What tubes does the Davoli UP4 EL504 Power Unit - Main use?

The Davoli UP4 EL504 Power Unit - Main uses 4× EL504 power tubes.

When was the Davoli UP4 EL504 Power Unit - Main produced?

The Davoli UP4 EL504 Power Unit - Main was produced 1966–1974.

Davoli UP4 EL504 Power Unit - Main preset

Verified · 81/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The Davoli UP4 EL504 Power Unit is a four-tube output stage using EL504 beam tetrodes, the Italian variant of the EL34 family. This modular power unit was designed to integrate with Davoli's preamplifier lineup, and its four-tube configuration suggests a substantial output rating in the 80–120 watt range.

Years produced: 1966–1974
Made in: Italy
Channels: 1
Power tubes: 4× EL504

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.