Gibson GA30-RVS Amp

Creating the environment for guitar modifications, with it being Jimi Hendrix’s Birthday, I say crank up the tunes as loud as you can and get to work on that Foxy Lady.

Currently I am working on a Gibson GA30-RVS Amp this is the one that was made in England by Trace Elliot, bought it at our local pawn shop and let me say, it’s heavy…in more ways than one!

The amp played marvelously when we first purchased it, but looking into changing the tubes we found that the EL-84 tube sockets were burning - after contacting the people at Gibson, we were told this is due to an inferior material used in the socket.  We found some sockets at British Audio Service right here in my back yard actually - Sugar Grove, Illinois.

I had a friend of mine - Alan - who is an electrical engineer re-wire the sockets, it was beyond my scope of taking the amp apart to actually get at the sockets.  We are still experiencing quite a bit of static (the sound of crackling  paper)  when the amp is turned on.

Currently going through the amp and checking all the connections and solder joints, as there were a lot that were un-soldered. I’ll keep you all posted on the progress as this amp is much to important to leave on the shelf, as well as my son would not let me, it is his favorite amp.  So I am “burning the midnight lamp” that Jimi spoke of on Electric Ladyland

Talk About Smoking Pot

For all you that thought this was something else, you were wrong as usual… Back to old Sunn Amp - the Volume Control was what I was really seeking and no longer available.  After going through extensive catalogs and finding the NOS part is not available, and if it was, would run us about 200.00.

I decided I would re-build the old Volume Control or Pot which is 15K and no longer available - I came to the decision after trying a 25 K and an 18 K which degraded the amp very badly - sort of like a cat screaming when he was on a hot tin roof.  I opened the sucker up, with my tube of Di Electric Silicone Grease, I smeared it across the wipers, making sure not to over lubricate as men are known to do.

I put this all back together, and being a dumb-ass and having cut it out of the amp the lead lugs I had to re-solder the lugs together, reinstall it into the amp and walla, the amp was pretty much back to normal, except a small hair line fracture glitch at the number 7th position.

Which means the wiper is worn out beyond repair.  Everything works fantastically except at 7 - The moral of the story is don’t be afraid to re-build old pots, because their quality is much better than the newer stuff and will take the re-build.

If you are a little leary of doing this yourself, please feel free to contact me at buck at bucksguitarmodifications.com and I would be more than happy to help!

Talk about Smoking Pot!

In search of Pot - Volume Pot that is

Being new to blogging, I hope I am not out of line and didn’t get all the hippies riled up with my title, nor do I want to be out of line asking for assistance, but I am in search of a pot for an old 1972 Sunn Studio lead 2-10″ speaker transistor amp.

This baby is a very cool amp, and it’s loud and clean and reminds me of the good old days! But the pot was going bad! I tried a 25k pot and a 18k pot, old stock I had laying around, not very happening if you get my meaning - blah at best actually.

I believe the pot to be a CentraLab Pot 1347230 3/8 shaft - 23-1113, it tested at 15k?

I am not sure this is the right value (going bad and all) The original pot is soldered to pc board with a ground leg acting as support for the pc board. I’ve tried various supply houses, no luck. Any help would be appreciated!

A close match to it was $150.00, not an exact match either (NOS) I only paid $120.00 for the amp at a local pawn shop! Great shopping there!