On Thu, 26 Mar 1998 18:10 -0700 (PDT) kdbalmforth@mail.hac.com writes:
>Does anybody have a proven design for a plate choke?
>
>I'm building a 160-10 (no WARC) amp using a pair of 3CX800A7 tubes,
>(1.5A max
>Ip). I've seen lots of plate RFC designs that use anywhere from 80 uH
>(Ten Tec
>Titan), and on up.
>
>All the homebrew designers treat winding a choke as a black art. I've
>got
>various lengths of 1" and 1.25" Delrin rod to work with, and would
>like to use
>#20 wire. It can't be that hard, can it?
>
>73 - Kevin N6ER
Its moderately easy if you own a GDO Kevin. If not it may be easier just
to buy one...the big Ameritron is good and also reasonable.
I would not use Delrin. Stick to ceramic or hard Teflon.
#20 wire is serious overkill and just complicates the design.
One design I have used in numerous amps including 2 and 3 hole 3CX800's
and 3-500Z's is :
3 5/8" of #28 Soldereze closewound on a 3/4" diameter ceramic form. It
measures 188uh. I hold the cold end in place with Scotch #27 HV
fiberglass tape.
Different wire size and even insulation can alter resonances a lot.
The only true test is in the amp. The GDO gets you close but every layout
has its own pecularities, coupling, etc.
GL Carl KM1H
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