Gibson GA-50T

[David B]

Hi folks, I thought some of you might like a look at this.

I'd quietly been on the look out for a Gibson GA-50T for a while. Made between 1948 and 1954, it's the amp heard on most of Jim Hall and Jimmy Raney's classic recordings in the '50s and '60s (in fact they shared an amp for a time). Barney Kessel used them for many years and is the amp used on all those classic sessions for Contemporary. 25 watts into 12" and 8"speakers, in a cabinet about the same size as a Deluxe Reverb.

I purchased this early '50s example from a store in the US, receiving it last Monday. Despite it being very well packed, it took some knocks in shipping and arrived with a few issues.

The amp chassis had become completely detached from the cabinet! Fortunately it didn't cause any real damage (there's not space inside the cabinet for anything to fly around). I reglued the wooden mounts (these old Gibson cabinets are made from redwood), cleared out a few years of dust and grime and fixed the screw holes where they had been stripped out.

The electronics were beyond me, so I spent an afternoon today with Dave Piggott, getting the amp a full health check. Dave's a great swing/blues guitarist here and a real expert on Gibson and Fender amps of this era.

The speakers that came in it were not original, though both were early-'60s Gibson speakers. Both were way under-powered for this amp. They have now been replaced with new alnico Jensens - a P8R and a P12N.

On many of these old Gibson combos, the output transformer was attached to the speaker itself! For safety and easy of access, we mounted it to the cabinet and some of the crumbling old speaker wiring has been replaced and tidied up.

The rectifier had died. A new JJ GZ34S puts out a couple more volts and will give a slight volume increase (the GA-50s can be considered a little quiet). The power tubes aren't the originals but spec-correct RCAs that appear to have been in there for some time, as are the octal preamp tubes.

I haven't yet had a chance to crank the amp, but at home volume it sounds fantastic. It's a classic jazz amp tone.

[David B]

Here's Jim Hall playing through his.

[Rob MacKillop]

Wow, great find, David. I'm sure you won't part with it for a long time. Have fun together. What guitar will you be playing through it?

[wintermoon]

really nice example man! too bad about the damage, but due to the construction and frailty of these they should be packed upside down to take the load of the weight off the cab. frequently the glued on logo is either partially or completely gone, or missing the back cover.

I used one of these exclusively for about 10 years before I began playing in Hammond B-3 combos and had to go back to a Fender Twin. In that 10 year span I bought a bunch of them, sadly they no longer get used like all my old Gibson amps but still look great.
they could be had cheaply for a long time but in the last few years have skyrocketed in price.
one of the coolest looking amps ever IMO and they sound very warm.
btw, these were very expensive when introduced, I believe they were the top of the line Gibson amp before the GA-75 w/15" speaker hit the market.

enjoy that!

[vinnyv1k]

Sweet rig for sure. Sorry about the shipping damage. Bet it sounds awesome. Congrats!

[neatomic]

congrats!..classic amp!!..looks like it cleaned up nicely..enjoy

shipping is the only reason why jim hall replaced it with the polytone...too precious to take out on the road!

cheers

[999369]

Nice

my 50' BR-9 is 7-9W

[wintermoon]

p.s. in my experience these sound best plugged into the mic channel

[neatomic]

ps- gibson didnt actually make speakers..so check the speaker codes on the ones that were in there

i'm thinking oxford or cts


cheers

[wintermoon]

ps- gibson didnt actually make speakers..so check the speaker codes on the ones that were in there

i'm thinking oxford or cts


cheers

stock w/ Jensens P12, P8

[David B]

ps- gibson didnt actually make speakers..so check the speaker codes on the ones that were in there

i'm thinking oxford or cts

Hi N,

The 12" was a Gibson-branded Jensen, dating to 1961. The 8" certainly isn't the original Jensen - best guess is it was pulled from an organ or similar as a replacement.

(Note the output transformer mounted on the speaker!)

[neatomic]

8"'s 575 code makes it a heppner...speaker brand used by hammond...

cheers

[jorgemg1984]

Congrats, David! American players that go to London will now ask you for this one, instead of the DRRI

[nopedals]

One of the dumbest things I ever did was to buy a 1950 GA-30 (very similar amp), spend a bunch of dough fixing it up, and then selling it at a loss. I can't even remember why I did it. I even went back a year or two later to the ebay buyer and tried to buy it back, but it had been passed on again. A nearly perfect amp. The mic input has a ton of gain, almost like a distortion pedal.

[Klatu]

Those Jim Hall clips sound divine. Impressive. Not only does it sound beautiful, but the cabinet design is sophisticated and elegant.

[neatomic]

jim halls p90 equipped es175 through gibson ga-50 amp is iconic jazz tone!!! its a true melding of player and gear to sublime proportions!



cheers

[David B]

jim halls p90 equipped es175 through gibson ga-50 amp is iconic jazz tone!!! its a true melding of player and gear to sublime proportions!



cheers

N,

There was a '50 ES175 in the den!

[zizala]

Congratulations David B.....bet that GA-50T sounds great and it looks wonderful!

I have a pair of somewhat similar 12 x 8 amps.....a '47 GA-25 and '48 GA-30.
They're in the 15 watt range at best .....but capable of great tone and surprisingly clean sound.

My satisfaction with those two has had me half looking for just the right GA-50 over several years.
As for the original speakers, every unaltered example I've seen in my search has had a Jensen P12P and P8R.

I'm sure your choice of new speakers do their job very well!

[Alter]

These amps look fab! I 've never even heard one in person for some reason, let alone play one!

[Jabberwocky]

Is that your London bedsit, Dave? No room for a snog???

Congrats, nice amp. Glad you got a tech to put it right but you gotta look out for a flailing arm or leg that may punch a hole in 'em speaker.

[David B]

Is that your London bedsit, Dave? No room for a snog???

Ha! That's in Dave P's den/workshop/treasure cave! With two girls in the house, I barely have room for two guitars and two amps!

If you're on Facebook, Dave P has posted some nice photos of some of his collection in the 'Gibson tube amplifier users' group.

[wintermoon]

N,

There was a '50 ES175 in the den!

I see a period GA-75 sitting on it's side in the back

[citizenk74]

Nice classic amp! Congratulations, and play it in good health!

[GNAPPI]

Nice

my 50' BR-9 is 7-9W

Funny, just last week I had a BR9 on my bench. It had a nightmare AC cord wiring job, and a jury rigged pilot light. Once I replaced the line cord to start working on it I found it was blowing fuses with the rectifier tube plugged in, the caps were original and shot, but the HV / heater Xformer was OK, but the owner wanted it back thinking it wouldn't need parts, just the line cord.

I gave it back not repaired and didn't charge for the grounded line cord and my time. Cute little amp there. I was tempted to offer to buy it but figured he'd think I was trying to get it for an unreasonable price so I passed.

How's yours sound? Maybe I'll go back and make an offer anyway :-)

[Thumpalumpacus]

Sweet amp, and cool job on the rescue, brotha.