Stewart Pinkerton wrote:
On 19 Dec 2005 15:30:31 -0800, "Andre Jute" wrote:


dave weil wrote:
On Mon, 19 Dec 2005 21:28:36 GMT, "Trevor Wilson"
wrote:

True. A great advantage, much more pleasant than the odd harmonics of
PP even when the latter is at a much lower absolute level.

**Huh? In which universe do you imagine that higher levels of distortion
will lead to greater fidelity?

Where did he talk about "fidelity"? Can you say, "Strawman"?

To be fair, Dave, he talks about "greater fidelity", thought the answer
is still the same. Here is an experiment:

Set up two amplifiers exactly the same in all respects except one is PP
and the other is SE, with just enough distortion on each amplifier to
be perceptible to a refined listener. Spin a disc.

If the two amps are *in fact* the same in all respects, i.e the same
tubes at the same operating point, then the SE amp will have the same
level of odd harmonics as the PP amp - but *much* more 2nd harmonic
than the PP, which of course cancels the even harmonics.

To make the distortion levels 'just perceptible' in each case means
that the SE amp has much *less* basic distortion than the PP amp -
which is of course a completely unrealistic scenario.

Exactly! That is why a silent SE amp, such as I build, sounds so much
better than anything else.

Life isn't fair, Stewart. That's just a normative case they teach in
engineering departments so the students don't run away to become
plumbers and earn real money and retire to Spain (horrid thought) at
35.

Now the SE amp will give you the warm glow that the same music
originally gave you in the concert hall.

No, it will give you a warm glow that *never existed* in the concert
hall - it washes whiter than white.

Hey, persil is good too. I'm outa advertising. The housewife isn't
stupid, she's your wife. The audiophile, at least the one with the
sense to buy tubes, isn't stupid, he's your paymaster.

The PP amp will have that
disturbing edge of odd harmonics. Reduce the level of distortion a
little to below perception. Now the SE amp still sounds great and you
can live with for a long time. But the PP amp is not so comfortable
after a disc or two; it demands attention with a certain edgy quality.

If the distortion is below perception in each case, then the amps will
sound identical.

In your normative case, sure. In real life the SE amp will be ZNFB and
the PP amp will have NFB. After 14 hours (not a random number but the
average number of hours an amp is on in my study every day) the SE amp
will still please but the NFB will not just be audible, it will visible
and threatening. This isn't about numbers but about the discrimination
of taste and experience.

I believe our colonial cousins would insert a 'duuhh'
around here somewhere.......

Proud to be an Australian.

Which offers a window on the concert hall? Which is the amp you want to
live with?

In the second case, they are both just fine, but the SE amp will have
cost much more, so you have less money to spend on speakers.......

Says a guy who bought a Krell! What's more, the discussion above
proceeded from the standpoint that the audiophile in question already
owns Quad ESL of some kind and Tannoy Royal Westminsters too. He's not
spending on speakers any more. I didn't mention that as it was too
obvious.

--
Stewart Pinkerton | Music is Art - Audio is Engineering