Selmer Zodiac Twin 50 Mk II - Channel 2 preset

Verified · 88/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The Mk II Zodiac 50 is a two-channel valve amp from Selmer London. Channel 1 has an ECC83 input with treble, bass and volume; channel 2 has an ECC83 input into Selmer’s push-button tone selector with its own treble, bass and volume. A further ECC83 runs a light-dependent-resistor tremolo with depth and speed. An ECC83 long-tail inverter with presence drives two fixed-bias EL34s, with a GZ34 rectifier at about 455 V and a BY105 bias diode.

• Made in: UK
• Wattage: 50W
• Channels: 2
• Preamp tubes: 4× ECC83
• Power tubes: 2× EL34

Tags: british, vintage, el34, tremolo, mid-wattage, 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.