Advice using electrostats with tube amp.

I'm guessing you have an issue with high frequencies. If that's correct, I think the ML's are a pretty good choice. Personally, I find the main reason I'm drawn to an esl speaker is that they don't have a tweeter. The highs are much more realistic and natural sounding.

Jim (Broadstone), an impedance curve for the Ethos can be found on this page. My guess is that given the relatively small amount of energy that most music has in the top octave the 0.8 ohm impedance at the upper end of the spectrum won’t **in itself** be a problem, provided that you use the 4 ohm tap on the amp. And, as you mentioned, operating the amp in ultra-linear mode might turn out to be preferable.

However, I suspect that what stands a greater chance of being an issue is the effects on tonality of the interaction between the amp’s output impedance (which will differ between triode mode and ultra-linear mode), and the wide variation in the impedance of the speaker, within the range that is handled by the panels. Specifically, if you see this post prior to today’s audition I would suggest looking for signs of over-emphasis of the mid-range (where the impedance rises to around 18 ohms at 1 kHz), relative to the treble region (where as you realize the impedance gradually descends to very low values).

That interaction, btw, will vary widely among different tube amps, due to the widely differing output impedances among different tube amps. And given also that the output impedance of the 88R does not appear to be specified, nor does its damping factor from which output impedance can be calculated, it’s particularly good that you have an opportunity to audition the specific amp/speaker combo.

Best regards,
-- Al

Thanks, Al. I was hoping you'd see this post. As always you provided exactly the kind of direction that I needed. I wasn't specifically looking for the potential of generally over emphasized mids, but I did detect a hint of that in the lower mid frequencies that you suggested and that I had also experienced with the Odysseys using Rogue and Peachtree  solid state amplification. This issue is not significant enough to affect my decision to buy them back and I did just that. Not just from a budget standpoint was this a very hard decision but stepping away from the Reference 3A's is particularly distressing. I hope i can get a reasonable offer for these amazing speakers. I did the audition using the 4 ohm posts and tried it on ultralinear as well as triode settings. As with the Serie's i found the triode mode somewhat more pleasing.

BTW, because i have a loaner pair of Cary made AES SET2 monoblocks currently set up I tried them with the ML's also. Theyre ok but the Cary is a bit warmer sounding to me.  Thanks once again, Al.       Jim

Sounds good, Jim.  Enjoy!

Best regards,
-- Al
 

Atually, the "warmth" that I heard and generally favor with the triode mode
was a bit too warm approaching somewhat dull. I switched to ultralinear for overall improved upper mid detail. Just an FYI.