[Amps] Old tubes

[on4kj]

We replaced those valves by the Philips QQE 02/5   QQE 03/12   QQE06/40  in
professional  and military gear in the sixties.
Late seventies they were replaced by transistors of the BLY serie.
Never had troubles with bad seals within the QQE serie, but after about two
years in CCS They lost more then 50% of power for other raisons . Thats
where the radio amateurs we were get them to play with, putting a 7V
fillament instead of the 6V3 they stayed in CCAS for an other couple of
months. Pumped cathode and fillament probably.
I guess that HF valves had, have, a longer life then the VHF ones.
Part of my professional history.......

Jos on4kj



----- Original Message -----
From: <peter.chadwick at Zarlink.Com>
To: <amps at contesting.com>
Sent: Wednesday, October 15, 2003 11:28 AM
Subject: [Amps] Old tubes


> I still see a fair number of older tubes of the 826,829, 832 variety being
> sold, as well as 5894s and so on. Previous experience with the 826, 829
832
> is that most of them are getting pretty old and have leaked quite badly.
> Has anyone else found this? 5894s and others of that ilk don't seem quite
> as bad - maybe the selas are better or it could be that they're not so
old.
> Of course, I realiee that a lot of the JAN 826 et al tubes were made in
WW2
> when getting quantities out was more important than a long life, and thus
> very good seals.
>
> 73
>
> Peter G3RZP
>
>
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