Author Topic: Gonna get me a '58 two-tone GA-40 (Read 9176 times)

Tinus · « **on:** March 14, 2006, 12:56:33 AM »

Hey there,

In just a few days I'll pick up a '58 Gibson GA-40 Les Paul amp which I'll swap/exchange with the owner for the Rickenbacker 330-12 I am selling. It's completely original (incl original Jensen P12 alnico 5, dust cover and wooden footswitch) and allegedly in good shape overall and fully functional. I can hardly wait to plug in my Casino and go for it :P .

These are fun amps with serious gig potential, at least for my playing style. It has a 14-16W poweramp (2x6V6) with a 12AX7 phase splitter and a 5Y3 rectifier and oddball valves for the preamp (5879's anyone?) and tremolo (6SQ7). Twin channel / Four inputs, master tone, one volume per channel and rate&depth for the tremolo. Luckily the oddball valves are in stock with Watford Valves and other dealers. Allegedly these amps sound darker than comparable Fenders of the era (Tweed Princetons, Deluxes) with a very warm compressed overdrive with great mid detail from volume 4 and up.

My plan with this amp is to have it checked by a friend who is an amp-tech (48 year old filter caps might not withstand regular playing very long).I'll also get replacement NOS valves. If I decide to gig it regularly I will get a modern replacement speaker as I wouldn't want to mess up the original Jensen. Ultimately I plan to study some and invest in proper tooling so I can service this amp myself. Then my next step would be to build a replica from scratch.

I'll keep y`all posted on this, while I wait inpatiently 'till Sunday. If it's any good in this current state I'll see if I can record a sound clip with my BKP90 equipped Casino.

Searcher · « **Reply #1 on:** March 14, 2006, 01:34:07 AM »

Cool! I'll be interested to hear how it sounds. :)

tewboss · « **Reply #2 on:** March 14, 2006, 01:36:15 AM »

I know that Tube Amp Doctor sells unusual valves, so check out their site.

Tinus · « **Reply #3 on:** March 15, 2006, 12:22:02 AM »

Thx Tewboss, I already did that but they don't seem to stock them all. Might still drop them a line to ask them 'though.

_tom_ · « **Reply #4 on:** March 15, 2006, 01:19:50 PM »

That looks cool, looks like its had some usage which looks great :D Hopefully it sounds great aswell.

Tinus · « **Reply #5 on:** March 15, 2006, 02:44:14 PM »

Quote from: _tom_

That looks cool, looks like its had some usage which looks great :D Hopefully it sounds great aswell.

Well I hope I look this good when I'm 48 years old

Actually I think the tolex and tweed are in quite good nick and original speaker and components is rare. I saw a lot of Gibson amps of this age offered that were in hellish shape or badly restored, most with replacement speakers and issues like malfunctions in tremolo etc. So I'm very VERY curious as to how it'll sound :D

Underground_Player · « **Reply #6 on:** March 15, 2006, 07:31:30 PM »

I heard someone playing a GA-15 at the Matamp factory and it made his Tele sound like a big ES-345 or something. He was so darn good though some of the sound would have been in his fingers, but still - instant classic warm jazz sound :D
He was running it at quite low levels so I never heard anything close to overdrive; from the clean sound I got the feeling it would've been great though.

The amazing Phil · « **Reply #7 on:** March 15, 2006, 08:00:06 PM »

That's a classy looking amp, I bet it'll be awesome.

38thBeatle · « **Reply #8 on:** March 15, 2006, 11:37:14 PM »

Ditto Phil's comments above.

Tinus · « **Reply #9 on:** March 16, 2006, 12:04:44 PM »

Quote from: The amazing Phil

That's a classy looking amp, I bet it'll be awesome.

Well I sure hope so! Off course with an amp of this age all sorts of things could have gone wrong, like faulty valves, leaking capacitors, speaker and tranny failure etc. However because it's in working order I should be able to assess what it's capable of. According to the seller (who claims to be the second owner) the 1st owner only used it at very low levels in a Hawaii orchestra which is why it's in good shape both technically as in appearance.

For you trainspotters out there: George Harrison used this one for the Cavern gigs and the first album before going VOX. Just one more reason to get a nice Gretsch Duo Jet later to go with this amp :D. Also I think I saw one on stage with Johnny Cash in the Walk the Line movie, but that might well have been a similar Two-Tone Gibson amp of the era.

All I can say for now: waiting s%@cks, I literally have trouble sleeping because I'm so anxious to hear it :guitar4:

Tinus · « **Reply #10 on:** March 16, 2006, 12:15:58 PM »

Well I got my amp, and although it needs some work it sure sounds excellent. It has a very deep and warm tone without being dull. The onset of overdrive is very gradual, at first the sound only thickens up before breaking. It sounds best with my Riviera and booster pedal (Banzai new Rising Sun II) adding some grit if I need it. Can't post any clips yet (sold my PXR-4) but I will record some in the following weeks when I can lay my hands om some adequate gear.

One interesting note is that my amp is not a GA40 but a GA20T (also from 1958). The only difference between the two is that the GA20T has a 12AY7 for the (lower gain) instrument input, while the GA40 has a 5879.

Tinus · « **Reply #11 on:** March 21, 2006, 11:02:35 PM »

Some pictures:

Tinus · « **Reply #12 on:** March 21, 2006, 11:04:12 PM »

And some more:

Tinus · « **Reply #13 on:** March 21, 2006, 11:04:46 PM »

The main problem now is hum. My guess is the filter caps are deteriorated after almost 50 years. Some caps look like they've leaked wax so they are probably almost done. Luckily I met an amp tech while I was travelling with my amp and he agreed to have a look at it with me present, so that should be a nice field day.

The amazing Phil · « **Reply #14 on:** March 21, 2006, 11:05:45 PM »

I've always been tempted to splash out on a vintage amp myself, these pictures are bad for one's GAS don't ya know old boy.