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Re: [Amps] PL172 (8295)

To: amps@contesting.com
Subject: Re: [Amps] PL172 (8295)
From: "Roger (K8RI)" <k8ri@rogerhalstead.com>
Date: Sun, 7 May 2017 22:22:24 -0400
List-post: <amps@contesting.com">mailto:amps@contesting.com>
I agree with Carl, I haven't seen a good PL172 (glass seal) in ages. The ceramic versions seem to hold up well.
I have an HT32B

73, Roger (K8RI)


On 5/6/2017 Saturday 11:46 AM, Carl wrote:
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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