while not owning a 3B-ST I have paired a number of tubed preamps to larger Bryston amps (4B-SST/14B-SST/7B-SST2). Hovland HP-100, Rogue Magnum 99, Audio Horizon, ARC LS-26 & Ref 3, Lamm L2 Ref and LL2 Deluxe (I think I got them all).
Of the units that are in your budget range (some of which have to be bought used) the Hovland was very good, not as "tubey" as the Rogue but offered up more detail. The LL2 Deluxe, IMHO, was the best of the lot - a hint of warmth (you can tube roll to adjust to taste) and presented the best overall presentation - soundstage beyond the speakers and as much detail as the Hovland. I think of all the tubed preamps I have owned it offered the best bang for the buck.
Just my experience, YMMV