Vintage Mystery Gibson Amp Overview, Repair and Demo

A customer brought me this puzzler the other day. It was sounding nasty. Very crackly, very sick. We'll investigate what's wrong with it and also try to figure out exactly what it is in the process.

[@charlesshaw9090]

Another excellent video! The detail really helps and the results speak for themselves. Great!

[@McSynth]

I love your videos. I've learned more about tube amps from you than 30 odd years as a bassist. Keep up the great work ! :-)

[@Zelleram55]

Cool video I never paid any attention to the old Gibson amps until I started watching your channel. They sound good when your done with them. Thanks.

[@TheGuitologist]

Thanks for the comment. That's nice to hear that other people also agree these are great little amps that deserve their due.

[@redfishbum]

Great intro line!!LOL. Great video as usual. Really like the guitar playing and sound after the inspection/repair. Thanks!

[@TheGuitologist]

+redfishbum Thanks man! Yeah, the trusty old GA-20s really deliver the goods don't they!

[@redfishbum]

Hell yes.....that amp delivers

[@ltousig]

Awsome video, thanks for sharing your expertise. The covering on my GA18 looks like tweed; the stuff in the handle matches the covering on my amp. I think you're right that yours was recovered.

[@tonypotter1937]

Great video Rob. That Amplifier sounds great! Keep the vids coming, I'm learning a huge amount from them. I have a 1978 fender twin with the dreaded ultra linear output, which I'm going to try modding soon. Tony, in the UK.

[@vmat1000]

Geeez, i love these repair and demo vids, man. Thanx, Brad. Another 'one that got away' was a Gibson amp that went with a lap steel i borrowed for about 6 months from a guy i grew up with when i first started playing as a 15 year old in 'late '72. It was his his uncles and i couldn't buy it without the lap steel. This was before i knew of David Lindley ;( Sprayed on white finish with a bar across the speaker opening with a gold G in the middle. Student model like with just a tome and vol but hit that with an LPB-1 and you got a screamer!! In nearly 30 years of looking, i haven't seen this amp again anywhere.

[@chokkan7]

Great work, as usual, Brad...keep it up.

[@TheGuitologist]

+chokkan7 Thanks a lot. Appreciate you watching.

[@aletotheking]

Just discovered your channel and LOVE it! Is there a particular Gibson amp that you prefer? I'd like to buy a used Gibson combo because old Supros and Magnatones are so expensive now they started to make them again.

[@sangandongo]

Figured it out. It's a 1960 retolexed GA-20 Tweed cab with that '51 chassis. There's one on Reverb right now.

[@utubehound69]

Nice tones thru that step-Son amp.

[@jonnybeck6723]

What a great tone!

[@ianbanhamamprepair9457]

What a great sounding amp.

[@danielwoll6917]

Thanks for the interesting videos. I love seeing the old stuff work. I have a question. my voxvt40x fell over backwards and now it won't power up. where do I start to figure this out. I don't have the 100 bucks the local guy wants so I guess I'm hoping it's something I can handle. thanks again for the vids.Daniel

[@bucyruserie1211]

Shame what happened to that amp over the years, but you were right..... that thing screams! Very cool.

[@jameswilson3554]

Sounds awesome.. I'm looking for a back cover for a gibsonette G8 amplifier..any idea where to find one ?..2thumbs up great video..

[@scotttracey3748]

Nice repair job on the amp sounds great, l have a 57 Gibson 95 watts two tone combo amp model 65790 GA55V that l'm selling on Kijiji been sitting in my warm storage room for 25 yrs l was shocked when l plug it in it still seems to works okay, l wish i could afford someone with your knowledge to make sure it's functioning properly.

[@bernhardnizynski4403]

Which company built the old tweed amplifiers for Gibson?

[@Robmgwan]

Brilliant video man... (UK)

[@TheGuitologist]

Thanks a lot, Rob. I appreciate the comment.

[@pharmerdavid1432]

I appears to be a GA6 "Lancer", which used push-pull 6V6s - a cross between the 5D3/5E3 Tweed Deluxe circuits (got that info from "garage amps).. It's supposedly almost identical to the GA15 "Titan", except using a 12" speaker instead of the Titan's 10" speaker. I have a few 6V6 tweed Gibson amps, but not the GA6 and GA15. I want both, but they are rare, and therefore expensive. Then too, after watching another video by the Guitologist, a GA-19 Falcon is on my list too...

[@sangandongo]

I was torn at first on whether the cover was original or not. The crackling under the handle would have been due to compression on that rough tolex. However, the amp cabinet appears to me to be an early 50s style brown amp. It's just not right. The cream tolex reminds me too much of Fender rough blonde.

