The other explanation is that the device you used for comparing the
frequency response and phase responses was not sufficiently resolving to see
the differences. I note you say almost identical so there was a difference
?
I note Stewart has pointed out that you cannot test without LMDBT. It is
most important that levels are exactly matched but I do not agree on the
merits of DBT. From memory Stewart has a Krell amp, if all "good" amps
sound the same does he think that it is not until you get to Krell territory
that amps sound "good" or was it their robust build quality that justified
the additional outlay ?
Regards Richard
"harrogate2" wrote in message
...
I must admit that I have never subscribed to the 'golden ear' brigade.
However I have used a Quad 33 as a pre-amp, later replaced with a
Cambridge C70 (A1 without the power amps) and now a NAD 3120 as a
pre-amp only.

I have to say that after getting used to the Quad, when I replaced it
with the Cambridge the sound was totally different - much more solid -
perhaps what some would describe as warmer - and with a noticable loss
of higher frequencies. The Quad by comparison would be described as
polite and laid back with a distinct lack of dynamics. Comparing their
outputs on a network analyser shows them to have a similar frequency
and phase response - certainly nothing that would account for the
audio difference.

The change to the NAD was more subtle but still noticable. Certainly
the top end was more detailed (cymbals and triangles show things up
remarkably well) and the bass was noticably deeper but not so 'in your
face' (I like classical organ music.) Again however the frequency
response and phase responses were almost identical to the other two.

Anyone any polite suggestions as to cause? Even my wife and children
(then teenagers) noticed the difference without asking or prompting.


--
Woody