Maestro GA-78RV Stereo 30 - Channel 1 preset

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

The Maestro GA-78RV Stereo 30 is a Gibson-built stereo tube amp with two complete channels, each with 6EU7 gain stages, its own volume, bass and treble, and half of a shared 12AU7A cathodyne driving a push-pull pair of 6BQ5 (EL84) tubes, about 30 watts in all. A 7199 runs the footswitchable reverb, a stereo/mono switch links the channels, and the power supply sits on a separate chassis.

• Made in: USA
• Wattage: 30W
• Channels: 2
• Preamp tubes: 3× 6EU7, 1× 7199, 1× 12AU7A
• Power tubes: 4× 6BQ5

Tags: american, vintage, stereo, el84, reverb, tremolo.

Schematic-derived preset files for 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.