What tubes does the Gibson GA-83S Stereo-Vib - Channel I use?

The Gibson GA-83S Stereo-Vib - Channel I uses 4× 6BQ5 power tubes.

When was the Gibson GA-83S Stereo-Vib - Channel I produced?

The Gibson GA-83S Stereo-Vib - Channel I was produced 1959–1961.

Gibson GA-83S Stereo-Vib - Channel I preset

Verified · 89/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The GA-83S Stereo-Vib is a 1959 Gibson stereo amplifier whose main chassis runs two independent output channels. Each side has half of a 12AU7, a 6CG7 phase inverter and half of a second 6CG7 as a driver, feeding its own push-pull pair of 6BQ5 (EL84) tubes and output transformer. A 12AX7 oscillator supplies the vibrato, with depth and rate controls in the preamp, and a GZ34 rectifier powers both sides and the separate preamp.

Years produced: 1959–1961
Made in: USA
Channels: 2
Power tubes: 4× 6BQ5

Tags: american, vintage, clean, stereo, vibrato, el84.

Schematic-derived preset files for the Neural DSP Quad Cortex and 16 Fractal and Line 6 modelers: Axe-Fx II/XL/XL+, Axe-Fx III, FM3, FM9, and the full Helix family (Floor, LT, Rack, HX Stomp, HX Stomp XL, Native).

Gridleak extracts amp parameters from original circuit schematics using AI vision — component values, gain staging, tone stack topology, tube types — then generates native preset files for every supported modeler. Every extraction is scored 0–100 and the score is published.