Selmer Treble 'n' Bass 50 Mk II - Normal preset

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

The Treble ’n’ Bass 50 Mk II is a 50-watt British valve head from Selmer London. Bass and Normal channels each have two inputs, their own ECC83 with a treble/bass network and volume between its two stages, and are mixed into an ECC83 long-tail phase inverter. Two EL34s run fixed bias from a BY105 diode supply, with a GZ34 rectifier for the HT and 15 and 7.5 ohm outputs. It drops one ECC83 compared with the Mk I circuit.

• Made in: UK
• Wattage: 50W
• Channels: 2
• Preamp tubes: 3× ECC83
• Power tubes: 2× EL34

Tags: british, vintage, el34, 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.