Overview
This listing is for one matched pair (2 valves) of genuine Philips ECC83 / 12AX7A new old stock (NOS) valves from the Philips Heerlen factory in the Netherlands.
Although branded "Electronics for Medicine" and carrying the medical Caduceus symbol, the valves have genuine Philips Heerlen acid-etched factory codes on the glass, confirming their origin. They date from approximately 1966–1967.
These are short-plate ECC83 valves, fully interchangeable with 12AX7 and 12AX7A types. The medical branding reflects their intended professional application rather than any electrical difference from standard Philips production.
Condition
These are genuine new old stock (NOS) valves that have never been used in service. They have been stored loose as part of a large quantity and therefore may show minor storage wear to the printed logos together with light oxidation on the pins. They are not supplied in original cartons.
The photographs are representative of the valves you will receive. Cosmetic printing may vary slightly between pairs, but all valves are the same Philips Heerlen construction and have been matched for electrical performance rather than appearance.
Testing & Matching
Every valve has been tested on an AVO Mk III Valve Tester, measuring both plate current and transconductance (mutual conductance).
Each pair has been:
- Matched between the two internal triodes within each valve.
- Matched as a pair for closely similar electrical performance.
- Confirmed to test comfortably above published data book specifications.
I have divided this large batch into several closely matched groups. If you purchase more than one pair from this listing, the additional pairs supplied will be of very similar electrical performance.
Applications & Suitability
The Philips Heerlen factory produced some of the finest ECC83 valves ever manufactured, and these are sought after by audiophiles, recording studios, guitar amplifier enthusiasts, hi-fi restorers and professional audio engineers. Their low-noise characteristics and excellent consistency also make them highly suitable for high-quality preamplifiers, microphone preamps, vintage test equipment and laboratory instrumentation.
The unusual "Electronics for Medicine" branding makes these particularly interesting to collectors while retaining all of the desirable electrical characteristics associated with Philips Heerlen ECC83 production.
Included
Your purchase is for two matched valves (one matched pair). Additional matched pairs are available while stocks last.