Univox U-1050B - Channel 2 preset

Verified · 91/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The U-1050B is a Univox valve guitar head from the early 1970s. Two channels, each with Bright and Normal inputs, a 12AX7 triode stage and its own volume, mix into a second 12AX7 and shared treble, middle and bass controls. A 12AX7 long-tail inverter with a presence control and negative feedback drives four fixed-bias 6L6GCs from a silicon supply at about 475 V, with a choke, standby switch and an impedance selector for the speaker and extension jacks.

• Wattage: 100W
• Channels: 2
• Preamp tubes: 3× 12AX7
• Power tubes: 4× 6L6GC

Tags: vintage, 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.