MartinLogans and Cary CAD-805s / electrostats and SET amps

chattaudio

I had some I built that were based on the Wavac 805’s even better than the Cary with my ML’s. Even if bi-amp’d and just driving the ML’s esl panels with the 805’s, you’ll get a severe roll off in the highs. All ML esl panels go down below 1ohm!! in the HF, and have nasty -60 degree phase angle and 3ohms at 4.5khz, and tubes just don’t cope with it and act like a tone control.

Stereophile on the Montis
A figure of 0.55 ohm at 20kHz. Either way, that this speaker is a difficult load for the partnering amplifier to drive is compounded by the high electrical phase angle
https://www.stereophile.com/images/912Montisfig1.jpg

Put a good high current high biased Class-A/B on the Montis like a used Parasound Halo A21 or new A21+ if you have the money. You could if you want to be tight with money, even try a used Halo A23 on the panels.

https://parasound.com/a21.php
https://parasound.com/a21+.php
https://parasound.com/a23.php

Cheers George

@georgehifi Thanks, George!  So basically, I am looking for a high-current SS amp to drive MLs, more or less the opposite of SET, correct?

Yes, unless you want it to act like a tone control and give colorations.
Cheers George

A tube amp that works well with Martin Logan speakers is the Music Reference RM-200. It was designed to handle loads down to 1 ohm.

As clio metioned there is that tube amp the RM200 MkII from Roger (rip), which has down to 1ohm speaker taps the only trouble is as you go down in "ohmic taps" so does the output wattage.
The 2ohm may be fine to drive the ESL panels, but you "may not" get the wattage needed for loud'ish level's. (try before buying)
And sadly the HF frequency response takes a bit of a nose dive from the 2ohm tap https://www.stereophile.com/images/1211RM2fig01.jpg

Cheers George

Sorry didn't mention, the 2ohm tap is the bottom dashed line
https://www.stereophile.com/images/1211RM2fig01.jpg

Cheers George

Alternatively you can use a set of ZEROs (www.zeroimpedance.com) which will allow you to use a tube amplifier and the highs will be just fine.

The high frequencies do not need a lot of power. but the overall sensitivity of this speaker is low enough that I would certainly question the use of the Cary- even with the ZEROs it might not be enough power!