I don't post much here anymore but
sometimes follow a thread or two. This one piqued my interest because it
mentioned a couple of my favorite amps. It also piqued my interest because I think there are a few points by other posters that should be reinforced.
First, I have experience with SET amps having worked with someone for several years well known for manufacturing transformers and designing several SET amp circuits for our own manufacturing and sales. I can say from his perspective, the designs were best put to use on speakers whose efficiency was 98 dB or higher. However, we found one interesting exception to that rule. Pairing a 12 watt 300B with a pair of Fritz Carbon 7 speakers (88 dB, 6 ohm) at a very popular audio show. That matching came about by accident, as a 50 watt PP amp failed on us and while it was being repaired we played around with the 300B. We didn't go back. Anyone who heard that combination was amazed it could work. We played it as loud as we could and it continued to perform flawlessly. Sometimes you get lucky, but as Ralph pointed out, the norm will have different results.
The M-60 OTLs will drive your speakers quite well. I have used them for several
years now with a variety of speakers ranging from 88 dB to 94 dB, with both
smooth and somewhat bumpy impedance curves. In fact I used them with
AudioKinesis Jazz Modules for a majority of that time and now with Quad ESL 57,
using autoformers to better match the impedance. The autoformers add nothing to
the sound in my opinion.
Bill's (grannyring) suggestion of the Music Reference RM-10 is spot on. This amp has balls and puts out 35 watts per channel (double what most EL-84 designs can muster). I have owned mine for
12 years now and used it on many speakers. It just recently powered speakers I
am playing around with that go down to a 2 ohm load in the 15 - 20k range. No problem
whatsoever. It works great on the ESL-57s as well.
One thing I've learned over the years is there are other factors that can determine how an amp matches up with speakers. I believe Ralph mentioned the size of the listening room and how loud you like to listen. Another is damping factor, or the amps ability to control the woofer. Lately a question I've been asking speaker manufacturers is what amps did you use to test your speakers. Generally that will give you a good idea of the damping requirements. Some speakers were designed with solid state in mind, others tube amps. You can learn a lot talking to the speaker designer.
I suppose you should take what I say with a grain of salt:
1. Jack Elliano is my business partner.
2. I am an Atma-Sphere dealer.
3. I work with Roger Modjeski
