"Jim Lesurf" wrote in message
...
In article , Iain M Churches
wrote:

"Jim Lesurf" wrote in message
...
In article , Iain M Churches
wrote:



Just a few days ago, he invited me to listen to a recording of
Shostakovich String Quartet No.3 Op.73 in F major, on which he
played. He uses a Russian built SET amplifier and a pair of Quad ELS.

Which amplifier, and which speakers?

Slainte,

Jim

The amp was built by a Russian engineer called Anton Reznikov,

OK. As you might guess, I would now wish to know the o/p impedance, etc,
of
these amps as I'm afraid I know nothing about them.

I am afraid I know nothing about them either, except that, with the music
in question they did sound remarkably good. In fact I know very little
about
power triodes. I have since learned that this SET was a type 211.

and the speakers by an English engineer called Peter Walker late 70's?

OK. So I can assume they were one of the issues of the ESL57 as opposed to
a 63 or a 988/989.

That is something I can check. This gentleman is not the original owner,
but
I do know from where these speakers came, and can establish their history.

The obvious point here is that most of the SET amps I have seen reviewed
in
consumer mags have - where a value is given - o/p impedance of around 1
Ohm
even midband at low power.

I seem to recall than Andre told me they sometimes have a DF of 1.

Thus using such an amp rather than one with a low o/p impedance might well
change the frequency response by the order of 3dB. Hardly surprising if
this has an audible effect. Then a matter of circumstances if this is
preferred, I guess...

Yes indeed. I am still intrigued to know how an amplifier with such a poor
test bench specification can sound so good. I have no axe to grind here. I
do not own an SET amp.

The CD player was a Studer A730.

OK. I don't regard that as likely to be particularly significant in this
context.

I mentioned it because I was sure you would ask if I did not:-))

Another interesting point here is that ESLs tend to provide lower
distortion than cone-and-box speakers. Yet SETs tend to provide higher
distortion than common SS amps.

At lowish listening levels, the SET distortion was not even faintly audible.
I daresay that at higher levels it might have been so. I was not invited
to touch the level controls, and did not do so.

Iain