[@raymondheath7668]

What's the weirdest critter you have found in an amp case?

[@A.WebbAndFriends]

I have a mysterious tube amp problem that maybe you can look into regarding the SUPRO 1650RT ROYAL REVERB (reissue). I am having tube Rectifier issues that is making me very frustrated and costing me money. FIRSTLY you should know there are two (2) models within the 1650RT line. A 35/45/60 rectifier config knob, and a 35/60 toggle switch line. I have the 35/60 watt toggle switch version. Bought mine USED and out of warranty. Both versions have DUAL RECTIFIERS. the 60 watt (AB) mode uses a digital rectifier that I have to crank up to 3/4 and I do get some gain, but the 35 watt (A) mode uses a tube rectifier - The CLEANS sound angelic - really nice but absolutely no gain in the 35 watt mode. I bought TWO new rectifier tube and both tubes did Not fire up, just dead in the water which lead me to believe the TUBE RECTIFIER section of this amp is down. Any way for me to test it? Maybe something simple in the amp is unplugged or unjacked? I really could use your input OR ANYONE READING THIS feel free to chime-in. Thanks in advance - I looked everywhere for any forums on the subject - but nothing. HELP !!

[@cawfeedawg]

Is it a gibson falcon?

[@geraldhewett6893]

I have a 1972 Gibson GA20 when I turn it on there's a buzzing sound a humming sound can anyone tell me what to look for?

[@geraldhewett6893]

That 7I2 Gibson Ga 20th a solid state

[@tanyet]

Looks a bit like a Crest GA20. I used to have. I much prefer the early 50's GA20 though.

[@Hoss4Blues]

That cabinet looks just like my Gibson Falcon.

[@brittisaacrossman]

Wow, that little thing really chunks!

[@TheGuitologist]

+Britt Rossman 50s Gibsons, man! I'm tellin' ya!

[@mro2112]

Weber speaker made in Kokomo, IN. Company still owned by the son, TA Weber. Endorsed by Clapton (for his Fender combo), and everyone from Pete Townsend to Gaslight Anthem. Made 20 miles from me, and yes, he's online.

[@TheGuitologist]

+mro2112 I know. I used to live in Evansville.

[@LPCustom3]

Looks like It's a late 1961 GA-20 "Crest" cabinet.

[@TheGuitologist]

'61 would have still been the tweed. The handle is a giveaway for tweed era. It's def a mutt though.

[@LPCustom3]

With Gibson during that time period there were always times where covering and cosmetics lapped over from one period to the other.. I have a nice tweed 1960 GA-20 "Crest" that's in great shape, probably 8.5-9 out of 10. I've worked on a number of old late 50's/early Sixties Gibson amps.. As I'm sure you have as well..

[@waynegram8907]

Root Cause was bad screen and plate resistors on both power tubes

[@sagephillip6119]

cool

[@BenPrevo]

Don't like the neutral going to that fuse

[@TheGuitologist]

+Ben Prevo That is the way these things are wired originally. One side goes to switch, the other goes to fuse. You're right though, ideally they need to go hot wire (black) to fuse, then in series to switch, then PT, which the white goes to other side of PT.

[@BenPrevo]

+The Guitologist When I rewire -- I send the hot to the fuse tip then tip collar to switch to xfrmer -- neutral straight to other side of xfrmer -- take out 'death' cap and ground the green to chassis

[@joesimon2018]

The key a lot for times with these old amps is to get the tired 60 year old speaker out of there and replace it with a new one. Save the original for the collectors. But for playing a lot of times they're just tired.

[@TheGuitologist]

I completely disagree. Old speakers can be like old guitar tops, they are broken in from decades of reproducing the frequencies the amp is capable of producing, the cones tend to have less doping and are far less stiff. Nothing beats a vintage Jensen Concert Series AlNiCo speaker for these types of amps.

[@TheGuitologist]

If the speaker is bad - rubbing voice coil, degraded cone, etc. - that is a different story.

[@joesimon2018]

The Guitologist My favorite speakers tend to be ceramics like a Jensen C12N. For some reason I like ceramics for speakers and alnico for pickups. Anyway I find a lot of old amps improve a lot with a speaker upgrade. A lot of older companies put inefficient cheap speakers in amps to save money. I've also reconed Jensens and they seen livelier louder and more alive than original ones. I've assumed the paper just loses stiffness and strength over time.

[@TheGuitologist]

I guess it would depend on what style of guitar playing you're into. It's all a matter of taste, but generally, the problem with some speakers is they can tend not to break up at all and they're not nearly as responsive to dynamics. There's no roll off at low volumes. But it's a case by case basis. I'm always open to being wrong.