SOUNDLAB ULTIMATE 545

@atmasphere , While technically true, high powered Solid state amps Like the JC1 do just fine to 105 dB (as high as I have gone) for several reasons. The JC1s due to a programming error I made absolutely fried the high frequency brilliance control and I mean barbequed BLACK and I had no idea this was happening until I smelled smoke. The JC1s merrily baked along without so much as a whimper. Tough amps. 
Next, while the Soundlabs are capable of making plenty of bass the long excursions required below 100 Hz doppler distort everything else the speaker does. I am of the firm belief, know it for an absolute fact, that full range ESLs sound even better, much better, if you use them with subwoofers. This cures the high impedance problem at low frequencies also. The 105 dB is without subwoofers. With subwoofers lord knows how loud you can go, certainly right past the threshold of pain. I would bet the subwoofers would be the limiting factor.
Having said all this there are quite a few Sound Labs owners who are convinced the MA 2 is the best amp to drive them. Hopefully, after I recover from dumping $50K into my system this year and the house renovation required by my wife (her part of the deal) I will be able to afford your amps and maybe a Dohmann Helix and a new Master Bath :-)
pinotnoir, The Antileon should be more than adequate for the time being. I would bet even better than most tube amplifiers with the exception of Ralph's amps. It is class A and 150 watt/ch. I bet it goes even higher in AB. However, next time around regardless of which amps you buy, get mono amps and place them right behind the speakers. This gives you the shortest speaker wires possible, a huge advantage with speakers that have low impedances. You should also run balanced cables to the amps. 

Hi mglik:
Thanks again, You´re right,  I only play vinyl.
Sound in KRONOS PRO and his KRONOS REFERENCE PHONO TUBE PREAMPLIFIER give me a sound that any digital source I´ve tried can´t match.
I´ll try the sound that will emerge from SL-U545 with my Antileon (Dual mono class A 150w amplifier with SL-U545), but the goal will be to feed the system with tubes.
Let you know

mijostyn:
Hope you and your wife enjoy the new house renovation.
Thanks for your  masterclass, take taking note of every detail.
Before you go forward, give a chance to KRONOS TURNTABLE.
My experience (and humble opinion) with "deep vinyl track" provided translate to 5ft dimension.
A complete concept vinyl system reproduction.

While technically true, high powered Solid state amps Like the JC1 do just fine to 105 dB (as high as I have gone) for several reasons. The JC1s due to a programming error I made absolutely fried the high frequency brilliance control and I mean barbequed BLACK and I had no idea this was happening until I smelled smoke. The JC1s merrily baked along without so much as a whimper. Tough amps.
Next, while the Soundlabs are capable of making plenty of bass the long excursions required below 100 Hz doppler distort everything else the speaker does. I am of the firm belief, know it for an absolute fact, that full range ESLs sound even better, much better, if you use them with subwoofers.

There is a reason Sound Lab made the B1 subwoofer, which was the size of the A1s they made at the time (back in the 1990s). But the use of subs isn't something limited to Sound Labs- many speakers benefit from not having lots of excursion.


You have confirmed my comment- in order to work with Sound Labs your solid state amplifier needs to be high power. Since the impedance of almost any ESL varies by about 9;1 to 10:1 from the bass to 20KHz, quite often the solid state amp is making far too much power at 20KHz (A high power amp can probably double power as impedance is halved, but ESLs don't work that way, they need the same power regardless of impedance at a particular frequency in order to make the same sound pressure). Since you have to throttle it back somehow, the Brilliance control becomes a target as it has to dissipate some energy.


The trick of course is finding a solid state amp of that sort of power that simultaneously actually sounds like music (instead of like electronics); traditional class AB designs can be challenged in this area due to a lack of feedback at higher frequencies- which causes them to be bright and harsh (due to distortion) as I mentioned in my prior post. Its this particular problem which is why when distortion measurements are published, they are only measured at 100Hz. 1KHz and 10KHz distortion specs are usually not measured or published, but if they were you'd see that the distortion rises with frequency. 


This lack is caused by inadequate Gain Bandwidth Product, which is engineering gobbledygook for "the amp runs out of feedback at higher frequencies". You can't just add more feedback- that takes more gain, part of that Gain Bandwidth product thing, and at some point all the frequency poles in the amp cause so much phase shift that at a certain frequency the feedback is positive rather than negative so the amp can oscillate. The engineering expression for this is 'the phase margin of the amp has been exceeded'. This is part of why the Brilliance control is so important on the Sound Lab when using solid state amps- you have to tone down both the excess energy and the brightness caused by distortion.

The SoundLab speakers cannot reproduce any significant bass above low volume. I have the A1’s and at low levels they deliver satisfying bottom end. If you push them then it’s game over… I use two Sunfire 300’s run in mono and augment the basement with a pair of subwoofers using a CR-1 crossover.