Silvertone 1421 (10XL) preset

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

The Silvertone 1421 '10XL' is a small single-ended combo. Two inputs feed a Volume control and a 12AX7A gain stage, then a Tone control and a second 12AX7A stage driving one cathode-biased 7189 (a heavy-duty EL84) into a single-ended output transformer, with no negative feedback. Tremolo comes from a 12AX7 phase-shift oscillator with Speed and Depth that modulates the second gain stage's cathode. A 6X4 valve rectifies.

• Wattage: 5W
• Channels: 1
• Preamp tubes: 2× 12AX7
• Power tubes: 1× 7189

Tags: el84, tremolo, class-a, low-wattage.

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.