previous: Steve Slick Question about a Crate VC5115 bias adjustment -- 5/25/2000 5:23 PM

ray, here's a post about this amp fromawhile back

5/25/2000 6:30 PM

marleyman

ray, here's a post about this amp fromawhile back BTW, the amp is mine and was wanting to put new tubes in, and was wondering about re-bias. it has GT EL84S tubes in it now, and was wanting to try something different (i.e. Svetlana, JJ/Tesla, or others) and waswondering about biasing first...the GT's are a hardness rating of 6.     anyways..here is the post from awhile back       Mike-     The design of the Vintage Club (i am assuming that this is the fixed bias version) does not allow for the bias voltage to be varied. You would have to derive bias voltage in a different manner in order to vary it. i.e. create a new bias circuit off of the B+...     I worked on one of these for a friend about a month ago, and i was desperately trying to get the bias adjusted differently, but to no luck. Fianally fellow ampagers set me straight as to how this circuit functions.     Unless you want to spend a lot of time messing around with things... I would leave the baby stock and get a fan and blow it into the back of this baby... (the power tubes are being run at about 110%-115% of their rating, i think that my friends ran the EL84's at 375V on the plate, and about 38mA per tube...This cooks them pretty well...(Inspiration to keep this baby stocked with fresh power tubes..))     *end of rant*   Have Fun!   Rob W.     Ps.. I think i still have the posts around from my discussion about this amp... Lemme know         thanks!     marleyman

 

Replies:

eth Yo! That amp may have a bias servo... -- 5/25/2000 10:21 PM Graywater From the Schematic Fellers -- 5/26/2000 11:33 AM