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Quad ESL-63 and Yamaha A-S3000 compatible?

isapell

pfm Member
I have recently bought a pair of immaculate Quad ESL-63s to complement my Yamaha A-S3000 amplifier and have been extremely pleased with the results. However, I recently came upon the following quote of a comment by the Australian reviewer Greg Borrowman on using electrostatics with the A-S3000.

You will need to remember that because the output is balanced, the negative (–) speaker terminal is not at ground potential, so you should not try to connect the speaker terminals to anything other than a standard pair of speakers (that is, don’t connect the amplifier to electrostatic speakers or to a powered subwoofer).

I am now concerned that I am living on borrowed time (so to speak) and that the amplifier is likely to explode, shut down or damage the speakers. In the user's manual, much is made of the floating and balanced power amplifier technology, but the only warning Yamaha make is of connecting an active subwoofer to the speakers L/R CH terminal, as well as of various cross connections between the left and right terminals. Surely they would have written something if the Yamaha shouldn't be used with electrostatics?

If someone could help me out with this and (hopefully) put my mind at rest, I would be very grateful!
 
I was concerned about this too and therefore never tried my ESL 63s with my A-S3000 when I owned them. Instead, I used the A-S3000 as a preamp into a Quad 909 power amp. Even if the A-S3000's floating speaker outputs are compatible, I'd still be wary of using a Quad ESL into an expensive amp like this unless you know it can handle a dead short, because IIRC the ESL 63 has a 'crowbar' protection device against being overdriven. This saves the speakers but essentially destroys the amp's output if it isn't designed to cope with a short. Apparently Quad power amps are virtually indestructible when it comes to shorting the outputs.
 
If it was going to blow up it would have done so the moment you switched it on. There is no possibility of gradual damage here!
IIRC there were a few variants of earth wiring used on ESL63's and I vaguely recall @sq225917 (Si) looking into just this issue some time ago....
 
However, I recently came upon the following quote of a comment by the Australian reviewer Greg Borrowman on using electrostatics with the A-S3000.

I think he is confused, the manual states that the amp is balanced 'to just before the speaker output jacks'.
The manual also mentions, not connecting active subwoofers to the loudspeaker outputs, but no mention of ESL's. ESL's are only provided with power for the transformers.

You could check with Yamaha though.
I used to power my 989's with an AS 2000.
My current amps are fully balanced.

https://europe.yamaha.com/en/produc...omponents/a-s3000/downloads.html#product-tabs
 
If it was going to blow up it would have done so the moment you switched it on. There is no possibility of gradual damage here!
IIRC there were a few variants of earth wiring used on ESL63's and I vaguely recall @sq225917 (Si) looking into just this issue some time ago....

The early 63's had a 3 pin IEC connector and the transformers were earthed, later models have no such earth and a 2 pin IEC, as with my 989's.
 
Thanks for your comments - that's really helpful.

As my 63s are late models, I am assuming from them that I was fortunate that they presumably only have a 2 pin IEC and that if they had had a 3 pin IEC connector, they would have blown up?

It's also good to know that there is no possibility of gradual damage unless I overdrive them and the 'crowbar' protection is activated.
 
As my 63s are late models, I am assuming from them that I was fortunate that they presumably only have a 2 pin IEC and that if they had had a 3 pin IEC connector, they would have blown up?

I think neither is at risk, I think that Greg Borrowman, is confused. The internet is full of misinformation.

Having said that I would still check with Yamaha, as they may have some strange topology in their amplifiers.
As I recall they were very quick with their response, even they did contradict their own user manual.
 


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