#1
Hey all, I just purchased my first tube head (a Bugera 6262) and I bought some new tubes for it (Electroharmonix EL34's) to replace its stock 6L6's. I understand how to bias the tubes, I just don't know what to set the bias to. It tells in the manual what to set it too but won't it be a different number since I'm switching to a different brand and I'm switching to EL34's? Thanks to anyone who responds.
#2
I checked in the manual and couldn't find the value. All I see is where it says to set the selector switch to the correct tube type. My guess is that you could probably set the bias for the 6L6 tubes, then replace them with the EL34s and change the bias select switch. It should set the bias to the correct value. If you have a voltmeter, which you'll need to adjust the bias, you can check it and verify that the value is correct. If not, adjust it to the proper level.
#3
You can't replace 6l6's for EL34's without modification as far as I know. I think there are gonna be heater current problems (EL34's draw more heater current). There might be a problem in that the output impedance of EL34s is different than 6L6s, which means you may need a different output transformer. I think but am not sure. Let someone confirm this
#5
Quote by mcrfobtai
You can't replace 6l6's for EL34's without modification as far as I know. I think there are gonna be heater current problems (EL34's draw more heater current). There might be a problem in that the output impedance of EL34s is different than 6L6s, which means you may need a different output transformer. I think but am not sure. Let someone confirm this


On the Bugera amps you can swap 6L6 and EL34 tubes by just flipping a switch, they are built for both.

The numbers in the manual are useless for setting the bias unless you are using Bugera tubes. Those numbers are also for biasing using the bias jack on the amp and that jack is very very inaccurate. You should use a bias probe between the tube and the tube socket it will be much more reliable.

I can't tell you what to set the 6262s bias for with EL34s though sorry.
#7
Quote by kirkhammett09
Hey all, I just purchased my first tube head (a Bugera 6262) and I bought some new tubes for it (Electroharmonix EL34's) to replace its stock 6L6's. I understand how to bias the tubes, I just don't know what to set the bias to. It tells in the manual what to set it too but won't it be a different number since I'm switching to a different brand and I'm switching to EL34's? Thanks to anyone who responds.


Bugeras run about 480 V
Bias range 38mA - 42mA DCV
#8
The number you bias it to depends on the amp. I was taught to bias using a cathode resistor and then measuring cathode current. Plate voltage*cathode current=idle plate dissipation. You need to bias the amp so that this plate dissipation is 70% of the el34's maximum 25 watts.
Last edited by al112987 at Dec 15, 2008,