Peavey VB-3: How to properly bias the power tubes of a tube amp

[@huskobar4545]

Great video! Very helpful...you might want to check the other 3 rear-most power tubes as even though they were originally matched I've found some out of range by some 10ma. That way you can get an average of 25ma by taking into account the measurements on the other tubes. I had one that was 38ma when the tube next to it measured 23ma, even though they were supposedly matched...

[@Bassguitarist1985]

Thank you for the advice! Interesting how that works out having a matched set that they can be not so closely matched... I got a gig this weekend and plan on using it :-)

[@huskobar4545]

@@Bassguitarist1985 Great! You should post a video of your tone. Regarding power tube matching, I'm sure they were actually matched at one time. But, the nature of the beast nowadays is they don't all age the same and some drift much more than others, not counting any rough handling or drops in shipping, etc...it doesn't take much.

[@Bassguitarist1985]

@@huskobar4545 agreed! Oddly enough I found that the bias voltage was set to -46.2 volts of DC when I got it off the truck the other day. Now it is set to -45.5 volts. I believe the gentleman that used to own this amplifier that it has very low hours as he mentioned he has not done any biasing since he bought it back in 2010 timeline i think. I have plenty of Peavey gear to sample the tone and I would like to get a nice DI tone from it. That is certainly on the docket for me!

[@Bassguitarist1985]

@@huskobar4545 hey, the DI tone sample is coming! Fixing the DI actually with a nice Jensen transformer to get rid of a nasty ground loop that the electronic balanced DI cannot get rid of. I beleive it may be a chassis/signal ground issue between the 7 PCBs inside. John just scored a VB3 for himself and will be checking it out this coming week. My state is going into heavy public place restictions again, and my day job is down to essential employees only so Ill be working from home for the foreseeable future. Will be easier to jam out inbetween meetings and such!

[@huskobar4545]

@@Bassguitarist1985 Hi there...sorry I didn't get a chance to respond sooner. I didn't get a chance to try my DI yet. Do you find it is frequency compensated? Not really a cab simulator, but the older Peaveys at least had the high end rolled off since tweeters weren't used in bass amps back then...my old Alphabass has an amazing DI and line out. Dead quiet, and amazingly needs little eq even when using massive distortion...the high end sizzle is already filtered out. Let me know what you find out from John...