What amp do I need to power my Acoustat 1100

Any amp stable at one. ohm. These are not easy to rive becauze they do present 1 ohm laods but employ fonick transforms thst friend's melted with an Aragon m0n0 block palladium 1Ks.
Instead try a favorite for low ohm loads the ICE powered H2O brand.

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i wanna spend $2500 or below.

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.

If you want a great stereo (actually 'dual mono') SS amp for around $2500+ look for a Mark Levinson 23.5 (not a 23, a 23.5!) 200W @ 8 ohms, and worked beautifully into 0.7 ohms! of my MartinLogan CLS's.

If on the other hand you want a great tube amp which puts out a very "current rich" 90W/ch you can't go wrong with a McIntosh MC275 Mk IV or Mk V; which are now selling used within your budget.

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.

I think this has become a popular misconception. If you want to roll tubes to tailor the sound of your system, you need a tube amplifier. In a preamp (with the exception of a PHONO preamp), the tubes aren't used for amplification, and therefore have little effect on sonics other than adding a certain amount of tube hiss to the signal (even in the more expensive units.)
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Ns said, "I think this has become a popular misconception. If you want to roll tubes to tailor the sound of your system, you need a tube amplifier. In a preamp (with the exception of a PHONO preamp), the tubes aren't used for amplification, and therefore have little effect on sonics other than adding a certain amount of tube hiss to the signal (even in the more expensive units.)" In my experience, I've found tube rolling worked wonders in quite a few pre-amps over the years(especially my own ARCs), and particularly in units with tubed power supplies. Voltage gain is the purpose of most tubes in a pre-amp(just as in a phono stage), and they are in the signal path. Any tubes used in a pre-amp(or phono stage) need to be screened and certified very low-noise, regardless of the unit's cost.
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