The original PL-172 with glass seals is NOTORIOUS for air leakage and not
outgassing from the anode.....big difference.
Carl
----- Original Message -----
From: "RAY FRIESS" <rayfrijr@msn.com>
To: <Amps@contesting.com>; <chris@g3vbl.co.uk>
Sent: Saturday, May 06, 2017 11:32 AM
Subject: Re: [Amps] PL172 (8295)
I would not be too concerned about leakage. It happens, but very very
seldom. I have tubes that are still new in box from way back in WW2 that I
have used and none have ever shown air leakage. Easiest way to determine
if they are still good is to plug them in and fire up the rig.
Ray wa7itz
________________________________
From: Amps <amps-bounces@contesting.com> on behalf of Chris Pedder
<chris.g3vbl@gmail.com>
Sent: Saturday, May 6, 2017 8:11 AM
To: Amps@contesting.com
Subject: [Amps] PL172 (8295)
For the last 37 years my Hallicrafter HT33A has been sitting on the floor
in the garage with an 8295A (Ceramic) fitted. I have a pair of 'new in the
box' PL172s one of whose boxes is still sealed. Packing date was 6/67 so
that's almost 50 years.
I suspect that the glass seals will have leaked but is there anyone with
experience of these tubes after such a long period of time. If I were to
construct a hi-pot device, what sort of values should I expect from a
'good' tube? Thanks.
Chris G3VBL
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