"Andre Jute" wrote in message
ups.com
Dave Plowman (News) wrote:

Judging by the many posts about SET etc designs on here
there again seems to be a wish to modify the incoming
signal rather than just amplify it.

Do you really believe that, Dave?

It's a fact. Or is it that John Atkisnon is publishing lies about the
measured perforamnce of the SETs his ragazine reviews?

I thought you were in
the recording business. Surely you know that now amp
whatsoever merely processes the signal blamelessly. Those
with negative feedback, for instance, add artifacts to
the music, higher order harmonics.

Darn that John Atkinson! Why is it that the SET amps he reviews have far
more high order harmonics than a good SS amp with loop feedback?

For example:

http://www.stereophile.com/amplifica...ac/index5.html

Figure 8:

Harmonic - distortion
2 -28 dB
3 -38 dB
4 -60 dB
5 -62 dB
6 -60 dB
7 -62 dB
8 -83 Db (strange anomoly at 420 Hz)
9 -90 dB
10 -95 dB
11 -62 dB
12 -90 dB
13 -68 dB
14 -90 dB
15 -62 dB
16 -100 dB
17 -90 dB
18 -72 dB

Since when is not the 18th harmonic a higher order harmonic?

I don't actually want to modify the incoming signal.


Then get a good SS amp with reasonable amounts of loop feedback!

Compare the above to the Adcom GFA 7805
http://stereophile.com/solidpoweramp...om/index4.html

Figure 8:

Harmonic - distortion
2 -95 dB
3 -82 dB
4 -110 dB
5 -90 dB
6 -100 dB
7 -98 dB
8 -105 dB
9 -105 dB
10 -115 dB
11 -115 dB
12 -102 dB
13 -110 dB
14 -120 dB
15 -110 dB
16 -110 dB
17 -100 dB
18 -112 dB


What
I want is an outcoming signal that sounds more like the
concert hall than what the engineers now give me.

So how is adding audible noise and distortion going to help that?

One way
of doing that is by having a very silent class A sound
from devices operated along only the most linear part of
their transfer curve, and tilting the transfer so that
the odd and higher harmonics become a smaller part of the
mix than before.

Wrong - the Adcom above has far less of every order of distortion than the
Wavac.

Your way of thinking appears to hold it
axiomatic that a solid state device is a paradigm of fine
sound. If the paradigm doesn't satisfy, for whatever
reason, it is time to trade it in for one that works. The
one that works a lot better is Class A operated at high
voltage and high current into a high impedance with
little or no negative feedback.

The facts say otherwise.