• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

tube amp for ESL

One problem is that ESLs tend toward very low impedances as frequency rises - typically 2 ohms or less at say 20kHz. This can cause amplifiers with high output impedances (eg SETs) to roll off badly in the high end. My guess is you would need a powerful valve amp and/or one that uses feedback to do justice to most ESLs.

I have just about completed a valve amp design for Quad ESL 57. This is a SE design (for one of my friends) with no feedback and uses a transformer coupled output. The chassis should be available in 3 months time for me to assemble and test a prototype.

I think that there is some merit in considering a feedback amplifier for difficult loads such as ESL. But then again, the energy or power output required to handle frequencies above 10kHz would be very small.

Can anyone comment on the 40W? Atmasphere OTL's performance with Electrostatics.

In the mid seventies to early eighties, I designed a series of OTLs for use with my Magnepan MG IIB and I thought then and still think that OTL is the king of amplifiers. Of course Magnepan presented a simple load and the OTLs loved it.