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Automatic Valve Tester
In designValvesTest gearPico
Last updated 29 September 2026
A modern valve tester in the AVO tradition. Instead of selector switches, relays connect each socket pin to the right electrode supply, set automatically from a database of valve types. It tests shorts and leakage, emission as a percentage, mutual conductance for matching, and gas.
Sockets cover B7G, B9A, International Octal, Loctal, Rimlock and the older B4, B5 and B7 bases, plus dedicated sockets for battery valves: several thousand valve types in all.
At a glance
| Tests | Shorts, emission %, gm, gas |
|---|---|
| HT | Up to 300 V |
| Heaters | 1.2 – 26 V, regulated DC |
| Controller | Raspberry Pi Pico 2, 3.5″ TFT |
Block diagram
Click a drawing to open it full size.
Documentation
The full design report, schematics and parts list will be published here once the project has been built, tested and filmed.