add bias pot to 1988 Carvin X100B EL34

[sambo69]

I have a 1988 Carvin X100B with original EL34s. I want to replace them with different models of EL34s to get a different sort of tone. I want to ensure the bias is correct but this particular model/year doesn't have a bias pot. Does anyone have the steps to install one? I can solder pretty cleanly but don't know the specific steps. I have biased an amp before ( but it has a bias pot).

Thanks in advance.

Sam

[Jazz P Bass]

Here is Carvins link for the schematic.
Link:http://www.carvinservice.com/crg/sch...0Schematic.pdf
The specifically state "select R127 for idle current of 100ma".
I guess you could put a 100K pot in place of R127.
Solder the wiper to one of the outside legs or the pot.

[sambo69]

add x100b bias pot

thank you. I've seen that schematic before; The work doesn't sound to complicated as long as you do neat work. Amp's with a tech right now, if he can't do it, I'll give it a shot.


Thanks again.

Sam

[Gtr_tech]

None of the x-amps had a bias adjust pot. I've added them to all of mine.

[sambo69]

add x100b bias pot

thanks fellas;

GTR_Tech since you've done this before, is there anything specific I need to watch out for? Also, do you have a recommendation as to tolerance and wattage?

Sam