biasing a silverface princeton... and cool mods

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9/25/1997 3:54 PM

steve

biasing a silverface princeton... and cool mods Hi,   I've built amps before, but I've   run into a problem. I have a fixed   bias in my amp so I have yet to bias   a amp in a service oriented manner.   My question is what is the correct   way to bias power tubes. You can   check the grid and plate votage...   but what about crossover distortion?   I have a old scope but it doesn't   have a dual trace. Do I need to   get a signal gen. and a dual trace   scope? Can I just look at the   negative voltage on the plate?   I'm helping out a friend with his   Silverface Princeton, I think it's   a fixed bias so how critical is it   to mess with bias. He bought a   matched set of 6v6s. Also the   vibroto isn't strong enough, is   it posible to change some of the   values to make a stronger effect?   I was going to put a choke in the   power supply and perhapse take the   25/25 caps off the front end because   he says it sounds to raspy. I think   the amp is going beyond the   compression stage and geting some   nasty clipping. Any suggestion are   very very very welcome!!!!! He is   looking for the warm Tom Petty   overdrive sound.   Thank you,   Steve

 

9/25/1997 9:22 PM
R.G.	For how to bias, read the Tube Amp FAQ section on biasing. http://www.eden.com/~keen/     It is necessary to touch up the bias every time you change output tubes.

 

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