Vox AC4 preset

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

The AC4 is Vox's small early-1960s valve amp. Two inputs feed an EF86 pentode, then a 1M Volume and a 1M Tone control ahead of a single EL84 running single-ended in Class A into an 8-inch speaker. One half of a 12AX7 is a phase-shift tremolo oscillator with a depth control and an on/off footswitch, the other half modulates the signal, and an EZ80 valve rectifier supplies the high voltage. The same drawing covers the Domino Normal.

• Introduced: 1958
• Made in: UK
• Wattage: 4W
• Channels: 1
• Preamp tubes: 1× EF86, 1× 12AX7
• Power tubes: 1× EL84

Tags: british, vintage, el84, class-a, low-wattage, practice.

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.