Found a pack of unused tube bases which I don't recognize. They're about the size of american octal, but with 9 pins spaced 36 degrees and no spigot slot. There's no base of that type on my Avo Valve Characteristic Meter Anyone know what they might be ? CRT bases of some sort ?
Jim Hawkins
9 pins wouldn't be enough for a Nixie, or a Decatron tube, but there are a lot of other such stuff around. I'll check the old Mullard and RCA books and see if anything comes close. we're off to Scotland on a commissioning trip this morning, back tomorrow so will look on the weekend.
Peter
-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk
It's MAGNOVAL Used in Europe mainly for Television Line-driver tubes. Like a large noval.
Robert
Picture here:
It does look like an octal socket with a ninth pin and no index slot on the central hole. I presume the central hole is for a glass protrusion from the tube envelope rather than from an actual plastic prong like on an octal tube.
Yes, some of the magnoval tubes had the evacuation stem at the base of the tube.
That's the one! I see it's the base for the EL509 (original version, not the re-engineered one, which is on a standard US octal) Thanks very much for the reference.
Jim Hawkins
These were mostly used for the PL509 and PL519 in horizontal flyback stages of European color TV sets. 300mA filament current. The usual bakelite bases would become charcoal over time because these tubes dissipated around 30 watts, and they needed all the air flow they could get.
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