Marshall Stereo Chorus Reverb 8240 - Boost preset

Verified · 86/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The 8240 is a 2×40-watt stereo chorus combo from Marshall's early-1990s Valvestate range, a smaller sibling of the 8280. A footswitchable Clean channel has gain with a Clean/Crunch switch, its own treble, middle and bass and LED clipping; the Overdrive channel adds a two-mode gain stage feeding a single ECC83, with its own EQ and volume. Spring reverb, stereo chorus, a series effects loop and transistor stereo power amps complete it.

• Made in: UK
• Wattage: 80W
• Channels: 2
• Preamp tubes: 1× ECC83

Tags: british, hybrid, stereo, clean, crunch, reverb, two-channel.

Schematic-derived preset files for the Neural DSP Quad Cortex and 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.