In message , Serge Auckland
writes
My inclination would be to stick with the Quad amplifier.

Firstly, it will have presumably been designed and tested to work with the
989 'speakers, (as well as being able to drive other loads).
The 989 'speakers will have been designed with a view of being driven by the
909, although of course other power amps could be used.

Then there is the specification of the 989 to consider: The maximum
programme input to the 989 is 40v. The permitted maximum is 55v. Now, the
909 is rated at 140 W rms into 8 ohms, thus generating 33v rms or 47 v peak.
It seems to me that therefore the 909provides the optimum power output for
the 989 'speakers. Any more power, and you would exceed the maximum ratings,
any less power, and you would be losing some potential peak loudness
capability.

But I think the main reason for not changing is that what improvement can
you expect? When the 909 already provides optimum power, vanishing low
distortion and noise, what possible audible improvement will you get?

S.

Thank you so much Serge, I am non technical but have printed out your
above reply for reference in the future.

One recent incident might interest you, before I acquired the 909's I
was considering buying a pair of second-hand 63's but on trying them
they appeared faulty as they produced distortion and in one case cut
out. They needed my 909 to run at its maximum level, (34), in order to
try to achieve a reasonable volume causing it to run extremely hot.
Needless to say I returned them to the dealer who sent them to Quad for
testing and servicing. I had a witness to their lacklustre performance,
a friend who has a pair of 63's for many years and knows his way around
Quad speakers. He confirmed the distortion etc., and it is therefore so
astonishing to hear today that Quad said they were perfect and is
charging the dealer £150.00 for testing them. I feel embarrassed in that
I said they were faulty, (which they definitely were and my
knowledgeable friend verified this), yet Quad now say there is nothing
wrong with them, how can this be?

Now I find the 909's an absolute revelation.

Thank you again Serge and also all who have helped to date.
--
Derrick Fawsitt