Bogen J-330 preset

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

The Bogen J-330 is a 30-watt tube public-address amplifier from the mid-1950s. Three microphone inputs each have a 6SF5 preamp and their own volume, and a phono input has its own volume; all mix into a fourth 6SF5 stage with bass and treble controls. A 6SL7GT amplifies and acts as paraphase inverter for a cathode-biased push-pull pair of 6L6Gs with negative feedback, on a 5U4G rectifier, with 70 V line and speaker taps.

• Made in: USA
• Wattage: 30W
• Channels: 1
• Preamp tubes: 4× 6SF5, 1× 6SL7GT
• Power tubes: 2× 6L6G

Tags: american, vintage, 6l6, clean.

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.