Tube amp forethought

Three-easy, basically you are right but guys our age have a romantic passion for tubes. Who knows, maybe it is the smell of hot power tubes.
kgvteran, everybody is forgetting about our friend Mr Karsten. His amps (Atma-Sphere) are ideally suited for driving ESLs. I have been running ESLs of decades and his output transformerless tube amps are the only ones I would consider for the job. Actually, I am in conversation with him about having a pair made. He is even going to put a custom trigger in mine so I can turn them on remotely!  http://www.atma-sphere.com/Products/#M-60
These are the ones I would get for driving Quads.

If you don't mind the lack of a mono amp behind each speaker (thereby requiring only very short speaker cables---I used one-footers---though long inter-connects, one reason why it's great the M-60 is balanced, as long as your pre is as well), an S-30 (a stereo amp) is sufficient for a single pair of 57's. The speaker was made to be powered by the original QUAD tube amplifier, a 15w/ch design.

Roger Modjeski used the QUAD as his load when designing that amp.

We still use a Quad 57 in the shop today when we test amps we build or repair. If the 57s in question have the Zener clamp boards (an upgrade as they were not supplied at the factory with them) this prevents any over voltage condition within the panels and stops stator-to-stator arcing. So you will have more amplifier options at your disposal.

He has offered in in two versions: as a 35/35w Class-A/B, and as a 25/25w Class-A.

What might be one of the best kept secrets is the original RM-10s ran up to 15 watts in Class A and if you light load them you pretty nearly had a Class A amplifier.

I run my 57s with either the RM-10 or Atma-Sphere M-60s, but just picked up a Harvard H3 (Futterman) that Roger Modjeski and I will restore so it will be interesting to here this amp on the 57s when we are done.

Uh, is it just me? I don't see anything in particular about the ESL57 in the OP- just Quads.


So ESL63s or any later model like the 989 could be in the mix.


My experience with the Quads has been that you really have to watch it with the ESL57 because it really can't take much power. I've also seen updates that include protection circuits.


The ESL63 could take more power. We found that right about the point that our MA-1s were going to overload was also the point that the original protection circuit would energize. We also found that due to the way the amp interacted with the impedance curve, it could drive the ESL63s with greater volume than any other amp we tried.


The later Quads have been used with both our M-60s and MA-1s. Only the ESL57 has the low power limit issue.

Now if you are worried about the speaker no longer being made or that sort of thing, the ESL57 and 63 have a lot of support in the aftermarket- new diaphragms, power supplies and the like are available through various rebuilders. But you also have other alternatives like Sound Lab who arguably makes the state of the art in ESLs.

Ralph darn it. Don't complicate things. I'm trying to get him to buy your amps and you are spending all his money on Sound Lab's speakers.
kg, just in case you are interested the Quad equivalent Sound Lab would be the 545:)