The Absolute Sound, August 2000, Harry Pearson, reviewer

Editor's Choice:  Mid-Year Edition

I'm not about to steal my own thunder here, I hope, by letting you in on a secret.  InnerSound's new solid-state amplifier, designed specifically to drive the weird loads posed by electrostatic speakers, brings out a degree of performance - and loudness - I never expected to get from the Quads.  With the assistance of a Carver subwoofer (rolled off above 40 Hz), I managed to play the entirety of the soundtrack from "Gladiator" without so much as a blown fuse and, in Music Room 2, with enough volume to replicate the movie's dramatic effect.  Not only did I get greater dynamic range from the speaker, but seemingly wider frequency response as well.  

Sans woofer, the Quads went deeper into the bass (they held up into the 40 Hz region) than I'd heard.  And at the other end of the spectrum, they reached higher more comfortably.  I believe in an ordinary (no, not large) room, like No. 2, I could, with the exception of certain Telarc Kunzel potboilers, play almost any composition of musical interest at something approaching a concert-hall dynamic range, especially with the Carver sub thrown in for reinforcement of the bottom octave (below 40 Hz).

Given the peculiar nature of an electrostatic load, sez the well-written explanation (for a look-see, check out the website, such an amp must produce not only voltage, but prodigious amounts of current as well.  And check out the claim that the InnerSound "can deliver a staggering 135 amps of current with a combined power rating of 4500 watts per channel."  And "it can drive loads below one ohm without damaging its output transistors."  And "since it has so much voltage and current capability that it never clips, it doesn't exhibit any transistor sound."  From my limited experience, thus far, with the system, I can attest to the seeming lack of any high-frequency clipping with the Quads, which gives the speaker a top-end airiness and openness I've never heard from them before.

I wish we had more electrostatics on hand to assess the befores and afters of the InnerSound mating.  But we only have the Dutch Audiostatic panels, which we can't get the company to take back, and these are severely limited in terms of their excursive abilities, and even with the InnerSound, can't be played to anywhere near soul-satisfying loudness.  Yep, they played better and with a stitch more volume and with some of the most perfectly "pure" sound you'll ever hear, but not on any music I'd care to live with, long haul.  We also tried, in preliminary evaluations, the InnerSound with normal speakers, and found them neutral, wideband reproducers, minus most, if not all, solid state artifacts.  Perhaps they are not - and only further listening will tell for sure - as exquisitely and honestly musical as the Danish Gamut amp, but running sans electrostats, they are lovely and musically satisfying.  (Consider this a sneak preview and forgive the lack of detailed commentary - that will be coming.)