What kind of power wakes up electrostatic speakers

Sean, which Acoustat?? All of the Acoustats that used the 121 type interface - that included the II,III, IV, VI, VIIs
absolutely do NOT have any impedance dip below 6 ohms. I am not convinced that any did, unless they stopped using Jim Strickland's patented "bi-former" interfaces with the last of the breed - the hybrid Spectra series stuff.

This is the published data for those speakers. My own tests confirm this. Indeed it is the basis for the patent.

As far as the Acoustats "sucking" amps dry is more due to the large voltage swings required for peak output, and deficits in those amplifiers' design. Since ESLs tend to have lower distortion than many cone speakers, the onset of
"distress" is easily heard.

On the other hand, I know at least one person with a very nicely done 35 watt tube amp that drove them with no trouble at all.

Quite a lot of people ran them with receivers too - as long
as you didn't stress the amp (play too loudly) they sounded pretty much ok.

So, I'm not sure what sorts of problems you've encountered with Acoustats - again if it is the later "Spectra" series, all bets are off, as I have no idea what they ended up doing towards the end of the product's life.

I owned Acoustat IVs for many years. Anyone interested in electrostats should visit this site:

http://www.audiocircuit.com/

It contains all the original information on virtually every electrostat ever made. It includes a copy of the original paper "The technology of full-range-element electrostatic loudspeakers" by James Strickland, President of Acoustat Corporation.

This paper includes a discussion of the interface and amp requirements. It also shows the impedance curve for the Acoustats which dips to 3 ohms.

I'm very happy with my Mcintosh MA-6500. It sounds great, has more than enough power, and great features. The MA-6900 is another good one to consider.

Bear, i'll see if i can dig up the info on that specific Acoustat. As to running Acoustat's with receiver's, we've all seen systems that worked but were far from optimized. In fact, i think that most of us still own them : )

Pls1, while i haven't had a chance to look at the Strickland paper that you mentioned, i have seen that website. It is a wealth of information for fans of E-stat's. Sean
>

Bear and Sean, the paper I referenced on that website shows the impedance curve for the specific MK 121 interface as well as the details of its implementation. The impedance is below 6 ohms except for the frequency band between 500 and 4000 Hz.