#1
Hey again,

I've bought myself some new JJ EL34 tubes to replace my tubes on my Bugera 333xl because the last ones blew during recording a few weeks ago. I've had the Bugera just over a year now so i've been told I shouldn't be worried about other problems and that they were just worn.

I have a gig tomorrow night and heard that I should be able to bias it myself with a voltmeter, but after a little research now it seems that I need a bias probe which I can't get hold of before the gig.

Is there any way I can safely bias the EL34 tubes in my Bugera 333xl without a Bias Probe?

I searched but found nothing specific to this amp, and saw in other threads that did mention the 333xl that it was limited (or something similar) so it's a little different.

Any help is greatly appreciated, thanks!
#2
you dont need a bias probe. the 333/333xl have an external bias point. it is next to the power tubes and looks like a RCA jack. the knob next to it is what you turn to adjust it. Just make suer you keep the selector switch in the EL34 position, and not the 6L6.
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#3
Thanks, hopefully I can work it out!

Edit: Ok so I know where to adjust it now, how do I know what number to change it to? (yes very vague/ poor knowledge of Biasing)
Last edited by Lr-Mtb at Mar 10, 2012,
#4
really you can bias to what you prefer tonaly, but the factory settings are about 40ma so if you bias a little hotter, the tone will improve. At least that was my experience with my 333
2002 PRS CE22
2013 G&L ASAT Deluxe
2009 Epiphone G-400 (SH-4)
Marshall JCM2000 DSL100
Krank 1980 Jr 20watt
Krank Rev 4x12 (eminence V12)
GFS Greenie/Digitech Bad Monkey
Morley Bad Horsie 2
MXR Smart Gate
#5
I had Bugera EL34's in before and now have JJ EL34's to put in. Would I be ok just to switch them around and leave the bias knob in the same position because it worked for the last set of tubes? it's a quarter turn from the left, if that makes sense.
#6
Quote by Lr-Mtb
I had Bugera EL34's in before and now have JJ EL34's to put in. Would I be ok just to switch them around and leave the bias knob in the same position because it worked for the last set of tubes? it's a quarter turn from the left, if that makes sense.


Not really, but it might work for the gig. Though Bugera has a biasing guide on their web page.
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#7
I've found information on the adjustment that uses a multimeter though a socket on the outside of the amp so I don't have to take it apart instead of a bias probe. I'm going to try that as although people say it's off, it would be better than leaving it as it is. Then i'll try get it to a tech to bias it properly after the gig because I can't before.

I've swapped the tubes now, just not done anything with it. Any links to more articles that describe what to do because what I've found is a bit vague :/
#8
Quote by Todd Hart
Shooting your friends with a real gun is a definite faux pas.

Quote by mystical_1
Professor Plum in the Studio with a new Amp

Quote by snipelfritz
If only I were the only one at home right now. I don't need my parents asking who Mr. Wiggles is.