Acutally, the delailed specs state that they can be used up to 300W plate
dissipation if sufficient conduction cooling is provided.
They are identical to the 8122. Even the characteristic curves. Sometimes they
were run at higher power with clamp
on heat sinks with the amplifier in a bath of oil for specialized applications.
I had some 4CN15A tube that we in an oil
bath and they even had wires directly soldered to them rather than a socket.
73
Bill wa4lav
________________________________________
From: Michael Clarson [wv2zow@gmail.com]
Sent: Friday, May 09, 2014 3:46 PM
To: Fuqua, Bill L
Cc: amps@contesting.com
Subject: Re: [Amps] Using computer CPU coolers on GI46b triode ?
Bill: Yes -- Familar with the 8072. It was used in a lot of land mobile radios,
conduction cooled. They would run at 100 Watts out. Plate dissipation was only
100 Watts in the conduction cooled mode. To contrast conduction vs forced air,
the 8122, same tube with forced air heat sink had a 400 Watt dissipation. The
8072 was a deal in the late 1970s. One could buy them new via conventional
channels for $20. --Mike, WV2ZOW
On Fri, May 9, 2014 at 2:55 PM, Fuqua, Bill L
<wlfuqu00@uky.edu<mailto:wlfuqu00@uky.edu>> wrote:
I once made a heat sink for 4 6AG7 tubes by drilling out a large block of
aluminum boring
holes in it aprox. 1 in dia and using a tungsten tipped saw blade cut slots for
fins. Worked
well. Somewhere I have some heat sinks for some 8072's ( 8122 without fins)
used in
a 500 watt plasma generators. Some were made of sheet metal, and others were
machined
blocks, both were forced air cooled, neither worked very well. The manufacturer
had to
can the product. They were not reliable. At that time 8072's were much cheaper
than 8122s.
I would not recommend use of heat pipes like those used in many computers. A
computer has
to dissipate much less heat than a power tube.
73
Bill wa4lav
_______________________________________
From: Amps [amps-bounces@contesting.com<mailto:amps-bounces@contesting.com>] on
behalf of Joe Subich, W4TV [lists@subich.com<mailto:lists@subich.com>]
Sent: Friday, May 09, 2014 2:17 PM
To: amps@contesting.com<mailto:amps@contesting.com>
Subject: Re: [Amps] Using computer CPU coolers on GI46b triode ?
On 5/9/2014 11:12 AM, Carl wrote:
> Subject: Re: [Amps] Using computer CPU coolers on GI46b triode ?
>
> I can easily see boring a CPU sink as a simpler alternative as long as a
> round silicone rubber chimney isnt required.
That may be possible with an old "block with fins" type heat sink but
many of the newer ones use a relatively thin plate/heat spreader and
tubes filled with a heat transfer fluid. The tubes bend upward to a
radiator in the normal air flow or with or have a fan mounted to the
radiator. Drilling/boring one of those would damage the heat tubes
and render it useless.
73,
... Joe, W4TV
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