On Tue, 14 Dec 2004 11:25:59 +0200, "Iain M Churches"
wrote:


"Stewart Pinkerton" wrote in message
.. .
On Mon, 13 Dec 2004 23:27:18 +0200, "Iain M Churches"
wrote:

It obviously depends on the bandwidth of the amp, which doesn't have
much to do with 'high end' credentials.

Understood:-)
But I assumed the better the amp the better the performance.

That depends how you define 'batter'. The Spectral for instance has
megahertz bandwidth, so immaculate phase response at 20kHz, but is
notoriously unstable. The Naim OTOH has been highly regarded by
audiophiles for about thirty years, despite being sensitive to
capacitive lopads and demanding highly inductive speaker cable to
maintain its warranty. VCome to think of it, the phase response is a
lot worse if you include that cable, as you should since Naim consider
iot to be an essential part of the circuit driving the speaker.
Basically, there's a *lot* more to 'high fidelity' than sheer
bandwidth. Many decades ago, the brilliant Gilbert Briggs of
Wharfedale coined a very useful phrase - the wider you open the
window, the more the muck flies in!

An initial investigation of my 50W amplifier which has the first and second
stages DC coupled, shows -3 degrees at 10Hz, and -8 degrees at 50kHz.
So about the same as the Audiolab 8000P, and very close to the Spectral?
Not too shabby:-))

That's very impressive for a valve amp.

This amp has custom-designed Sowter transformers. A similar amp with
Hammond iron may not perform so well.

Impressive results explained! :-)
--

Stewart Pinkerton | Music is Art - Audio is Engineering