McIntosh 501 or 602 for Magnepan 20.1

SimAudio W10's might work well with the 20's. They work very well with the 3.6's. Remember that the Mac's don't double into 4 ohms. I understand the power stage is looking at the fixed impedance of the Autoformers, but I tried the MC252 in my system on the 3.6's and it shut down on thermal overload after a few minutes of playing at moderate levels.
I've also driven a 600w (into 4 ohms) digital amp into clipping on the 3.6's....I'd get an amp with high current capacity into lower impedances and avoid any chance of under-powering the 20's.
Rooze

I meant Classe Omicron or Omega MK 1--they're available for 5-6,000,
On my 20.1s, I went from Omicron MK to the mono pairs you mention. Yes, the monos are better, but the originals are not that far off.

Another suggestion to try might be Steve McCormack's DNA-500. Lots of current and power(500w/900w) with excellent sonic presentation.

I had the MC602 for about 10 months and I'm turely impressed with the performance of the unit. Based on it's power, sound and yes, those beautiful blue eyes, I purchased the MX135 video control center. I've listened to the 402, 501, 602 and for me the choice was the 602. The next amp for me, MC1201!! Make no mistake, Mac amps are AMPS.

Gladstone: Are you bi-amping your MG20.1s? From my understanding that's one of the first major improvements you can/should do once you have even a half-decent amplifier. (Just consider the fact that Jim Winey is bi-amping his own 20.1s and recommends this wholeheartedly). One of the nice things about bi-amping the 20.1s is that the low and high require about the same power, so using identical amps is not overkill in any way.

AFAIK, getting rid of the "mediocre" passive crossover is a major improvement. I don't want to buy 2nd hand amps, so my only option would be to get 4 brand new Omegas. That's $50,000. Considering that the JC1's are $12,000 that's one heck of a difference. I doubt *I* could justify paying $38k more for the sound of the Omegas...

Peter