Marshall 20W Bass 2019 - Channel 1 preset

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

The 2019 is a 20-watt valve bass amplifier from Marshall's late-1960s small-box range, with essentially the same circuit as the Model 1917 PA and the 2022 Lead. Two input pairs feed the two halves of one ECC83, each with its own volume and tone control, mixed into an ECC83 phase inverter driving two cathode-biased EL84s off a silicon-diode supply. There is no master volume or presence, so it breaks up early when turned up.

Tags: british, vintage, bass, el84, low-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.