Sunn Beta Lead - Channel B preset

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

The Beta Lead is the 100-watt (into 4 ohms) solid-state guitar head in Sunn's late-1970s Beta series. Channels A and B are identical, each with its own input and a Drive control working on an op-amp stage and a CMOS inverter stage chosen for its soft, tube-like limiting when overdriven, plus its own bass, mid and treble and reverb level. CMOS logic and FET switches select A, B or both from a passive footswitch or the jacks in use, ahead of a shared spring reverb, master, accessory loops and the Beta series power amp.

Known for: Buzz Osborne, Adam Jones, Kurt Cobain.

Heard on: Schism — Tool (2001).

Tags: american, vintage, solid-state, high-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.