Vox Concert 100 preset

Close · 77/100 confidence. Most values readable. Minor gaps filled by inference from similar circuits.

The Concert 100 is a 100-watt Vox valve head of the 1980s. Two inputs feed a cascade of triode gain stages with a gain control and a passive treble, middle and bass tone stack, then a master volume and a long-tailed-pair phase inverter. Four fixed-bias output pentodes, with adjustable negative bias, drive the output transformer from a solid-state bridge rectifier. The hand-made drawing does not name the valve types.

Tags: british, 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.