Sound City L/B 50 Plus - Brilliant preset

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

The Sound City 50 Plus is a 50-watt British valve head. Brilliant and Normal channels each take two inputs, their own ECC83 half and their own volume, then two more ECC83s carry active bass, middle and treble controls built into the triode stages, with a Gain control. An ECC81 long-tail phase inverter drives two EL34s in fixed bias from a silicon bridge supply with standby, with 4/8/16-ohm and 100 V line outputs.

• Made in: UK
• Wattage: 50W
• Channels: 2
• Preamp tubes: 3× ECC83, 1× ECC81
• Power tubes: 2× EL34

Tags: british, vintage, crunch, mid-wattage, two-channel.

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.