Maestro GA-78RV Stereo 30 - Channel 2 preset

Close · 78/100 confidence. Most values readable. Minor gaps filled by inference from similar circuits.

Maestro was a brand name used by the Gibson-affiliated CMI (Chicago Musical Instruments) for effects and amplifiers during the 1960s. The GA-78RV Stereo 30 was a stereo amplifier with onboard reverb, representing the technological experimentation of the era as manufacturers explored stereo and spatial audio for guitar. Maestro equipment is collected for its historical significance and quirky sonic character.

• Years produced: 1960s
• Made in: USA
• Wattage: 30W
• Channels: 2

Tags: american, vintage.

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.