Vox Topboost Preamp preset

Verified · 85/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The Top Boost preamp is the iconic additional gain stage and tone circuit added to the Vox AC30, defining its bright, chiming character. This schematic covers the dedicated Top Boost preamp unit/module — the most recognized tonal circuit in British amplifier history.

• Years produced: 1961–present
• Made in: UK
• Channels: 1
• Preamp tubes: 1× ECC83

Known for: The Beatles, The Edge, Brian May.

Tags: british, el84, chime, top-boost, preamp.

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.