I need a good Preamp

knghifi, tell me about FPB300 and the FPB600. How were they different and what did you like/not like about them.  Know how they would compare to my FPB 350mcxs?

Check out the PS Audio BHK preamp. It's well under your budget, sounds great, tube rollers delight and will mate with any amp. 

wemfan, FPB300 and FPB600 are cut from the same cloth. I prefer the FPB600, felt it had more control, like driving a V8 vs V4.  Even around town at low speeds, you always feel the V8 torque and power.   

I'm familiar with FPB650 mono so my guess your 350mcx is similar to the FPB600 with better separation.

Before FPBs, I had a Krell KSA100s and it was very very dark in comparison.

At the time, Krell was my favorite SS amp.  Great bass, neutral, dynamic but bright and hard and always use MIT cables to tame it. The ONLY reason I sold FPB600 is try something new.   It's one of my all time favorite amp with great great memories.

VAC preamp is a great match.  It has low impedance so can drive anything.  Very sensitive to tube rolling so you can tailor sound to your taste.

I've heard good things on PS Audio BHK preamp so worth checking out.

Wemfan,
I too have a McIntosh MC452 and had a McIntosh C50 (solid state) preamp, which I replaced with a C2500 (tube) unit, sounded a little sweeter than the C50...but then swapped out the stock tubes for a set of Genalex Gold Lions, once broken in, just sound so "musical".  The C2500 is a "keeper".  As this has recently been replaced with a C2600, you might pick up a good deal on one of the remaining C2500's.

Vac or an ARC Ref 5 se. Different voicing, so this is a personal choice