Ashdown ABM 500 preset

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

The ABM 500 is Ashdown's hybrid bass head of around 2000. Hi and lo sensitivity inputs feed a JFET buffer and op-amp gain, then one ECC83 whose clean and grind paths are blended by an Input Mix control. A Shape switch, a sub-harmonic generator with its own level, and a seven-band active EQ (45 Hz to 5 kHz, with bass, middle and treble at the ends) can each be switched in, ahead of an effects loop, DI and three pairs of MOSFET outputs rated 400/500 watts.

• Made in: UK
• Wattage: 500W
• Channels: 1
• Preamp tubes: 1× ECC83

Tags: british, bass, hybrid, 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.