Any Shindo preamp
Wait til you here the comments on this one....
Nad / Parasound / Rotel(which I like),...these are some of the pre-amps I have experienced... NONE..can touch the spacial musicality of my vintage...Marantz 600 AV Pre-Processor. A 5.1 / 2 channel gold mine!!! Find one and give a listen. If you get a lead on the MANUAL for this thing... HIT ME BACK PLEEEEZ! Darn thing seems non-existant. 600AV ROCKS!!
The Eastern Electric Avant pre-amp, particularly with an NOS rectifier tube and discreet op amps is a excellent and low-cost preamp. Not the best that I have heard, but you didn't list a price range.
If price is no object, ask Frank Van Alstine to build you a custom, one-off, fully discreet, hybrid preamp.