Unknown Misc 2Xel503 Amp preset

Verified · 80/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

This miscellaneous amplifier schematic documents a design built around two EL503 output tubes, a less common tube type that was used in some European amplifiers of the 1960s and 1970s. The EL503 is closely related to the EL34 family but was produced by fewer manufacturers, making amps built around it relatively unusual. Without confirmed manufacturer attribution, this entry serves primarily as a circuit reference.

• Power tubes: 2× EL503

Tags: vintage.

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.