Univox Stage 750B preset

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

The Stage 750B is a solid-state Univox bass amp from the late 1970s. Two inputs feed a discrete transistor stage, a volume control with a high-boost switch and a second gain stage, then treble, middle and bass controls. A Contour control built around a 550 mH inductor shapes the midrange ahead of the master volume and line out. A quasi-complementary transistor power amp drives a 4-ohm output and an 8-ohm extension-speaker jack.

• Channels: 1

Tags: solid-state, bass, vintage.

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.