Univox U-1246 - Channel 1 preset

Verified · 93/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The U-1246 is a two-channel Univox valve bass head of 1971, built by Unicord, not a solid-state amp. Each channel has Bright and Normal inputs, a 12AX7 triode stage and its own volume, mixing into a 12AX7 stage and shared treble, bass and middle controls plus presence. A 12AU7 phase inverter with negative feedback drives two fixed-bias 6L6GCs at about 670 V from a silicon voltage-doubler supply with standby, into 8- or 16-ohm speaker jacks.

• Made in: Japan
• Wattage: 60W
• Channels: 2
• Preamp tubes: 2× 12AX7, 1× 12AU7
• Power tubes: 2× 6L6GC

Tags: japanese, vintage, 6l6, bass, two-channel.

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.