Marshall Amp Forum - View Single Post - SuperBass EL34 to 6550 bias circuit INFO need PLEASE

David_Well · 11-05-2009, 11:15 AM

Some People actually do it, a switch between the 120 and 240.
Other use a variac to drop voltage but not less then 70VAC.(Van Halen)
Older Marshall like the 67 plexi have a power selector.
And like you suggest, taking off 2 valve reduce the output Wattage at 50W
Some use Yellow jacket and use EL84....

Seem's to me thet is many way to do it...Is just to find the one that not going to damage the and and no need to rebias....

11-05-2009, 11:15 AM	#12 (permalink)
David_Well Member Join Date: Mar 2009 Posts: 67	Re: SuperBass EL34 to 6550 bias circuit INFO need PLEASE Some People actually do it, a switch between the 120 and 240. Other use a variac to drop voltage but not less then 70VAC.(Van Halen) Older Marshall like the 67 plexi have a power selector. And like you suggest, taking off 2 valve reduce the output Wattage at 50W Some use Yellow jacket and use EL84.... Seem's to me thet is many way to do it...Is just to find the one that not going to damage the and and no need to rebias....