PS Audio BHK Signature Preamp?

Purchased mine in 2021and extremely pleased

The input stage is tube based and the output stage is solid state

I've experienced deeper, wider, sound stage, an increased separation of instruments and an overall wider dynamic range of highs and bass

Good products made by a good company, IMO

@stevewharton An impressive endorsement. Which preamp(s) are you comparing with the PSA?

I had the PS Audio BHK about 2 years ago.  It replaced an Ayre K5xeMP.  The stock tubes were awful IMO.  The preamp was bright and I found awful with stock tubes.  Rolled in NOS Tunsgrams and it was sweet and engaging.  Step up from the Ayre.  It was paired with VTL MB185s and a Rogue Audio Hydra.  

I have since had a few preamps that I think are as good or better.  The AVM PA 5.2 is as good with a better feature set like tone controls and optional cards.  The Art Audio Conductor (much more expensive SE preamp) was significantly better with my Art Audio and Rogue amps.  

The PS Audio is best in a fully balanced environment with fully balanced DAC and power amps.  I would not bother if you have SE amps.  You will almost certainly want to roll tubes.  You will find quite a few different choices but I had great luck with the NOS Tunsgrams.  You should be able to find this used for ~$3500 and is a strong value at that price point.  

I've used a BHK preamp in balanced mode with a PS Audio BHK250, PS Audio Stellar M1200 monos, and a Zesto BIA 120 and it has been wonderful with all three amplifiers. I've found the professional reviews to accurately reflect my experiences with the preamp so no need to repeat the litanies of praise found there. My Tidal Piano Cera speakers are rather revealing and I found the choice of preamp tubes considerably affects the sound of the preamp in my system. I also did not care for the stock Psavane tubes and Gold Lion 12au7's are a fine modern replacement. Older tubes from RCA, Raytheon, GE, etc. offer different flavors. You can also run 6dj8/6922 family tubes in it with a switch of jumpers on the circuit board. Telefunken 7dj8s were my favorite in that family of tubes. That said, I generally found 12au7 family tubes to be a bit quieter and with less of a tendency to exacerbate unpleasant sibilance in recordings. Unlike many other components, I haven't found different footers to affect the sound very much. Power cords are a different story, I've tried a dozen or more and they all sound different. I agree with the prior post that it's a strong value at used prices. 

Thanks to all for sharing your experiences and buying tips. Definitely want to try this one if I can score it at a decent price. Will be prepared to roll tubes as needed.