Sound City 120 Slave preset

Verified · 88/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The Sound City 120 Watt Slave is a power amplifier with no tone controls, driven from another amp or preamp to add output and drive extra cabinets. A transformer-coupled input feeds a Volume control and an ECC83 stage with a Set Gain trim, then an ECC81 long-tail phase inverter with negative feedback from the output. Six fixed-bias EL34s with a Set Bias trim run from a BY127 silicon bridge with standby. A transistor buffer provides a Slave Output to chain further amps; outputs cover 4/8/16 ohms and a 100 V line.

• Made in: UK
• Wattage: 120W
• Channels: 1
• Preamp tubes: 1× ECC83, 1× ECC81
• Power tubes: 6× EL34

Tags: british, vintage, power-amp, high-wattage.

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.