Hi fertguy
I want to start by saying something is very wrong. I’m not going to list all the preamps I’ve owned in the last five years but I can honestly tell you that in my opinion, my BHK preamp is a tremendous value and just a killer performer. After about six months of using it and making sure it was completely broken in, I bought a pair of nos vintage (1960’s) Telefunken 12au7’s and you would think it was a different preamp. Those tubes transformed that preamp like you wouldn’t believe. I’ve owned it for about two years now and I realized that I like the 6 volt tubes you are able to use in it better than the 12 volt tubes. (there are two jumpers inside that have to be changed, one for the voltage and one for the bias).This 6 volt family of tubes consists of 6dj8, 6922, 7308, or cca’s.
If if you try a pair of vintage nos tubes and it doesn’t sound much better, then something is wrong with yours. I have had preamps that cost three times what the BHK costs and I like the BHK better. IMHO dollar for dollar, it’s one of the best sounding most musical preamps out there with the right tubes in it.
If you put in a pair of good nos vintage tubes in it and it doesn’t blow you away, then I would send it back to PS Audio and have them figure out what’s wrong with it. Good luck.
Scot