Hello! One 3CX800 is inside the same as two 8875s. I have asked before the
following: why not replace the 8875s with triode connected 8072s (or 8122s
or that requires some mechanical changes and is maybe complicated? ). There
is also this 8121 that is cooled in the same way as the 8875 but quite hard
to find surplus. The 8072 is inside the same as the 8122 and the 8121. The
difference is in the way they are cooled: 8072/ conduction cooling (It is
easy to make a home made external cooler for transverse cooling just as in
the original 8875s ) -- 8122/axial-flow forced air using squirrel cage
fans-- 8121/ transverse cooler using muffin fans. They were made by RCA
before. Now by BURLE. EIMAC has made a rugged versions with the suffix W.
LA8AK reported years ago shorts problems with the 8122. Does anybody now
anything about this?
Is this not a cheaper solution? I found surplus 8072s cheap here in Sweden
as they were used in 400 MHz FM. They can take 100 mA maximum grid current
and could the max screen grid current even be higher. The old Signal One
used one also.
Hej daa de Hans SM5KI
----------
>Från: RichyRusso@aol.com
>Till: amps@contesting.com
>Ämne: [AMPS] MLA-2500 mods
>Datum: tis 9 nov 1999 01.27
>
>
>
>
>
> Hi Rich here,
>
> I am new to the group and I interested in converting a Dentron MLA-2500
>from 8875's to a pair of 3cx800a7's. Does anyone have the plans to make such
>a swap?
>I have some documentation to convert the amp to other tubes but I am
>interested in the above modification. If anyone has done this, I would
>appreciate some pointers,pics, pitfalls etc.... Tnx in advance!! Richy
>
>--
>FAQ on WWW: http://www.contesting.com/ampsfaq.html
>Submissions: amps@contesting.com
>Administrative requests: amps-REQUEST@contesting.com
>Problems: owner-amps@contesting.com
>Search: http://www.contesting.com/km9p/search.htm
>
>
--
FAQ on WWW: http://www.contesting.com/ampsfaq.html
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|