If you want to use SS; find an amp with MOSFET outputs. They will maintain stability at low impedance levels. One can practically arc weld with some MOSFET amps. I used modded Hafler DH-500s with Acoustat Model IIIs(in the early '80's) with great success(was a dealer, back then). I much prefer tubes, but synergism with electrostatics is harder to reach. Here's a suggestion: (http://www.avahifi.com/root/equipment/amplifier/fetvalve_amps.htm) You don't mention your pre, but tubes would be nice there, and would give you the ability to tweak the system's presentation to suit your tastes.
What amp do I need to power my Acoustat 1100
I have had my 1100's for quite a few years. I stopped when the fried my (don't laugh, I was young!) carver tfm 35 amp. do you guys recommend a brand or price range I should be looking in. I have been looking into the krell amps I've seen for sale as well as the Parasound A21 but don't know whether that's bringin a Knife to a gunfight. Please give a novice some help.