Best Amps to use with Quad 989 Speakers
 

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. 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.
--
Derrick Fawsitt

Best Amps to use with Quad 989 Speakers
 

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.



"Derrick Fawsitt" wrote in message
...
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. 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.
--
Derrick Fawsitt

Best Amps to use with Quad 989 Speakers
 

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. 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.

They are designed for the Quad II-forties and QC 24 pre amplifier

Best Amps to use with Quad 989 Speakers
 

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

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

Best Amps to use with Quad 989 Speakers
 

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

Best Amps to use with Quad 989 Speakers
 

Derrick,
I'm glad you found my comments helpful. That's the beauty of these
newsgroups!

Regarding the ELS63, from what you say, it sounds as if something wasn't
right, however a few things come to mind:-

1) From your description, it isn't clear if the problem affected one or both
'speakers, and if the 'fault' was the same on both. As the 'speakers are
completely separate units, it is unlikely (but certainly possible) for both
to go wrong in the same way at the same time. In my experience, albeit not
as an ELS owner, the '63s do require service from time to time. A close
friend with a pair has had several panels replaced over the past 10 or so
years, and he certainly doesn't abuse his 'speakers. His amp is the QUAD
306.

2) The ELS63 has a "crowbar" protection system. This means that if the
'speakers are being seriously overloaded or the mains isn't on, then the
'speakers present essentially an intermittent short-circuit to the amp. This
will certainly sound horrible, and if persisted with, will cause the amp to
run hot, shut down or blow up depending on how well designed it is. If that
is what happened in your case, it shows how well engineered the 909 is that
it just got hot. The term "crowbar" protection is a fanciful term used to
describe the sort of protection that puts a quick-acting short-circuit
directly across the circuit being protected, thus limiting any damage. It's
as if you put a crowbar across the line.

What surprises me, and I don't really have an explanation, is why QUAD's
service department couldn't find anything wrong with the 'speakers if they
were as you described. One of life's mysteries!

S.


"Derrick Fawsitt" wrote in message
...
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

Best Amps to use with Quad 989 Speakers
 

In article , Serge Auckland
wrote:
Derrick, I'm glad you found my comments helpful. That's the beauty of
these newsgroups!

Regarding the ELS63, from what you say, it sounds as if something wasn't
right,

I would agree. It did seem to me that the 909 was being asked to supply
high currents and perhaps this was due to the ESL63 protection coming inot
play when it should not.

however a few things come to mind:-

1) From your description, it isn't clear if the problem affected one or
both 'speakers, and if the 'fault' was the same on both. As the
'speakers are completely separate units, it is unlikely (but certainly
possible) for both to go wrong in the same way at the same time. In my
experience, albeit not as an ELS owner, the '63s do require service
from time to time. A close friend with a pair has had several panels
replaced over the past 10 or so years, and he certainly doesn't abuse
his 'speakers. His amp is the QUAD 306.

FWIW though, I've had a pair of ESL63s since 1984. In that time they have
not required any service, and still sound fine. They have been used with a
power amp capable of over +/-80v peak and over +/-30a peak. However I have
used them with care, and most of the time at quite low levels. My
experience therefore is that if used with care they can last a long time.

2) The ELS63 has a "crowbar" protection system. This means that if the
'speakers are being seriously overloaded or the mains isn't on, then the
'speakers present essentially an intermittent short-circuit to the amp.
This will certainly sound horrible, and if persisted with, will cause
the amp to run hot, shut down or blow up depending on how well designed
it is. If that is what happened in your case, it shows how well
engineered the 909 is that it just got hot.

For obvious reasons, Quad design their amps with current limiters so as to
be able to endure working into the 63 crowbar for extended periods. However
other designers do not always do this, and may have good reasons for
avoiding using current limiters. So this is a point worth bearing in mind
if considering a non-Quad amp.

The above should not matter if used with care, though. FWIW The amp I use
would have evaporated the crowbar device in the original ESL64's as the
current rating of the triac was well below what the amp will sustain. Yet I
have never had a problem as I simply use the speakers well within their
design limits.

What surprises me, and I don't really have an explanation, is why QUAD's
service department couldn't find anything wrong with the 'speakers if
they were as you described. One of life's mysteries!

I have been wondering about two possibilities, but they both seem 'long
shots'...

1) That when Derrick was using the 909 + ESL63's there was some 'RF' for
some reason and this was triggering the protection.

2) That for some reason the speakers were not getting the mains power to
polarise properly. This would reduce sensitivity and prompt the owner to
turn up the volume, thus leading to problems.

