tube amps and electrostatics

I am no fan of SS amps(except for driving woofers), but-
when someone makes blanket
statements, regarding MOS-FETs and ESLs; I have to take
exception.
Whatever their application; they still protect themselves
against thermal runaway, unlike BJTs, and can remain stable
in high-current situations. I
will side with those that have used them(past and present),
to great success,
in
their output circuits, ie: David Hafler's SS amps, Acoustat
TransNova TNT 200,
Van Alstine Synergy 450, Accuphase A-60, BAT VK-655SE,
Goldmund Mimesis8, Jeff Rowland M-9, to name a few(all Class
A or A/B). I've
not
heard any of those accused of being unstable, into any kind
of
real-world load. It's been my experience, as well as
others,
that MOS-FETs(in a correctly designed circuit) have no
problems driving ESLs. You mentioned PASS and I'll use the
following article, as my parting shot. Especially pay
attention to the portion entitled, 'Stretching Those
Muscles':
(http://dagogo.com/pass-labs-x350-5-amplifier-review)
Happy listening!

Rodman999999 You mis-read my statement on I vs R.
I said "that can almost double", the app word being "almost" you read what you wanted to see.
And here is the advertised specs of an Australian amp called and ME1500 and yes it can "almost" double all the way down to 1ohm 220-8 430-4 800-2 1500-1. And thats both channels driven at the same time!!

http://www.me-au.com/ME_1500_data_1.jpg

http://www.me-au.com/ME_1500_data_2.jpg

And even the smaller ME amps do the same amount of "almost" doubling. Show any Mosfet that can do these kind of figures, and like I said I'll show you a case for false advertising.

Cheers George

Regardless, the ability of an amp to double power as impedance is cut in half is not an advantage on an ESL. This is because the speaker really wants to see constant power regardless of its impedance at a particular frequency, as the impedance curve is based on a capacitor rather than the resonance of a driver in a box.

Consequently tube amps have been the preferred choice for ESLs since the 1950s and remains that way today- if you really want to hear what the ESL does, you gotta have tubes, else you are leaving a lot of the speaker's capabilities on the table.

I couldn't agree more. I base that strictly on what my ears tell me whenever
I hear electrostatics. What I hear is that the transparency of electrostats
lays bare ss amps' tendency to sound leaner and less dimensional than
tube amps with a resulting sound that can can be sterile and dimensionally
flat; as opposed to the dimensionality and image density that a good tube
amp offers. A couple of examples of this (besides my own) that come to
mind are Martin Logans run by Threshold amps at audio shows,
Quads/Spectral at Lyric, and most recently a friend's InnerSounds with the
InnerSound amplifier. On the very same InnerSounds, my Manley tube
monos sound timbrally closer to real with full and and dimensional images;
but, admittedly, not capable of as much volume or bass extension. In
fairness, original Quads driven by Levinson ML2 sounded very good.

Frogman: "original Quads driven by Levinson ML2 sounded very good."

And what you would have also heard was a more defined and extended treble because those quads and these (ML's Acustats and other els's) go below 1ohm in the treble and start that impedance dip at 10khz.
Tubes I aggree with these speakers still sound good but they are definately subdued in the treble compared to a GOOD s/s amp that is BJT output and that can do current into low impedances. Like you found with the ML2 which can almost keep doubling it's current down to 1ohm for each halving of impedance.

Cheers George