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Old 16th Mar 2017, 6:17 pm   #17
DangerMan
Heptode
 
Join Date: Jul 2009
Location: Stoke-on-Trent, Staffordshire, UK.
Posts: 719
Default Re: The Mullard EL42

What are people's experiences of EL42 reliability?

I ask because every time I've encountered them in TV sets I've had problems.
Either they have been downright low emission, or show symptoms of being slightly gassy and becoming unusable when hot.
This has been most evident when used as frame output valves in sets where all the usual causes have already been eliminated, leading to much gnashing of teeth and pulling out of hair.

It has been compounded with NOS Mullard replacements showing the exact same symptoms, and only careful selection of old stock items... even such as those removed from car radios over 45 years ago... has saved the day and got the sets going and drift-free.

Perhaps it's a side effect of the rigid pins and button base which has permitted a few molecules of air to get in (?) but if so, no amount of running has ever got the getters to soak up this gas.

Or have I just been unlucky?

Pete
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