More Efficient Sound Labs on The Way?

I owned the new cores and estimate the efficiency gain was at least 6 DB. Soundlab is shooting for 9 DB and perhaps when completely broken in, they may well achieve that.

As for the A-1, it is no better performer than the M-1.

The A-1 costs more due to the premium wood clad trim and finish. If your aware of that and want the wood, then that's an excellent choice. If your looking for performance to dollar ratio, the M-1 is the value in Soundlabs line of speakers.

I owned the A-1 and later the U-1 (physically identical to the A-1 and M-1, except for the premium steel frame). The deep bass and impact is improved with the Ultimate, making it the flagship product.

Regardless of which Soundlab you choose, the performance is in another world beyond the Quad 988. I'm not just referring to bass performance which is the most obvious gain, but textures, soundstage, dynamics and bandwidth as well.

I would expect the Thors to have no trouble driving the Sound Labs, though you might want to check with Paul Marks for his thoughts. I can describe the impedance curve to you if you'd like. The Thors use the same output tube complement as the SoundLab-friendly Wolcott amplifiers, and have a beefier power supply and probably even better output transformers (of course they also retail for 2.5 times the price of the Wolcotts). The Thors are rated very conseratively, so don't be put off by the "only 150 watts" rating.

Sound Lab has been shipping the higher efficiency panels since the early part of this year, and the feedback I've been hearing is consistent with Albert's estimated 6 dB efficiency increase. In addition, dynamic contrast and liveliness are improved, though this may be a side-effect of the amplifier not having to work so hard.

Sound Labs are still a difficult load, and at best of only moderate efficiency, but at what they do well their performance really is "in another world", as Albert said. Disclaimer - in case anyone doesn't know, I'm a Sound Lab dealer.

I'll chime in, too, as I've owned Sound Labs for several years and also am a Sound Lab dealer. The Thors may likely be a good match with Sound Labs, depending upon how they can handle the complex load. Other than that, I can report that a substantial 100 W/ch tube amp had no trouble driving my U-1s which employ the current technology. I've heard of 150 watt tube monoblocks driving MBLs (efficiency in the low 80s at best) extremely well, while some other 750 watt monsters, also tube, fell apart trying to drive the same speakers. Quite a different speaker load, but maybe you see my point that you can't rely on wattage ratings.

As already mentioned, Sound Labs remain a tough load, but the higher efficiency technology used beginning this year allows a wider range of suitable candidates for amplification.

The improvement in efficiency on my Sound Labs was noticeable although I didn't measure it, but the increased detail and responsiveness are at least as noticeable. I suggest these latter improvements are at least as much a result of lower distortion in the backplate components as they are of lower amplifier distortion.

I've owned several other ESLs through the years. Very few could match the Sound Labs in some areas, while none of them even came close to Sound Labs overall for for a completely satisfying music listening experience. I purchased the Sound Labs as a consumer and ultimately decided to become a dealer for them.

Brian