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Post by edoetsch on Jun 11, 2006 18:23:04 GMT -7
I can replace the fuse (3 Amp blew in this case) easily enough, but had some questions. I was tweaking some tubes in the back etc. and changed just 2 of the EL84's with another pair and turned the amp on with no speaker plugged in and not in stand-by. I am thinking this is likely the issue and not the fact that the 2 new tubes were there. Does this sound correct? If this is the case, the solution is to replace the fuse and never turn on the amp without a speaker load.
However, I have occasionally turned on the amp and not had a speaker load. I even had a guitar plugged in which I strummed and was therefore trying to send a signal to the speaker. The fuse did not blow.
Is it that I put new tubes in and therefore released some capacitor or something causing this particular power up to blow the fuse?
Is it possible the tubes were unmatched or interfered with each each other. There were two GT EL84s tubes near the pre amp tubes and I had put 2 JJ's in the other sockets.
Also, on the fuses, I have some old fuses from my Peavey Classic 50 that are identical to the blown fuse except they do not say 3A specifically. Everything else is identical except that there is no amp marking AT ALL. Can I use this fuse?
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Post by benttop (Steve) on Jun 11, 2006 19:00:31 GMT -7
I can replace the fuse (3 Amp blew in this case) easily enough, but had some questions. I was tweaking some tubes in the back etc. and changed just 2 of the EL84's with another pair and turned the amp on with no speaker plugged in and not in stand-by. I am thinking this is likely the issue and not the fact that the 2 new tubes were there. Does this sound correct? If this is the case, the solution is to replace the fuse and never turn on the amp without a speaker load. However, I have occasionally turned on the amp and not had a speaker load. I even had a guitar plugged in which I strummed and was therefore trying to send a signal to the speaker. The fuse did not blow. Is it that I put new tubes in and therefore released some capacitor or something causing this particular power up to blow the fuse? Is it possible the tubes were unmatched or interfered with each each other. There were two GT EL84s tubes near the pre amp tubes and I had put 2 JJ's in the other sockets. Also, on the fuses, I have some old fuses from my Peavey Classic 50 that are identical to the blown fuse except they do not say 3A specifically. Everything else is identical except that there is no amp marking AT ALL. Can I use this fuse? First: Never take the amp off of standby with no speakers plugged in. You can do much worse than blow a fuse - you can blow the output transformer. Fortunately these amps are pretty stout, so if it's working, you're ok. Second: Never use a fuse that you cannot identify. It doesn't matter if it looks identical, it could be a five or six amp fuse - you could do severe damage to your amp if that were the case and there were actually an internal problem. Go get the right fuse. Third: I'm not sure I follow what you were doing. If you want to try different output tubes, make sure you get the right thing, and make sure you plug them in the right place. It's not real clear from your description if this was the case.
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Post by edoetsch on Jun 11, 2006 19:50:20 GMT -7
OK, I'll get a properly labeled 3A fuse.
Basically there are 4 Groove Tubes EL84 tubes in the amp now. I have 2 JJ EL84 tubes and thought I'd see if changing just 2 tubes would change the sound. Probably not the best idea since the amp sounds good already.
So I used EL84's as required by the amp, but not a "matched quad".
Most likely the prob was the lack of speaker, so I'll go back to the original tubes and get a proper 3A fuse.
Any brand fuse you would recommend? Or does it matter?
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Post by foxx on Jun 11, 2006 20:06:03 GMT -7
Edoetsch, the Mazerati is a split load bias and therefore the two el84's you changed were probably okay. I don't know which of the 4 are pairs, but they can be mismatched pairs of el84's.
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Post by foxx on Jun 11, 2006 20:14:01 GMT -7
any 3A fuse will work, buy an extra of each fuse. the other is 1/2A.
I was blowing the 3A fuse when my rectifier was going bad. FYI
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