best preamp under 4000 to match 4b sst

My suggestion is to buy a stock preamp. Alterations to the original unit, whether
parts or design, may change the sonic character of any component, and the
pool of potential buyers for altered gear is always smaller than the pool of
potential buyers for stock versions of the same component, especially gear with
the pedigree of Lamm (or VAC, or Pass Labs, or any other well respected brand).

I agree with Tvad's list of good preamps. For your budget I would absolutely include relatively inexpensive Joule-Electra MkII - most important, it has remote (kidding, it has remote but its not the most important). Increadible "right", natural, truthfull to real music unit. It has received Golden Ear Award from Harry Pearson of TAS last year and for goooood reason. Plus, one of the most reliable audio equipment there is (e.g.tube life time is more then 5 years !)

Call Joule-Electra may be they have some demo or "B" stock (with their finish, their "B" stock is equal to triple A of somebody else) or they will refer you to some really good dealer - if there is such thing ;--)
All The Best
Rafael

Parasounf JC 2, and tun them balanced. If yourt source is not balanced, time to upgrade. Raysonic 168, 228, 238 are balanced designs. My 168 is now for sale, as I replaced it with the 228. Have a max budget for CD of <$2,000, I'm your man. FYI, the variable tube output stage is so good, I sold a %3K preamp

I had a Cary SLP98 that sounded pretty good with the 4bSST.

A Premium modded Counterpoint is a great match with Bryston amps in case you come across a deal on older one....options are a good thing as usual here....