2. amps-preamps
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HELP , More problems with Bias

Thanks to everyone's help I now know how to set the bias on a tube amp. But, I now have a problem with one channel of my Golden Tube Audio SE-40. The left channel biased without a problem just like it said it would in the manual. The right side, however, is a different story. Each side has three adjusters and three places to take a reading. The reading according to the manual needs to be between 635mV and 640mV but never higher than 640mV. None of the three testing places on the right side are able to be adjusted down to 640. one will go as low as 720, the other two only go down to 950 and 1.045. I hope that someone is able to tell me that this is a tube problem and not an amp problem. What happens if I play the amp with readings in that range? Should I just buy new tubes? Any help would be appreciated, I would sure like to hear my new amp.
richardzerambo
south43
386 posts
 
Hello Brucel483 Your advise on bias is welcomed. I have a Anthem amp1 and it came with ElectroHarmonix EL34's. I would like to change them but with what you advised Richardzerambo I will have to look at my manual to see what SF recommends. Richardzerambo I hope you get through this.
bruce1483
72 posts
 
I don't want to give the impression that it is common to have biasing problems when switching brands of tubes. It is actually rather rare. Most tubes of the same type can be changed for one another with no problems.
dan2112
144 posts
 
Richard, What tubes are you using? I have two Rev 3 SE-40s and had to modify the bias circuit in order to get Svetlana 6L6's to bias correctly. You cen find more information at
http://golden_tube.listbot.com/cgi-bin/subscriber?Act=view_archive&list_id=golden_tube Cheers, Dan
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