[Top] [All Lists]

[AMPS] Plate RFC choke design

To: <>
Subject: [AMPS] Plate RFC choke design
From: (km1h @
Date: Thu, 26 Mar 1998 22:51:16 EST
On Thu, 26 Mar 1998 18:10 -0700 (PDT) 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 
>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

You don't need to buy Internet access to use free Internet e-mail.
Get completely free e-mail from Juno at
Or call Juno at (800) 654-JUNO [654-5866]

FAQ on WWW:     
Administrative requests:

<Prev in Thread] Current Thread [Next in Thread>