What tubes does the Radford Ma Sta25 use?

The Radford Ma Sta25 uses 2× ECC83 preamp tubes and 2× EL34 power tubes.

When was the Radford Ma Sta25 produced?

The Radford Ma Sta25 was produced 1960–1975.

Radford Ma Sta25 preset

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

The Radford STA25 is a 25-watt British tube amplifier from Arthur Radford of Bristol, celebrated for its exceptional output transformers and precise circuit design. Originally intended for hi-fi stereo use, the STA25 found its way into guitar rigs for its clean, detailed, and dynamic response. It is one of the most respected British tube amplifiers of its era among audiophiles and collectors.

Years produced: 1960–1975
Made in: UK
Wattage: 25W
Channels: 1
Preamp tubes: 2× ECC83
Power tubes: 2× EL34

Tags: british, vintage, 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.