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Post by Brian on Jan 28, 2013 10:11:11 GMT -7
Can you send too much/hot of a signal to the preamp side of the amp and blow tubes there?
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Post by benttop (Steve) on Jan 28, 2013 11:25:04 GMT -7
Not likely. I remember back when I was a kid, before I knew anything at all about amps, taking an old Bogen PA head and sticking its output directly in to my old Fender Pro Amp. I got a ton of saturation, but the Fender was fine with it. The Bogen didn't even complain, oddly enough.
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Post by headshrinker (Marc) on Jan 28, 2013 11:25:08 GMT -7
Never heard of a preamp tube blowing from too much signal. They compress go into distortion maybe even sound bad but it won't blow the tube as in too much electricity going through it. The voltages at that stage of amplification are really low. It might be theoretically possible but with the pickups, effects boxes, boosters etc. that we use in practice I don't think so.
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Post by headshrinker (Marc) on Jan 28, 2013 11:29:38 GMT -7
Steve: I did a similar thing in my youth. I came out of the speaker out of a brown princeton and ran the signal into the input of a Twin Reverb and also had no problems. I also was running two other 212 8 ohm cabinets off of that twin along with the internal ones taking the impedance down to something around 2 ohms and it never complained.
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Post by Brian on Jan 28, 2013 13:24:08 GMT -7
So I should probably start my diagnostics with the power tubes then...
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Post by headshrinker (Marc) on Jan 28, 2013 14:34:19 GMT -7
Starting with power tubes is always a good bet. Swap them out and see if that fixes it. If not get a known good 12AX7 and then start subbing it one at a time for each preamp tube starting at the far left. If it doesn't correct the problem put back in the old one and move to the next. If you happen to have a reverb model you can put it where the 12AT7 is to trouble shoot if you don't have a known good 12AT7. You might even prefer it there to the 12AT. I do.
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Post by doctorice on Jan 28, 2013 14:49:35 GMT -7
Brian, take a look at the troubleshooting info posted on Dr Z's website. It is very methodical and will help you isolate a problem.
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Post by Brian on Jan 29, 2013 8:53:40 GMT -7
It was one of the power tubes.
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