I've had 3.7's for 2 years plus now and have tried them with several amps.
My favorite by far is the Bryston 7bsst2.
I would probably swap it only for a pair of 28bsst2's....
3.7s need a lot of juice to open those speakers up, but if you give the
speakers prodigious amounts of power, you will be rewarded with lifelike
sound that is almost scary sometimes.....
I've had all sorts of speakers over the years and with the 3.7's I really
think I've reached the end of the road......no desire at all to swap
them for something else.......
I use a tube preamp (CAT SL1 Renaissance)