Sunn Sonic I-40 preset

verified · 92/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The Sunn Sonic I-40 (June 1967 schematic) is a single-channel valve head. Two inputs feed a 7025/12AX7 with a Bass Boost switch, a Volume, and passive Treble and Bass controls with a Hi Boost switch. A 7199 pentode-triode serves as gain stage and phase inverter, with feedback from the 16-ohm tap, driving two EL34s in adjustable fixed bias into a 3-40T output transformer. A GZ34 valve rectifier with choke and standby supplies about 445 V.

• Made in: USA
• Wattage: 40W
• Channels: 1
• Preamp tubes: 1× 12AX7, 1× 7199
• Power tubes: 2× EL34

Tags: american, vintage, el34, mid-wattage.

Schematic-derived preset files for the Neural DSP Quad Cortex and 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.