PS Audio BHK lacking..


I bought a used PS Audio BHK preamp to replace my Rotel.  It sounds thin with no depth & bass compared to my Rotel so I let it run for over an hour with no change. I'm new to tubes so I'm looking for ideas. New tubes or what?
128x128fertguy
Well, the BHK's bass certainly bested my VAC Ren Sig II, which retailed at a distinctly higher price range in its day.  Haven't heard a Modwright preamp.  I'm guessing the BHK's MOSFET output gives it bass authority, but you can play with tonal character with tube choices, so.....
There may be something wrong with your preamp outside of tubes-There is no way it should sound as poorly as described if all is well. What kind of amp are you pairing with? Have you played around with the current jumpers? If it is a tube issue, there are plenty of options out there ranging from the inexpensive to more pricier options. I have played around with a number tubes, including 6sn7 tubes w converter. I am currently using Siemens CCA that sound incredible, granted they cost quite a bit. My runners up are Telefunken 6922 and the Tungsrams as suggested by BHK. just be sure to get tubes that are tightly matched otherwise you will suffer from volume pops. Best of luck and hop it works out!

Surfmuz

I owned a Parasound JC2 for several months. I kept it long enough to make sure it was completely broken in. I couldn’t wait to terget rid of it. I found it to be just mediocre at best. Very polite and very boring. 

With regard to your question about a hybrid design, the reason BHK designed it like that is it’s quieter. You still get the tonal color and accurate timbre from a tube design but because it only uses 2 tubes, there is much less noise (tube rush). Best of both worlds. You have to remember, BHK has been designing preamps for 50 years!

I bought the BHK preamp and it just blew away the JC2 even with the factory tubes. After about six months I decided to try some nos Telefunkens 12au7’s from the early 1960’s and those tubes elevated it to a whole new level. Those vintage tubes made a world of difference to the point of it was almost unrecognizable. I’ve had the BHK for over two years now and the more I improve my system, the more I appreciate how good that preamp is. For $5995.00, I don’t know what would beat it. They come up on Audiogon every once in a while for $3000 - $3500.00. Get one and get some old nos tubes from Mullard, Telefunken, Amperex, Siemens, just make sure the tubes are from the 1950’s to the 1960’s and you will be amazed. Good luck.

Scot

I catch a little heck because I’m using a TFM 45 Carver. I bought the amp new in the 80s. About a year ago it was completely updated with new & better everything. Long list. It is dead quiet, runs cool & is rated at 375 WPC. They told me when they rebuilt it it would be tube like. I'd never had tubes so how would I know. I used to have it on a set of Kappa 8s & it was wonderful.