In article , Derrick Fawsitt
wrote:
I have just acquired Quad 989's Electrostatic Speakers and I find them
the ultimate and definitive solution, at least for me. I currently use
entirely Quad units to drive them, i.e. Quad 909 with its pre-amp
together with a Quad 99 CD Player.

I would tend to regard the current/recent Quad amps like the 909 as a
perfectly reasonable choice. Quad will probably have had this in mind...
:-)


However, I noticed one US reviewer of the speakers stated that while
the 909 Amp must have been designed with the Speakers in mind he found
that he got the best results with other amps, is this true and what
therefore do you consider the "best" setup to drive and to use with the
989s.

Well, FWIW I use an Armstrong 732 to drive my 988's and ESL63's.. :-)

However I doubt you will find one of the above, and I have reasons to be
biassed in favour of that amp. But I'd say it was 'the best' so far as I
was concerned - although I suspect that many other amps would do just as
well.

In general, I'd be inclined to take comments by magazine reviewers with a
pinch of salt.

As Serge has said, the peak voltage which are acceptable with the
988/989/63 is around 40/55 volts, so an amp that can give much more than
this should only be used with caution.

The speakers are less demanding as loads than something like the ESL57's.
They dip below 4 Ohms in the 10kHz region, and below 20Hz, though. Hence if
you were to be cautious and assume a 3 Ohm min and 55V peaks, it implies
you will want an amp that is happy to provide peak currents of over 18 Amps
to ensure no current limiting when playing music.

In practice, though, I'd expect/hope you don't normally get near these
limits.

My reaction in your position would be to use the 909's and enjoy the music.
Ignore reviewers. :-)

Slainte,

Jim

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