[Amps] SB-200 idling current and plate color

[Mike Waters]

My SB-200 draws 90 mA of idling plate current, and both 572B plates show a
red color with no drive.

Is this red color OK, or should I increase the grid bias? (I think I should
have increased it when the tubes were new, but I procrastinated. :-)

When the Svetlana tubes were new a few years ago (when they apparently DID
come from Russia and not China), the idling current was 100 mA. I was
always going to increase the bias, but never did.

TIA,
Mike
www.w0btu.com