Any of my existing amps work on Quad ESL-57's

Hi All,

I just purchased a pair of ESL-57's and will be keeping my eyes open or suitable amps. I'm not sure whether what I have in house are suitable.

Currently working, I've got a super high power solid state Classe Omega and a 300b SET amp made by Quicksilver Audio. For the Omegas, besides the impedence mismatch that hampers some solid state amps, do I need to be worried about too much power? If I'm careful not to blast them, should these be OK? Per the 300b's - is this too little power? Risk of clipping? The room is 14x18x11high.

I have a pair of EL34 amps: Cary SL70's - but they need some tuning up. Seems like they could be a good match. I may send these to Cary for tuneup. Any thoughts?

Finally, I have a CAT SL2, but I want to replace the fuse resistors in it prior to using it. It's an older production model, and the newer fuse resistors are safer.

If neither of my currently working amps are recommended, I may purchase an inexpensive amp to keep me going. A Rogue Atlas Magnum, a rebuilt ST-70, maybe look around for Heathkit UA-1's or other not too expensive solutions.

Good advice appreciated. Thanks, Peter
Tune the Cary's. Try your others in the meantime and just use caution. Good luck.
Look for McIntosh MC30s.Magical with RCA 1614s and 8 ohm output tap for 15 watts.I have heard dozens or more amps with 57s.
The Quads are unusual in that they require a surprising amount of power to sound their best but that tweeter panel can be damaged quite easily. The solution: Get the protective 'clamp' circuit installed on the tweeters and then you can use any amp you want without fear of damage to the 57s.

I used a Rogue Atlas Magnum on my 57s and it was a superb match. The Atlas was a significant improvement on the ST70 and the UA-1 (rebuilt by Mapleshade). I have not heard the Cary model you mention but it might be interesting to try.

I tried a 300B SET amp with my Quads (KR Enterprise 18 BSI) and did not like the result very much. The midrange was very nice but the top end and bass were significantly rolled off. Dynamics also suffered considerably.

A powerful solid state amplifier like the Classe would be very interesting and it would not suprise me if you found this to be the best of the lot. But get that clamp board installed to protect those tweeters first.


I was introduced to Quad 57s in the 90s and listened to quite a few other enthusiasts setups.
The best set up I heard was with either the Quads tube amps or Luxman equivalent to the quads. I had the Quads on the 15 ohm tap. This is a matched system. It was very immediate and detailed. All the other Tube amps created smaller dynamic swings and put you more in the back row of the concert hall. I preferred to be nearer the front row. This was to my taste but is not ever ones cup of tea.
Too little power from a tube amp will just sound poor when over taxed. It should not damage the panels.
A tale of caution about too much power.
My wife left the quads on for a week when I went on a business trip, burning out the Quads tubes. I used an Audiolab transistor amp (60 watts per channel) while I waited for new tubes. My wife turned the Audiolab amp up and telephoned me at work to say that the 57s sounded distorted - She blow up the treble panels on Both. So if you use a more powerful amp then be very careful that you turn them down when they distort (you should already have the 57s snubber circuit mode installed if they are latter Quads 57s - this is a diode and a resistor network that kick in when the panels see too much voltage and protects the panels hence you hear the distortion and turn them down. If you do not turn them down in a reasonable time then the diode will burn out leaving the panels unprotected to voltage spikes.
hope this helps
Russell b
Terry is right on the money - Snubber circuit is the clamp module.
Russell and Terry - thanks for you good input. I've read that the Rogue is a good match, so I'll wait until one shows up. The speakers do have the snubbers installed on them. In fact, the previous owner did push them too hard and stressed the diodes on one snubber, causing distortion in that speaker. He got a replacement snubber from WP and all was restored to normal.

It sounds like as long as I'm careful, I will be fine with what I have. The Cary may be an excellent fit too.

Best, Peter
I've had plenty of 57's including stacked. Best amp was the 8417 Quicksilvers.
Do NOT use high powered transistor amps - you are asking for trouble.
For solid state the old Electrocompaniet 25 watts pure class A was excellent.
So I would recommend any medium powered valve amp around 60 watts. Of what you have the Carey sounds most promising. I would try and pick up a pair of EL34 based Quicksilvers.
If you lift them off the floor ( I used small tables about 14" high ) and tilt the speakers so they are more upright, the imaging and bottom end improves significantly.
"Do NOT use high powered transistor amps - you are asking for trouble."

The ASR Emitter is known as an excellent match for PK-restored 57s. (With, of course, the clamp boards.) Considered the very best match by some gentlemen out east who have spent months or years auditioning dozens of amps of all types on them.

Of course, this is a matter of taste as always.

The Emitter is indeed a great match, but I have found that OTL tubes in the 20-30 watt range are also superb and really do give all the speaker is capable of in terms of dynamics. Which is actually quite a lot - the PK-restored Quads being around 90 dB/W. There is a Graaf GM20 for sale here now - unfortunately from Asia, though, so risky shipping perhaps. That is a fine amplifier.

Tranformer-couple tube amps of course can be great as well and most people do find 20-40 watts to be enough power (in a high-quality amp with stiff PS, anyway). But, OTL architecture seems to be tailor-made for the Quads' rather peculiar impedance.