Selmer Twin Lead 50 preset

verified · 80/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The Twin Lead 50 is a hybrid amplifier from Selmer London. Two inputs feed an OC71 germanium transistor first stage, then a volume and tone network into one ECC83 triode as a gain stage; the other triode is a split-load phase inverter. A fixed-bias push-pull pair of EL506 output valves drives a 7.5 ohm speaker output, powered by a GZ34 rectifier with an IS105 diode bias supply. No feedback loop or presence control is drawn.

Tags: british, vintage, mid-wattage.

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.