Valveking bias mod

[VanR]

Did the adjustable bias mod on my Valveking 112 over the weekend and boy did it improve the sound of the amp. Before the SED 6L6GC's were biased about 20mA on my meter. Did the adjustable bias mod and got them up to 40-42 mA (PV is 425 volts) and the amp just sings now. I'm gonna have to order a 25K locking bias pot from Weber and re-do it (just soldered a 25K guitar pot in for now with 22K safety resistor), but now I know it works anyway. Why Peavey fixed biases these amps so cold is beyond me.

[cap47]

Originally Posted by VanR

Did the adjustable bias mod on my Valveking 112 over the weekend and boy did it improve the sound of the amp. Before the SED 6L6GC's were biased about 20mA on my meter. Did the adjustable bias mod and got them up to 40-42 mA (PV is 425 volts) and the amp just sings now. I'm gonna have to order a 25K locking bias pot from Weber and re-do it (just soldered a 25K guitar pot in for now), but now I know it works anyway. Why Peavey fixed biases these amps so cold is beyond me.

Be sure to put a resistor of about 6.8k to 15k in series. You can use my link in the sig to go to info on how I did mine. Ultimate Guitar site, look for mods in the WIKI!

[VanR]

Yeah I edited my post to say I put a 22K resistor in series with the 25K pot as a safety resistor. I've looked at your page and thanks for putting that up. It's what I used to do the mod although I used a 25K pot/22K resistor instead of your 50K pot/15K resistor. It's what I had in my parts bin. Got to get a locking 25K pot from Weber though as I'm a little leery of the pot I used.