How To Install a Bias Pot on Marshall 3203

[Baktown]

Greeting all,

Brand new to the forum, great place!

Quick question: I just picked up a 1987 Marshall Artist 3203, SS preamp and 2 x EL 34 power section. Changed the PI tube to a NOS RCA 12AX7A I found at a yard sales (along with 150 other assorted tubes), and it really makes this little amp sparkle! It has the factory tubes still in it, and they seem to be running really cold, which I understand is normal for this amp since it has fixed bias. I want to install a bias pot so I can tweak it, but I want to make sure I really understand how to do it safely and correctly as I don't want to fry the transformer. I found an old thread about this on here, but it stopped short of really telling how to install a bias pot.

Any info and/or pics would be greatly appreciated!

Rick J

[Baktown]

Or how about a generic quick and dirty tutorial on installing a bias pot or trimmer? Anything will help.

Thanks,

Rick J

[mrmudcat]

Rick start here !!


http://www.el34world.com/Forum/index.php