Selmer Truvoice Universal 25U preset

Close · 77/100 confidence. Most values readable. Minor gaps filled by inference from similar circuits.

The Selmer Truvoice Universal 25U (drawing 1051) is an AC/DC tube public-address amplifier, not a guitar amp. Two identical transformer-coupled mic inputs and a gram input each feed a KTZ63 pentode, with their own volumes and a shared tone control. A DL63 triode drives an interstage phase-splitting transformer feeding four KT33C beam tetrodes in parallel push-pull. Three U31 half-wave rectifiers run off the mains, with a series heater string.

• Made in: UK
• Channels: 1
• Preamp tubes: 3× KTZ63, 1× DL63
• Power tubes: 4× KT33C

Tags: british, vintage, mid-wattage, 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.