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One channel gets very quiet after bias is adjusted

I have SET Antique Sound Lab amp, when I turn the bias pot all the way clockwise, one of the channels gets very quiet The other channel gets louder and punchier. The tubes are from a pervious owner. Are these tubes possibly unmatched or one of them is bad?
malammik
tpreaves's avatar
tpreaves
2,686 posts
 
You are routing most of the current to one side when you do that,so sure,one side will be louder than the other.Why do you feel the need to do this anyway?Just curious.
malammik OP
10 posts
 
My right channel sounded less lively and tiny bit less lound on a number of records. So I swapped the tubes left and right. It is a 300B SET amplifier and now the left channel had this kind of laziness to it. One of the tubes where laziness is observed has small burn out stripe at the very top.
thorman
1,262 posts
 
Time for new tubes!!!!!!!!
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