Acoustat Electrostatic spearkers

In the early 90s I had 2 + 2s with both the interfaces and OTL tube amps, I much preferred the OTLs, and although they sounded much better than the interfaces, the amps weren't very stable. I witnessed many cherry glowing tubes. I sold them, it wasn't until much later that a few guys figured out how to make the OTLs stable

Not sure what you're asking... Love my Spectra IIs.

If you're on Facebook, I suggest you ask questions on the Acoustat page. There are some serious subject matter experts there.
https://www.facebook.com/groups/167493963322951

Hooked up an Audio Research D200 (years ago); smoked the amp and Acoustats in the first 5 seconds. 

schweibnsk
Acoustat Electrostatic speakers

I had 2+2's for a long time, then had a chance to purchase a pair of 2's cheap. which I built a frame for and converted into 1+1's.
These 1+1's were the best imagining and depth speakers I have ever owned.
 I crossed them over actively with 4th order 24db at 100hz to a pair of very rare Kef B1814's with had an FS of 19hz, in 11 cubic foot, ported enclosures that Neville Thiele nutted out the box design/port for me.

Cheers George

I sold them, it wasn't until much later that a few guys figured out how to make the OTLs stable

Uh yeah- that would be me... FWIW (one of Atma-Sphere's claim to fame was the first reliable OTL).


Sure- just don't exceed the phase margin of the amplifier when you design the feedback loop (this is really all that was about, and it really shouldn't have been me that solved this, as its standard control theory which has been around for a very long time, and this rule applies to any tube amp or traditional transistor amp!). That was the Achilles heel of many OTLs. The designer(s) tried to get greedy in an effort to send the output impedance down, but the price for that wasn't worthwhile. However, OTLs don't need feedback to drive the Acoustats quite nicely! A good friend Frank (RIP) had a set and I heard them many times.