Seymour Duncan 84-40 - Lead preset

Verified · 92/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The Seymour Duncan 84-40 is a 1990 tube combo from the Santa Barbara pickup maker’s amp line, named for its four EL84s and 40 watts. A relay-switched two-channel 12AX7 preamp has a bright switch, overdrive control, treble/bass/mid and pull-switch gain boosts, with separate levels per channel. Op-amp stages drive an effects loop and reverb send and return. A 12AX7 long-tail inverter drives four fixed-bias EL84s from a silicon rectifier.

• Made in: USA
• Wattage: 40W
• Channels: 2
• Preamp tubes: 3× 12AX7
• Power tubes: 4× EL84

Tags: american, high-gain, 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.