This was on the bench this morning and I took some beauty pics. This amp bears a fair electronic resemblance to the Fender Princeton (AA964 model) twin 12AX7s, twin 6V6s, 5Y3 rectifier, Class A/B push-pull, cathode-biased, rated at 15 watts. This amp is fitted with a 10" Weber 10A125 on a new 9-ply Baltic birch baffleboard; formerly had a Jensen P10R that now has a happy home with one of our BB broz. Logo is aftermarket plastic held in place with brads.
These amps were sold with slightly lighter and slightly darker tolex; this is the lighter tolex. Unlike Fender's cotton tweed covering, this covering is sheet vinyl with patterned cotton fabric bonded to the back; more like the old sticky tablecloths. These amps commonly have stains caused by the interaction of the covering and the water in the glue used to adhere it; this amp has almost none of the characteristic orange staining.
View of the control panel, right to left; volume, tone, tremolo speed and tremolo intensity:
Footswitch made of a block of solid mahogany; paint removed and FS refinished:
View of the chassis:
Pre-amp and tremolo sections, pretty crowded for pulling/replacing resistors and capacitors. Today's work included change out three Orange Drop coupling caps for Sprague 150s (the three little yellow guys), refreshing the preamp cathode caps and resistors, and re-tensioning the rectifier socket:
Power supply and output tubes. The configuration of the blue caps on the left is the work-around in this amp for replacing 'cigar-style' paper capacitors; the 'tweed' generation Gibsons did not use multi-section can caps - 30uf for the B+, 30uf for the screens, and 22uf for the preamp. The blue/dark blue cap in the foreground is the cathode cap in parallel with the cathode resistor:
The GA18 has been completely refurbished; it was in good condition when i got it with stock parts and it sounded pretty good but I was interested in hearing what the original design would sound like with fresh and/or better-grade parts, fresh tubes, and a new speaker. The sound is quintessential 'tweed-era'; throaty, meaty, thickish, compressed, chimey, and syrupy; the amp starts to break up at 4/5 on the volume into the gravelly, crunchy thing. It isn't Fender sound, it's Gibson sound ... no matter what the Fenderistas say, an amp doesn't have to sound like a Fender to have great sound. CJ
These amps were sold with slightly lighter and slightly darker tolex; this is the lighter tolex. Unlike Fender's cotton tweed covering, this covering is sheet vinyl with patterned cotton fabric bonded to the back; more like the old sticky tablecloths. These amps commonly have stains caused by the interaction of the covering and the water in the glue used to adhere it; this amp has almost none of the characteristic orange staining.
View of the control panel, right to left; volume, tone, tremolo speed and tremolo intensity:
Footswitch made of a block of solid mahogany; paint removed and FS refinished:
View of the chassis:
Pre-amp and tremolo sections, pretty crowded for pulling/replacing resistors and capacitors. Today's work included change out three Orange Drop coupling caps for Sprague 150s (the three little yellow guys), refreshing the preamp cathode caps and resistors, and re-tensioning the rectifier socket:
Power supply and output tubes. The configuration of the blue caps on the left is the work-around in this amp for replacing 'cigar-style' paper capacitors; the 'tweed' generation Gibsons did not use multi-section can caps - 30uf for the B+, 30uf for the screens, and 22uf for the preamp. The blue/dark blue cap in the foreground is the cathode cap in parallel with the cathode resistor:
The GA18 has been completely refurbished; it was in good condition when i got it with stock parts and it sounded pretty good but I was interested in hearing what the original design would sound like with fresh and/or better-grade parts, fresh tubes, and a new speaker. The sound is quintessential 'tweed-era'; throaty, meaty, thickish, compressed, chimey, and syrupy; the amp starts to break up at 4/5 on the volume into the gravelly, crunchy thing. It isn't Fender sound, it's Gibson sound ... no matter what the Fenderistas say, an amp doesn't have to sound like a Fender to have great sound. CJ