hi all
i was discussing about the (dis)advantages of having el34 vs. 6l6 tubes in a laney amp, and a question popped up whether those laney amps are fixed bias or not.
on the back there's a switch called 5881/EL34 which basically adjusts to those types of tubes. now, afaik the only way to do this is switching between two different resistors that set the bias for the selected type of tube. the question is, if there is a resistor that sets the bias "about right", it is not possible to bias the amp, is it? at least not without replacing those resistors with a trim pot, or am i wrong? i guess i am wrong, because i recieved this mail from laney (the question was whether i should have the amp biased after a tube change or not)
"Hi there,
While it is not essential for the running of the amp (once you have set the switch for the correct type of valves that should be OK), we do recommend you get the amp rebiased to get the best performance from it.
Thanks, "
now, i guess it is possible to have it biased [img]/images/graemlins/laugh.gif[/img] can anyone explain how that works?
greets
fragle
i was discussing about the (dis)advantages of having el34 vs. 6l6 tubes in a laney amp, and a question popped up whether those laney amps are fixed bias or not.
on the back there's a switch called 5881/EL34 which basically adjusts to those types of tubes. now, afaik the only way to do this is switching between two different resistors that set the bias for the selected type of tube. the question is, if there is a resistor that sets the bias "about right", it is not possible to bias the amp, is it? at least not without replacing those resistors with a trim pot, or am i wrong? i guess i am wrong, because i recieved this mail from laney (the question was whether i should have the amp biased after a tube change or not)
"Hi there,
While it is not essential for the running of the amp (once you have set the switch for the correct type of valves that should be OK), we do recommend you get the amp rebiased to get the best performance from it.
Thanks, "
now, i guess it is possible to have it biased [img]/images/graemlins/laugh.gif[/img] can anyone explain how that works?
greets
fragle
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