The 8873, 8874 and 8875 are all 3CX400 tubes. The 8873 is conduction
cooled and not made anymore, as I understand it. The 8874 is
an air cooled version, with airflow parallel to the axis of the
tube. These tubes run about $400 each, retail. The 8875 is
also air cooled, but with transverse airflow (perpendicular to
tube axis). Don't know if they are available anymore. All three,
of course, plug into the same socket. The 3CX400 is an excellent
tube - I used to get 625W output from one; it did this for many
years until I sold the PA (my eror - HI!). One merely has to
be sure one stays under 25mA grid current at all times, and the
tube works great and lasts long - HI!
Hope this helps!
Paul ND2X/5
>--- Original Message ---
>From: Chris Tran GM3WOJ <gm3woj@talk21.com>
>To: amps@contesting.com
To: <amps@contesting.com>
>Date: 6/19/01 1:03:46 AM
>
>
>Hello all
>
>My OT friend Tom GM2BMJ needs to replace
>the 8873 in his Heathkit amp. I told him that
>replacement tubes are difficult to find and
>expensive.
>
>Any suggestions about either a source of 8873
>tubes, or mods. to change it to a more easily
>available tube (e.g. 4CX800) ? (I'm guessing
>that modification would be too difficult an option,
>having to change the socket, fit a blower, etc.)
>
>Thanks - 73
>Chris GM3WOJ
>gm3woj@talk21.com
>
>
>
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>
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