Biasing Marshall 9200

[blackarab]

help needed to bias amp using 5881/6l6 tubes ,need to know what proceedure to bias for new tubes ,many thanks Blackarab.

 

[firechief]

Ok so see here a short thread where a knowledgable onwer gives the specific numbers for bias current http://www.diyaudio.com/forums/instruments-amps/202010-marshall-9200-a.html
I asume that there are resistors in the cathodes of the output tubes, if so measure the voltage drop accross the resistors at idle and adjust?

 

[blackarab]

biasing marshall 9200

thanks for your answer , i am getting 494v plate voltage and cathode current is -50v , how should i go about finding the correct current for the new tubes ,thanks for your help.