Jackson-Guldan 290 preset

Verified · 90/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The Jackson-Guldan 290 is a small circa-1950 amp with a metal chassis in a wooden cabinet, probably sold with a lap-steel outfit. Two instrument inputs mix into a single 6SJ7 pentode preamp, followed by one volume control (with the power switch on the pot) and no tone control. A cathode-biased, single-ended 6V6GT drives the speaker through a small output transformer, with a 5Y3GT rectifier. Simple, low-powered and quick to break up.

Tags: american, vintage, 6v6, class-a, 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.