PS Audio BHK preamp owners


Hi

This question is aimed at PS Audio BHK preamp owners regarding the tube bias. I understand that the bias is user adjustable by just moving an internal jumper pin (pretty brilliant). The unit ships with 12au7 tubes set at 4 milliamperes. When the jumper pin is moved the bias is increased to 5 milliamperes. I would like to know if anyone has tried this and if so did you like it? Thank you.

Scot
scothurwitz

Showing 2 responses by scothurwitz

Jbrrp

actually, it’s the other way around, PSAudio suggests 4 miiliamps for the 12au7’s that they ship the BHK pre with and 5 milliamperes when you change to the 6 volt tubes. 

My question is, and I wasn’t clear about it when I first posted the question, has anyone tried a 12au7 and increased the bias to 5 milliamperes? I don’t want to just try it if it’s possibly going to hurt the preamp. A gentleman on the PS Audio forum tried a Tungram 7dj8 which is supposedly Bascom’s (the designer and the B in BHK) favorite tube and he set the bias first to 4 milliamperes and then tried the 5 milliamperes setting and stated, and I quote, “I was amazed at how such a small increase of just 1 milliamperes can make such a big improvement”. Now I’m curious but I don’t want to blow the damn thing up to fing out. Thanks.

Scot
Tomcy6

good advice, I wii give them a call on Monday. Thanks. Do you know if they stopped their own forum? I can’t find any recent posts. 

Scot