# Help...peavey classic 20 has no power.



## capnjim (Aug 19, 2011)

So I bought this amp. Like an idiot, I bought it without trying it as the seller said it worked. I get it home....nada. Only the pilot light comes on. No lights to the tube, no voltage anywhere. I guess its a dead PT. I called PV and its obviously, obsolete. Anyone know where I can get a replacement? Anything else to see if its maybe not the PT?
Thanks


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## greco (Jul 15, 2007)

Possibly a rectifier tube? ...just a guess...but I think the same thing happened to a friend's amp.

If I'm wrong, there is no loss in you having an extra rectifier tube available.

Good Luck

Cheers

Dave


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## capnjim (Aug 19, 2011)

Thanks Dave...there is no rectifier. There is zero volts coming out of the 4 wires from the PT. There is 120 going into the PT.
Would a Blues jr PT work?


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## greco (Jul 15, 2007)

So much for the rectifier tube!!...ooops! 


Mercury Magnetices has one for $150.00 USD...ouch!!
http://www.mercurymagnetics.com/pages/catalog/manufacturers/MM_peavey.htm

However, I can't seem to get the specs for their PT as a reference.

Did you see this? ...not great news..unfortunately.
http://music-electronics-forum.com/t12502/

Cheers

Dave


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## epis (Feb 25, 2012)

I did a small search and found this for you :

http://peavey.com/forum/viewtopic.php?f=19&t=27263&start=15


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## jb welder (Sep 14, 2010)

Sorry if you know this, just want to confirm before you condemn the PT:
when testing, all secondary wires should be disconnected from board, meter set to AC volts, probes connected to pair of reds, then to pair of yellows.
With 120V going to primary there should be something like 6VAC between the 2 yellows, some hundreds of VAC between reds.
Then with no power applied measure resistance across primary, should be low ohms.


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## capnjim (Aug 19, 2011)

Thanks JB. There is 0 volts. But thats good to know, 6v in the yellow, and maybe 350v from the red?
I have several old pa tube amps that run 2 6V6's. I guess one of those would work? Just hook up the 6v and 350v directly to the posts on the peavey?


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## deadear (Nov 24, 2011)

I would be getting back to the seller and tell him the situation. You might be able to return it and get a refund. It might have worked when it was parked and I don't think too many people are out to screw people.


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## capnjim (Aug 19, 2011)

I tried...he said it was working fine. It my fault. I got lost looking for it, parked illegally, ran in, grabbed the amp and left.


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## epis (Feb 25, 2012)

Hi capnjim,
don't make a mistake and mod this amp instead of simple fix.
Peavey is notorious for putting underrated transformers in these small amps. That's why they put a thermal fuse inside power transformer, just to protect it.
Most likely previous owner played this amp dimmed for long period, so PT overheated and activated thermal fuse.
An upgrade would be to install thermal switch with same temperature value instead of the fuse.
Do you really like the sound of classic 20s ?
If you do, an upgrade of power transformer would be definitely recommended. But, 350V AC on secondary would be way to much.
I would guess 250V AC should be much closer mach for 2 X EL84 in output. Even 110 Ohm cathode resistor (2 X 220 Ohm) should be changed to 150 Ohm. 
B+ voltage in classic 20s is around 330V.
Power transformers from old tube amps are most of the time with center tapped secondaries, and with higher voltages than what you need.
Also, transformer foot print is bigger then Peavey's transformer, you would need some metal work skills and tools ( and room inside the chassis ) to do it properly.
I would rather fix it then mod it. Just my 2 cents.
Cheers, Damir


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## jb welder (Sep 14, 2010)

capnjim said:


> I have several old pa tube amps that run 2 6V6's. I guess one of those would work? Just hook up the 6v and 350v directly to the posts on the peavey?


Pretty much. The current capability of the 6V heater winding is important. In this case, it needs to power 2 6V6 and 2 12AX7 types, shouldn't really be a problem unless the donor pa amp has no preamp tubes, which is not likely.
Should also mention, PT's designed for tube rectifiers will usually also have a 5V winding to power the rectifier heater. In those cases the 5V winding is often coded yellow, and the 6V winding is coded green.


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## capnjim (Aug 19, 2011)

Thanks guys....I'ts not like I'm modding the amp by choice. Its dead. This model OT does not have the thermal fuse. I wish I could fix it, but I think its shot. I hope I can find one that works. Otherwise, I'll toss the chassis and use it as a small extension cab. I got it for a good deal as I bought a bicycle with it. My daughter loves the bike so all in all its not a horrible deal.


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