Today I received a delivery of a box of vacuum tubes, all primarily TV valves from the 1960s & 1970s. Was hoping for some radio valves, but no joy. At least I have these for future projects or I will sell them on eBay over the coming months; or maybe I’ll use a few of these in a couple of experiments. What to you think, anyone got some ideas?

Mullard

• EF9 – RF Pentode
• EL36 – Pentode Power Output
• UCH21 x 2 – Triode Heptode
• N308 – ??
• PL500 – TV Pentode Line Output
• PL36 – TV Output Pentode
• EV87 – ??
• ELB21 – ??

Radio Haltron

• U25 – ??
• X78 – ??

Mazda

• U191 x 3 TV Efficiency Line Diode

Tungsram

• 6SA7GT – Pentode Power Output

RCA

• 35Z5GT – Half-Wave Rectifier

KT (Electron)

• KY4 – ??

KR Tubes

• ISSK7 – ??

I suppose the first step is to try to find out something about the ones indicated with “??”. Some of these are models that I haven’t heard of before, so there is a little bit of homework to do over the next week or so.