It is very likely that the 1625 was war-time development to accommodate the 28 V
system voltage in larger aircraft. The 1625 is not listed in my RCA TT-3 from
1940,
so it must have been introduced later. A German tube history site
http://www.jogis-roehrenbude.de/EL34-Story/6L6-Story.htm lists the introduction
date as
September 1943, which seems somewhat late in the war.
It seems reasonable that the change to a 7-pin base was derived from
logistics reasons, so any mixing-up the 807 and 1625 should have been
impossible.
After the war the surplus 1625 was probably one of the cheapest RF power tubes
around.
Swedish surplus ads described the 1625 as "double filament voltage and half the
price" compared
to the 807.
The 1625 came to influence the power-tube markets long after after the war.
Philips made a special version of their 807 competitor, the PE 06/40, using the
same filament ratings and
base as the 1625. It was nomenclatured as PE 06/40 E, and was produced well
into the sixties.
73/
Karl-Arne
SM0AOM
----- Original Message -----
From: "Peter Chadwick" <g3rzp@g3rzp.wanadoo.co.uk>
To: <amps@contesting.com>
Sent: Thursday, July 26, 2007 4:22 PM
Subject: Re: [Amps] Gassy Tubes/Technology Museum looking for artifacts
> Does anyone know why the 1625 got a different base to the 807? I read
> somewhere it was developed for ARC for the Command transmitter, (just as the
> 12A6 was developed for the receiver) but there doesn't appear an inherent
> reason why the base was changed.
> 73
> Peter G3RZP
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> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>
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> 09:56
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