What tubes does the Marshall 1992U use?

The Marshall 1992U uses 4× ECC83 preamp tubes and 4× EL34 power tubes.

When was the Marshall 1992U produced?

The Marshall 1992U was produced 1965–1981.

Marshall 1992U preset

Verified · 80/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The Marshall 1992 Super Bass is a 100W bass-specific amplifier based on the JMP platform, sharing the plexi-era circuit topology but voiced for bass guitar with a darker EQ balance. It was used by rock and heavy metal bassists as a powerful and relatively clean high-headroom platform.

Years produced: 1965–1981
Made in: UK
Wattage: 100W
Channels: 2
Preamp tubes: 4× ECC83
Power tubes: 4× EL34

Tags: british, vintage, bass, plexi.

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.