However apart from the above, dubious, guesses, I also find this strange.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

Best Amps to use with Quad 989 Speakers
 

In article , Dave
xxxx wrote:
Derrick Fawsitt wrote:
I have just acquired Quad 989's Electrostatic Speakers

[snip]

They are designed for the Quad II-forties and QC 24 pre amplifier

I am not sure that was the case. Although the combination might sound fine
I'd note a few points:

1) The II-40 has a nominal power of 40wpc. This nominally translates into
17.8 Vrms and 25 Vpk for an assumed 8 Ohm tap. This is well below the
maximum which the 989 can accept. This means the combination will be
'safe', but not be able to reach the same peak sound levels as a more
powerful amp.

2) The II-40 has an output impedance of 0.4 Ohms. Given that the 989 has an
impedance that drops to just below 4 Ohms at some frequencies this may
cause a change in the response of the order of 1dB in the region around
10kHz and below 30Hz.

3) I don't have a value for the peak currents the II-40 can provide.
However unless it is significantly higher than implied by (1) the actual
levels may be further restricted when the signals have components in the
regions where the impedance of the 989 dips down well below 8 Ohms.

Hence although the combination may sound fine, the above factors can be
expected to have some impact on the results. If you only ever play music at
low levels, the above may not matter.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

Best Amps to use with Quad 989 Speakers
 

In article , Serge Auckland
writes
Derrick,
I'm glad you found my comments helpful. That's the beauty of these
newsgroups!

Regarding the ELS63, from what you say, it sounds as if something wasn't
right, however a few things come to mind:-

1) From your description, it isn't clear if the problem affected one or both
'speakers, and if the 'fault' was the same on both. As the 'speakers are
completely separate units, it is unlikely (but certainly possible) for both
to go wrong in the same way at the same time. In my experience, albeit not
as an ELS owner, the '63s do require service from time to time. A close
friend with a pair has had several panels replaced over the past 10 or so
years, and he certainly doesn't abuse his 'speakers. His amp is the QUAD
306.

2) The ELS63 has a "crowbar" protection system. This means that if the
'speakers are being seriously overloaded or the mains isn't on, then the
'speakers present essentially an intermittent short-circuit to the amp. This
will certainly sound horrible, and if persisted with, will cause the amp to
run hot, shut down or blow up depending on how well designed it is. If that
is what happened in your case, it shows how well engineered the 909 is that
it just got hot. The term "crowbar" protection is a fanciful term used to
describe the sort of protection that puts a quick-acting short-circuit
directly across the circuit being protected, thus limiting any damage. It's
as if you put a crowbar across the line.

What surprises me, and I don't really have an explanation, is why QUAD's
service department couldn't find anything wrong with the 'speakers if they
were as you described. One of life's mysteries!

Yes very much so. Wonder if you've been told the total truth here?,
something doesn't add up!.

I've used me 63's for years with an Audiolab 8000 power amp with no
problems at all, apart from an absolutely boring old sound coming from
them;))
--
Tony Sayer

Best Amps to use with Quad 989 Speakers
 

On Fri, 06 Jan 2006 09:39:54 +0000 (GMT), Jim Lesurf
wrote:

In article , Dave
xxxx wrote:
Derrick Fawsitt wrote:
I have just acquired Quad 989's Electrostatic Speakers

[snip]

They are designed for the Quad II-forties and QC 24 pre amplifier

Absolute garbage! That combination is nowhere near capable of
extracting everything that the 989 is capable of delivering -
especially as it's valved.......................

I am not sure that was the case. Although the combination might sound fine
I'd note a few points:

1) The II-40 has a nominal power of 40wpc. This nominally translates into
17.8 Vrms and 25 Vpk for an assumed 8 Ohm tap. This is well below the
maximum which the 989 can accept. This means the combination will be
'safe', but not be able to reach the same peak sound levels as a more
powerful amp.

Quite so - and one of the basic tenets of the 989 is that it has
significantly more dynamic range than the '63.

2) The II-40 has an output impedance of 0.4 Ohms. Given that the 989 has an
impedance that drops to just below 4 Ohms at some frequencies this may
cause a change in the response of the order of 1dB in the region around
10kHz and below 30Hz.

Indeed so - although to be fair, I doubt that this will be of audible
significance for most listeners in most rooms. Still, it *is* a flaw
in a supposedly high-fidelity system, from one of the premium
engineering-led brands.

3) I don't have a value for the peak currents the II-40 can provide.
However unless it is significantly higher than implied by (1) the actual
levels may be further restricted when the signals have components in the
regions where the impedance of the 989 dips down well below 8 Ohms.

Indeed, current delivery is the Achilles heel of almost all valve
amps.

Hence although the combination may sound fine, the above factors can be
expected to have some impact on the results. If you only ever play music at
low levels, the above may not matter.

But you'll still get better results from any half-decent 60-watt SS
amplifier, of which there are dozens of excellent examples around, for
a fraction of the cost of the nostalgia-driven II-40.
--

Stewart Pinkerton | Music is Art - Audio is Engineering