Has any had experiecne with the MF 550k superchar?

Take a look at the December number of Stereophile. MF has introduced a 750 supercharger at a much higher price point. In the same review, JA and the Cantus guy he records both remark on how hard and cold the 550 sounds in comparison with the 750. The 550 is now half price everywhere--at all the web-based mail order stores.

Warrenh--read the "Follow up" review of the 550 towards the back of the December number, written by a professional singer. Used both on its own and as a supercharger on his Aleph. Basic sonic characteristics didn't change either way, just mitigated somewhat by the Aleph. His experience echoes Elberoth 2. JA found the 750 much better, but at its price point it would make more sense to start from scratch and get a much better amp, rather than using the supercharger as a $$$ bandaid.

I should have expressed myself more clearly. The reviewer found that the inherent sonic characteristics of the 550 (cold, hard, compressed sound stage, etc. etc.) did not basically change when used as an amp or as a supercharger; they were more pronounced when it was used as an amp, and mitigated somewhat by the interaction with the positive sonic features of the Aleph. The Aleph is one of the more of the more "tubey" ss amps out there, but--yes--certainly isn't an SET.