Hiwatt Custom 20 preset

Verified · 93/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The Hiwatt Custom 20 is a single-channel, low-power tube amp in Hiwatt's Custom line. An ECC83 input stage feeds a gain control and two more ECC83 stages driving a passive treble, middle and bass stack, then an effects loop with an ECC83 return buffer and master volume. An ECC81 long-tailed-pair inverter with presence drives two EL84s from a diode-rectified supply, with a line out. The brand's clean, articulate British voice at lower power.

• Made in: UK
• Wattage: 20W
• Channels: 1
• Preamp tubes: 3× ECC83, 1× ECC81
• Power tubes: 2× EL84

Tags: british, clean, low-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.