Hiwatt T20 - Overdrive preset

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

The Hiwatt T20 is a compact 2011-era combo with two footswitchable channels. Normal runs a 12AX7 gain stage with its own gain control; Overdrive uses a JFET clipping circuit with diode limiting and its own gain. Both share a treble, middle and bass stack with tone-shift switches, op-amp driven spring reverb and an effects loop with level control. A 12AX7 and 12AU7 drive two EL84s, switchable between pentode and triode, with a line out.

• Wattage: 20W
• Channels: 2
• Preamp tubes: 2× 12AX7, 1× 12AU7
• Power tubes: 2× EL84

Tags: british, low-wattage, clean, 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.