Ampeg V2 Head that needs something....

[skellyellison]

I have an old Ampeg V2 head from the 70's and I just put new tubes in it and I am not getting any power to it. It had the original 7027A's in it and one of them had burnt out (I called it a Supernova). Back a few years ago some friends had hooked it up and accidentally plugged a power source into the input of it and caused the tube to burn out. Anyhow, I haven't used the head since that happened thinking tubes would be extremely hard to find for it. I read recently that the amp will use 6L6GC's and I bought a pair of Ruby's. I installed the tubes and plugged it in and of course had a speaker of the correct ohmage also had my guitar plugged in. No power light or anything when I flipped the switch. I looked inside and it appears flawless, nothing looks burned out of and all internal fuses look perfectly fine. The back fuse is fine as well. Everything looks pristine and the head itself has always been taken very good care of. Anyone have any ideas what might have happened and what I should check?

[drlowlow]

isolate as much of the circuitry as possible by taking all the tubes out, even the rectifier. if you don't have one, buy, borrow or, steal (not from someone else on the forum) a DMM. with the chassis out of the cabinet plug it in (no power tubes no worry about having the speaker hooked up) check at the two sides of the switches and figure out where power is going and where it stops going. probably an open somewhere (might be the transformer), if it was a short you would have blown fuses. stay safe and hopefully it is something easy to fix.

[skellyellison]

will do....

I actually have a brother in law who is an electronic technician and I think I'd feel a bit safer with him doing the check. I'd end up looking like ...I stuck my finger in a lightsocket probably literally. I appreciate the advice and I will keep the fact of not having the power tubes in it in mind because I definately won't be lugging a cab over to his house when I take it. My guess is it would be the transformer. It's been so long since it happened any scent of anything fried has long diminished. It's had to get something internally that can't be seen from above or peering into the chassis with it unbolted and pulled out. Gotta hand it to Ampeg though, it does have a complete schematic on the reverb plate so that should help trace the problem. Wish me luck! It's a nice amp!

[Enzo]

While possible, the transformer is about the last thing on th list of suspects.

This is a tube amp. NEVER NEVER NEVER run a tube amp without a speaker or similar load. DO that and you would need a transformer.

If the power tubes are out, then it would be safe, but you can't determine if the amp works without power tubes. Onve you have it powering up again, you will have to put tubes in it to proceed.

All tubes for that amp are readily available.

[skellyellison]

Thanks for the replies...

I still haven't got it working...

I am about to do the tests you have recommended. My bro-in-law hasn't had time to check it out so I will run my tester over and see if I can see where the power is or isn't getting to. And yes, I will remove the power tubes. haha I know about the load issues and such, my bandmates several years ago were who messed it up while I was out of the practice room. Back then I assumed they just burned out the tubes by hooking a powered PA output (only about 150 SS watts) into it. When it happened it really just supernova'd a power tube and I assumed the head only needed a new pair of tubes. That's what I call it when one lights up real bright then goes kapuut. haha I ended up using another power amp back then and never set aside time to fix this one. Just stored it away until recently when I realized just how darn good it would make my rig sound in my current band.

I have some brand new Ruby Tubes to install into it. They are 6L6GC's. I'd like for you all to confirm if those will work in an un-modified Ampeg V2 from '75 before I go further into installing them. I had read they will work on a Tube Amp forum and through my searches for replacements is how I came across that info also.

Also, I will do my best to try to take a picture of the schematic of the amp if I can get a good clear shot of it I will post it as well. Might even take a good picture of the inside of it and you all can tell me more details about what to check and where to check at...

Anyhow, thanks for all of your advice and I will post more info as I acquire it and I will check for your responses as well.

[skellyellison]

Actually cancel all further thought folks...

I just ran the tester over it and oh how simple it was!!!

There's a ground wire that runs from the fuse over to the power cord input and somehow it had disappeared. It was obvious a wire had been there between the two posts as there was still remnants of a wire on each post. I cleaned it up and found a wire of the exact gauge of the leftover piece. I soldered the new wire between them and I now have one mean sounding mint-condish...1975 Ampeg V2 head with brand new tubes!! Loving it!

I really appreciate both of you for replying to my message. I own a music store and had no idea about tube amps. That's about all I don't know how to work on. Anyhow, if you fellas ever need anything don't hesitate to ask.



One thing I will never do again, and that's allow someone else to hook my rig up!!! Unless I get THAT successful and someone who knows my rig better than me is pluggin wires. I assume I'll always have to settle on my good ole self rather than the latter. haha