tube amps and electrostatics

Probably why Quad, aka- Peter J. Walker(RIP) & 'The Acoustical Manufacturing Company', has been building a line of tube amps, for so many decades.

Sure(the 303 being the first)- But not until 11 years after Walker demonstrated his first truly full-range electrostatic speaker(in 1956). Around the same time that everyone else(McIntosh, ARC, et al) was bowing to SS and the output power demon.

Mr G- You may want to realign your blanket statement, re:
MOS-FETs
and
current. MOS-FETs are innately self-protecting, regarding
thermal
runaway, unlike bi-polar transistors
(http://www.onsemi.com/pub_link/Collateral/AND8199-D.PDF).
I sold(mostly modded)
David
Hafler products, for years, which all used MOS-FETs as
output
devices. As a sales point: I used to demo the DH-500,
measuring the amperage into a 2 ohm dummy load. I had read
as
high as 48 amps, without damage or overheating(and thermal
protection activation). You could practically arc weld with
the suckers! I, as well as a couple other customers, owned
Acoustat Model III's, and had excellent results with the
Hafler amps, at realistic SPLs.

MR G- I can't recall ever seeing anyone publish specs,
claiming to double output wattage, all the way to two ohms.
Nor did I claim that for the amps that I sold. re: Current
handling/MOS-FETs
vs BJTs: Maybe that first article wasn't clear enough, or too
technical. Here's something a bit easier to digest, perhaps:
(http://www.ixys.com/Documents/AppNotes/IXAN0061.pdf)

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!

Ralph- Save your keystrokes.