Hiwatt STA100 Slave preset

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

The Hiwatt STA100 is a 100-watt slave power amplifier with no preamp or tone controls; it simply amplifies a line-level signal to speaker level. A level control feeds an ECC83 gain stage with feedback from the 16-ohm tap, then an ECC81 long-tailed-pair inverter drives four fixed-bias EL34s into a Partridge transformer, from a solid-state bridge supply with standby. It added power and cabinets to a rig driven by a head or preamp.

• Made in: UK
• Wattage: 100W
• Channels: 1
• Preamp tubes: 1× ECC83, 1× ECC81
• Power tubes: 4× EL34

Tags: british, vintage, power-amp, el34, 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.