Which One Amp for the Magnepan 3.6's?

Between the 3 you list, I'd go for the JC-1's (def not the krells
)
I agree that the Pass Labs x 350.5s would be an awesome match. I used to use class cam 350's with my 3.6r's - was very happy with that pairing. I like the class even better than the JC 1's. I switched to Lamm M2.2's a few years ago (got a great deal on a used pair) and could not be happier.

Also, second the nod on the mye-stands. They are a HUGE improvement and will do alot of good for not that much of a financial investment.

All have the above have merit.Magnepan uses Bryston amps when they are on the show circuit and have for some time.You may want to consider that choice.

Didn't Audio Research just introduce an amp at CES that is supposed to be a great match to Magnepans? I saw it in one of the CES recaps on Stereophile, I believe.

Audio Research DS450. $7995.00. 450 Watts per channel.

Sunfire Signature(600Wpc) load invariant amp is the best so far from Bob Carver.