Question:
Well, ive owned a 70's Peavey Classic for many years, and ive tried to sell it several times, but i cant get enough money for it to be worth it. So ive been thinking about fixing it up for myself, since i dont have another tube amp. Its 100watt, 2x12" amp with 4 6L6 tubes.
It hasnt been working for about 2 years now. It powers on fine and all the tubes light up. When i plug my guitar into it, it barely produces any sound. When i jiggle the fuse holder on the knob panel, the sound becomes louder and sounds clearer. so, naturally i figure it has probably some bad connections. What do i need to do to check/fix this... open the case and look for bad soldering points??
Even before the sound was cutting out, the amp still wasnt at full potential. The wouldnt get very loud, and didnt sound that great. Do you think the speakers(they are very old looking) are to blame, or the tubes? Or should i just replace both. I am on a very tight budget though. Any help is much appreciated, ill try to get pictures up tonight or tomorrow. thanks
Answer:
First off, BE CAREFULL.
If you aren't very electronics-savy I wouldn't recomend messing around with to much, however, if I were you I'd pull the tubes and check the sockets for corosion WHEN THE POWER IS OFF. You can also check the speakers themselves by hooking up an alternative sound source and checking and listening to them.
I might be wrong here, so you should probably wait for Maj. Tom or Rainer to respond.
Answer:
I'd say go ahead and get the schematic from Peavey if you havn't already. Open it up and see if you can see anything wrong (bad/loose solder, wire, or parts)...then work from there. Make small steps.
A few things to look at: The power tubes. How old are they? The filter caps. How do they look? Any buldges or leaks?
Answer:
where are the filter caps?
Answer:
oh, and make sure that all of the capacitors are drained before you start working on the amp. caps can carry lethal voltages years after the equipment is unplugged... i'm sure someone can give you better instruction to do this. just don't go poking around back there till you know its safe
and a multimeter would probably come in handy for tracking down your problem (around $20 at radioshack or sears for a digital one)...
Answer:
i have some multimeters back at school, but im home for several weeks. how can i drain the caps? short them, or ground them or what?
Answer:
Originally Posted by SenorPapaCabasa i have some multimeters back at school, but im home for several weeks. how can i drain the caps? short them, or ground them or what?
ok, i snapped a few shots of the tubes. there was some real discoloration on the top of the all the tops(side closest to the prongs), and some other spots that looked like burns, i took a picture of a tube and circled these areas.
Answer:
Originally Posted by BlessedNinja First off, BE CAREFULL.
You can also check the speakers themselves by hooking up an alternative sound source and checking and listening to them.
would i just need to unplug the speakers from the amps output jack and plug them into whatever other source im testing with? what would be good to use... another amp, a stereo...?
i know i have lots of questions, thanks for everyones help
Answer:
can you get a pic of the inside of the amp?
Answer:
Originally Posted by SenorPapaCabasa would i just need to unplug the speakers from the amps output jack and plug them into whatever other source im testing with? what would be good to use... another amp, a stereo...?
i know i have lots of questions, thanks for everyones help
i guess that it would be OK to plug into something to test it. something to keep in mind is speaker impendence. if you plug it into something else that is expecting a 16ohm load and you give it a 8ohm load, you could very well blow the output transformer of the amp. i'm guessing that the speakers wouldn't be a problem... could be, but not likely at all. even 'blown' speakers can fart.
Originally Posted by SenorPapaCabasa ok, i snapped a few shots of the tubes. there was some real discoloration on the top of the all the tops(side closest to the prongs), and some other spots that looked like burns, i took a picture of a tube and circled these areas.
to me, it looks like your tubes went out. my amp hasn't gone through that yet, and i'm guessing that is what happened... i've also heard that when one tube goes out, it wears down the others a lot faster... resulting in you getting all new tubes. i'm guessing that those are dead now... either they simply passed on and are the problem themselves, or there is another problem with the amp that caused these tubes to go out. i'm not an expert on tube amps, so i'm sure someones got a better idea here... but thats what it looks like to me.
Originally Posted by SenorPapaCabasa i have some multimeters back at school, but im home for several weeks. how can i drain the caps? short them, or ground them or what?
draining caps? hmm... shorting them -connecting a lead to both the positive and negative of the cap will drain them... give them a little while to (10 sec or so). i know that there's another way to drain them through the amp, but i don't know how to do it.
Answer:
after reading up on it a little more, im pretty sure its either a bad cap or bad tubes, or very likely both. The third tube is really loose from its base, when i unplug it, i can wiggle the glass part around alot, without any effort... none of the others are loose like that, cant be good. ill get a pick of the inside asap.
Answer:
Some tubes do that anyways, wiggle. In any case, change em all. that's a frickin' old amp, dude. lol.

Case
Answer:
indeed it is old. i can only image how bad the circuit must be if its all original. i have no idea how old the tubes are, but they are mesa's. but they are at least 3 years old, thats how long ive owned it. and hardly played it.
Answer:
gut shots. the last one is with the power on.
Answer:
Well, i took the old-timer to a guy who has done some bass repairs for me in the past. He is supposed to tell me whats wrong and give me a quote monday, for free