from the harmonic
measurement.

Harmonics and intermodulation are simply the inevitable and calculable
results of a crooked transfer function. So is a normal two-tone IM
measurement sufficient? I would have to say yes, more than enough.

The published result (in % or dB) of a harmonic distortion measurement
is not adequate in itself.

d

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

So what are the best Chinese valve amps???
 

On 2007-10-02, Don Pearce wrote:
On 02 Oct 2007 12:33:43 GMT, John Phillips
wrote:
I have sometimes pondered (without real cause, I admit) about whether the
"usual" IMD tests are good enough as a predictor of audible IMD effects.

Do you think the normal two-tone IMD tests (from SMPTE, DIN, IEC,
etc.) provide an adequate basis for testing something where (I postulate)
more complex IMDs may be the more audible effect?

Depends what you mean by testing. From a single harmonic distortion
measurement I can predict two, three, four tone intermodulation
performance accurately, given the right data from the harmonic
measurement.

Harmonics and intermodulation are simply the inevitable and calculable
results of a crooked transfer function. So is a normal two-tone IM
measurement sufficient? I would have to say yes, more than enough.

The published result (in % or dB) of a harmonic distortion measurement
is not adequate in itself.

Yes - that was a concern I had and FWIW I think you must be right.

I was also concerned over checking properly the ability of a system to
accurately reproduce low-level signals in the presence of high-level
signals and whether this result could be deduced from simple two-tone
IMD tests (but with full graphic results - not single summed figures).

--
John Phillips

So what are the best Chinese valve amps???
 

On 02 Oct 2007 13:16:53 GMT, John Phillips
wrote:

On 2007-10-02, Don Pearce wrote:
On 02 Oct 2007 12:33:43 GMT, John Phillips
wrote:
I have sometimes pondered (without real cause, I admit) about whether the
"usual" IMD tests are good enough as a predictor of audible IMD effects.

Do you think the normal two-tone IMD tests (from SMPTE, DIN, IEC,
etc.) provide an adequate basis for testing something where (I postulate)
more complex IMDs may be the more audible effect?

Depends what you mean by testing. From a single harmonic distortion
measurement I can predict two, three, four tone intermodulation
performance accurately, given the right data from the harmonic
measurement.

Harmonics and intermodulation are simply the inevitable and calculable
results of a crooked transfer function. So is a normal two-tone IM
measurement sufficient? I would have to say yes, more than enough.

The published result (in % or dB) of a harmonic distortion measurement
is not adequate in itself.

Yes - that was a concern I had and FWIW I think you must be right.

I was also concerned over checking properly the ability of a system to
accurately reproduce low-level signals in the presence of high-level
signals and whether this result could be deduced from simple two-tone
IMD tests (but with full graphic results - not single summed figures).

That also comes out of the basic linearity test. Any system that can't
do that will reveal it in an IM test.

Some systems do this deliberately of course. MP3 codecs work this way
using the phenomenon called masking. Even moderately large signals
close in frequency to very large ones can be deleted inaudibly.

d

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

So what are the best Chinese valve amps???
 

"John Phillips" wrote
in message

I have sometimes pondered (without real cause, I admit)
about whether the "usual" IMD tests are good enough as a
predictor of audible IMD effects.

Not really.

Do you think the normal two-tone IMD tests (from SMPTE,
DIN, IEC, etc.) provide an adequate basis for testing something
where (I postulate) more complex IMDs may be the more
audible effect?

Not really.

Swept 2-tone tests are more to the point.

Multitone-based tests can also work well. Do it right and you can get a
good fast FR test and a good test for nonlinear distortion at all audible
frequencies done with one test, two analyses.

So what are the best Chinese valve amps???
 

"Jim Lesurf" wrote in message
...
In article , Don Pearce
wrote:
On Tue, 2 Oct 2007 09:51:32 +0300, "Iain Churches"

wrote:

It seems that the THD itself is not so important as the way in which
that total is made up, i.e. the relationship of 2H,3H,4H,5H etc that
is
important. It may be this which gives each amp its sonic signature.

Harmonic distortion itself is really not so important for music,
which
is loaded with harmonics anyway. What matters is that distortion -
any
distortion, even or odd - produces intermods. These products are
non-harmonic and certainly for music with any degree of complexity
will
be dissonant. If the distortion level is moderately low, the result
will
just be a sort of "thickening" of the sound, which may indeed be more
interesting than the unadorned music.

For a few minutes, that may be attractive, but after a very short
time I
find it starts to get tiring because the effect doesn't change, there
is
just this permanent grunge underlying everything.

I have started wondering if there is a parallel with adding 'brown
sauce'
to a plate of food. Does this parallel only make sense in the UK?...
:-)


Freudian slip? :-)

So what are the best Chinese valve amps???
 

"Arny Krueger" wrote in message
. ..
"John Phillips" wrote
in message

I have sometimes pondered (without real cause, I admit)
about whether the "usual" IMD tests are good enough as a
predictor of audible IMD effects.

Not really.

Agreed. They must be better than nothing, but probably have
little bearing on what might be happening in a complex musical
signal.

Do you think the normal two-tone IMD tests (from SMPTE,
DIN, IEC, etc.) provide an adequate basis for testing something
where (I postulate) more complex IMDs may be the more
audible effect?

Not really.

There seem to be several opinions regarding the
frequencies of the fundamentals used in such tests.
Is there any standard?
I have seen 70Hz and 6kHz mentioned, and
also 19kHz and 20kHz.

Swept 2-tone tests are more to the point.

Much more like music.

Multitone-based tests can also work well.

Multitone is indeed interesting:-)
Are there any recommendation for centre frequencies?

Iain

So what are the best Chinese valve amps???
 

On 2007-10-02, Iain Churches wrote:
"Arny Krueger" wrote in message
. ..
"John Phillips" wrote
in message

I have sometimes pondered (without real cause, I admit)
about whether the "usual" IMD tests are good enough as a
predictor of audible IMD effects.

Not really.

Agreed. They must be better than nothing, but probably have
little bearing on what might be happening in a complex musical
signal.

That's what has always concerned me. I no longer design and build kit
(for 20 or more years and it was only ever a hobby). Although I got
to understand linear distortions and noise in audio systems I never did
get to grips with understanding non-linear distortion. Of course I
did understand the basics but I always felt the simple IMD tests were
not the complete way to evaluate system non-linearities. However I'm
not really sure.

Do you think the normal two-tone IMD tests (from SMPTE,
DIN, IEC, etc.) provide an adequate basis for testing something
where (I postulate) more complex IMDs may be the more
audible effect?

Not really.

There seem to be several opinions regarding the
frequencies of the fundamentals used in such tests.
Is there any standard?
I have seen 70Hz and 6kHz mentioned, and
also 19kHz and 20kHz.

See, for example, http://www.rane.com/par-i.html (look down for IM/IMD)
for some of the standard IMD test methods.

--
John Phillips