Thread: EF91 to EF80
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Old 4th Oct 2019, 7:49 am   #58
Radio Wrangler
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Location: Fife, Scotland, UK.
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Default Re: EF91 to EF80

Back in the sixties, I remember that the EF80 was looked upon as a 'telly valve' and if one turned up in any other application it was looked askance at and dismissed as a cheapening exercise or maybe just what the designer had in his junk box.

This was probably grossly unfair on the EF80.

At the time, I was making myself progressively better oscilloscopes, and I'd bought a tea-chest of surplus CV138 (EF91/Z77/6AM6....) from Jim Fish at his shop on Chapel Hill. So I guess I fell into the 'it's what he had in his junk box' camp. I also had plenty of EF80s in the junk box, but I'd never have thought of using them back then.

I guess the EF80 suffered typecasting and an image problem. The nasty staining seen inside old ones didn't give an aura of high quality.

The EF80 is also still so cheap that the audiophiles won't latch onto it. Zero, possibly negative, esotericity!

If I ever do a valve data book, I think I'll put a column in the tables labelled 'esotericity' maybe defined as a factor of today's market price divided by original price when new.

David
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