Well I'll throw out a vote for a Quicksilver Pre, line or full-function, dependent on your needs of course. I've used the ff version with the M-80 and other tube and solid state amps and it worked flawlessly. I like Quicksilver's "house sound" as it is very faithful to the source and maintains excellent neutrality while still giving a wide, deep soundstage. Can be very 3D with the right material.
EDIT: I want to add that I do not have any experience with Belles gear so I can't compare.