Vintage Gibson amp on CL

capnjuan

Gone But Not Forgotten
Gone But Not Forgotten
Joined
Nov 29, 2006
Messages
12,952
Reaction score
4
Location
FL
Hi Pascal; that's an early-mid '50s Gibson GA40 Les Paul ... these days, it's widely considered to be the best-sounding amp Gibson ever produced. Can't tell much from the pics but the very clean ones go $1,600-$1,900 ... there are at least two GA40LPs owned by our BBers ... one of which - if he hasn't sold it yet [he's been talking about it] - is a later model with black over tweed cosmetics (Seen here, page 2; see also page 4) but the same circuit as the CL model; 2X5879 (channel 1 and 2 preamps), 1X6SQ7 (tremolo oscillator), 1X0725 (phase inverter/driver), 2X6V6, and a 5Y3 rectifier.

I think the secrets of the amp's fine tone are (1) 5879s in the preamps; the 5879 is a pentode, not a twin-triode like a 12AX7 ... it's built like an output tube and they produce a hot, smokey tone. My GA20T that you listened to ... it has a 5879 in channel 2. (2) an output transformer that is larger than those found on both Gibson 'student' amps with lower 'GA' numbers and the GA78/79/83/90-series 'stereo' amps. (3) A post-phase inverter master volume control shown in the blue circle below:

ga40tone.jpg



The Master Volume means that the 5879s can be run to near-distortion and then still have the chance to modulate volume just ahead of the output tube. PPIMV not adopted by most other mfrs until the mid/late '60s. Assuming the CL amp is in average to good condition, it's a reasonable price.

On that other Gibson amp you posted last week ... the black one with a Fender badge, I replied to your post and I think it's a GA30. The CL post was messy; the seller didn't know anything about it; wanted people to tell him what it was so he could figure out what it was worth ... anyway, I sent him an offer on it ... I don't expect to hear back. Cheers! John
 

mad dog

Gone But Not Forgotten
Gone But Not Forgotten
Joined
Feb 1, 2007
Messages
1,269
Reaction score
240
Location
Montclair, NJ
Pascal:

I'm the guy with the later GA40 les paul amp. It has "experienced" cosmetics, but otherworldly tones. If you can do so, that mid-50s amp is worth checking out. Most are held back by their stock speakers. If not ripped up or just tired, the vintage alnicos usually don't let you hear what the amp can do. A set of NOS 6v6 and a more efficient speaker brings out that hot, swampy vibe. If you like tweed deluxes, you love this amp. Same wattage, but a darker, hotter sound.
MD
 

bluesypicky

Enlightened Member
Joined
Sep 8, 2009
Messages
7,763
Reaction score
394
Location
Jupiter, FL.
Small world isn't it MD?
Thanks to both for your answers, wish it were closer, but definitely tempting....
 
Top