Planar speaker that don't require herculean amp?

I'm looking for a planar electrostatic or ribbon speaker, but they all seem to require gobs of power. I am currently using AES Sixpac tube amps with KT66 tubes, which have about 35 RMS watts each or so. I don't have to worry about low bass, as I am using a pair of Entec powered subwoofers. I listen to many types of music, but don't need incredible high SPL levels. Are there any planar speakers out there (preferably used) that can work well with my tube amps?
Sound-Lab M1 and A1 will work with that amp in a reasonably sized room (not gigantic), provided 80 to 90 DB is sufficient max SPL. The need for power goes up on Sound-Lab as you increase volume and suffer insertion and compression losses.

Max volume with Sound-Lab is about 105 DB but requires 750 to 1200 watts per channel to maintain dynamics available at lower levels. Great sound at moderate levels were obtained in my room with Sound-Lab Ultimate 1's driven with a pair of Viva Aurora SET's that only produced 21 watts per channel.

Might be possible to squeeze more SPL with low power if the Sound-Lab is not required to do deep bass. It's certainly true bass requires more energy and Sound-Lab has rising impedance in the bass (about 30 ohms down deep). Making it difficult for transistor amps (and many tube amps) to produce enough juice.

Also, if the Entec subs crossover restricts low frequency in favor of the sub, the amps will have an easier time, although coherency will be damaged as the Sound-Lab is pretty much prefect in that area.
Thanks for responding. I've heard a lot about Sound Lab speakers, but they might be somewhat over my budget (3k or so max). The Entec subs have an internal low pass crossover at 100Hz. I'm currently using my surround processor which crosses over at 80Hz, although I'm considering the use of an outboard active crossover for greater control. I am currently using Montitor Audio GR60 speakers (which by the way are fine with the amps), but miss the planar magic (I used to have Martin Logan Quest electrostatic hybrids).
Actually, looking at Sound Labs website, model R-3 would probably be perfect, if I can get them for a lower price. They have a relatively high sensitivity, and are designed to work with a subwoofer. I also like that they have a wide horizontal dispersion.
We have a guy at the Apogee speaker users forum that (I think?) is using the sixpacks with his Caliper Signatures. I may be able to put you in touch with him.

I have Apogee Duetta Signatures and have just bought Rogue 120 monos to try on them...I don't have the amps yet so no report to give.

Apogee Stage should work quite well for you...not all Apogees are Scintillas.

I'm a Sound Lab dealer, and frankly the only Sound Labs that I think would work well with your amps are the hybrid Dynastats. They are definitely among the easier electrostats to drive even among hybrids, and show up used from time to time within your price range.

Quad electrostats are easier to drive than the big full-range Sound Labs are. Thirty-five watts would be still be marginal, unless you went for rebuilt ESL's (the originals, commonly called "57's"). They'd be within your price range, and they are absolutely lovely in the midrange but can be easily damaged by too much power (doesn't sound like you're into headbanger levels, though). Several people rebuild and/or offer rebuilt '57's; you might try inquiring for leads here:

Another possibility is Newform Research. I'm under the impression that their model 645 ribbon hybrid isn't such a beastly load. They have a loyal following.

Best of luck in your quest!

Thanks Dave for the suggestion on the Apogees. I did some research on them, and from what I read, they seem that they are a difficult load and require powerful amps. I would be interested to know how well that guy's sixpacs work with the Caliper Signatures. I am running a slighly less powerful configuration with my sixpacs with the KT66 tubes instead of the supplied EL34's. Let me know how your Rogue amps handle the Duettas.

- Stew
Thanks Duke for the response and email. That's too bad about the R-3's, but they're probably out of my price range anyhow. I'm not really interested in the Dynastats, as I am looking for a non-hybrid panel. I already have the Entec subwoofers, so don't need to worry about anything below 80Hz.

The Quad ESL-57 is a very interesting suggestion. This speaker certainly seems to have a loyal following! I am a little worried about SPL levels however. It appears I listen at levels that are a little higher than I thought. I did a few SPL measurements with my RS meter, which were showing values of up to 97db or so at 1 meter. This was a level that would be about the maximum that I would need. Can the ESL-57 (cut off below 80Hz) handle this SPL? Would stacking the panels, as I've read seems to be a popular option, be able to handle higher SPL's?

- Stew

Here is a link to a post our forum member (jaragaki) made regarding his new sixpacks and Calipers.

I'm sure that you could also email him with any questions you may have.

Thanks Dave... I'll take a look.
Duke you really need to stop mentioning your products in every post even though you are not recommending them. Can't you see the problem? Communicate them in private emails.

Again from the Apogee website, Graz (Master of all things Ribbon) has a new launch ready.

His new full range ribbon can be driven by low power valve!
Are you set on a full range electrostatic? If not, consider used Innersound Eros. This is an 'stat panel mated to a transmission line bass section which is driven by an integrated amp/crossover unit. The panel itself is quite efficient and the speaker can be driven to astonishing levels (if so desired). The only caveat is that your amp must be stable into a difficult impedance load. I would expect that your Carys would be just fine.

One further comment on the possibility of the Quads. Given your listening preferences, there is no way in the world that these will satisfy. There were - and are - great speakers for certain things, but high SPLs? No way.