[Amps] (Perhaps) A plate choke too far ...

[James Colville]

What about this theory? See the lower part of the page.

http://www.kk5dr.com/chokes.htm


73
Jim W7RY



On Thu, Jan 14, 2010 at 8:32 AM, Radio WC6W <wc6w_amps at yahoo.com> wrote:

> Hi Hardy,
>  True... but, the DC will "kill" the core at HF.
>
>  Look at the bottom of page 129 on this link
>
> http://fair-rite.com/newfair/pdf/CUP%20Paper.pdf
>
>  to see the ... damage.
>
>  And operating on the curve would also likely introduce some distortion.
>
> 73 & Good morning,
>  Marv WC6W
>
> http://wc6w.50webs.com/
>
> --- On Wed, 1/13/10, Hardy Landskov <n7rt at cox.net> wrote:
>
> > From: Hardy Landskov <n7rt at cox.net>
> > Subject: Re: [Amps] (Perhaps) A plate choke too far ...
> > To: "Radio WC6W" <wc6w_amps at yahoo.com>
> > Date: Wednesday, January 13, 2010, 7:36 PM
> > The whole object of an RF Choke is to
> > kill the gain of the tube at low frequencies and DC while
> > looking transparent at 1.8 through 30 MHz right? Mu has no
> > meaning a DC, neither does XL.
> > I guess I am not understanding this thread.
> > Hardy N7RT
> >
> >
> > ----- Original Message ----- From: "Radio WC6W" <wc6w_amps at yahoo.com>
> > To: <amps at contesting.com>
> > Sent: Wednesday, January 13, 2010 8:06 PM
> > Subject: [Amps] (Perhaps) A plate choke too far ...
> >
> >
> > >   The other day, just for fun, I swept
> > a bunch of ol' RF chokes --  solenoid wound, pie wound,
> > etc.  All of them exhibited nasty resonances somewhere
> > within the HF spectrum.
> > >
> > >   I then wound a few experimental coils
> > on some toroids and one on a type 43 core worked
> > exceptionally well -- very flat response with no resonances
> > anywhere below 50 Mhz.
> > >
> > >   The only gotcha with this part is
> > that in a real world application the DC plate current would
> > saturate the toroid, killing the mu & the uH's.
> > >
> > >   Now here's where this concept crosses
> > over in the silly side...
> > >
> > >   The saturation problem could be
> > overcome by running an out of phase DC current, servoed by
> > the plate I, through a 2nd winding on the core.  This
> > second winding would need to be RF isolated with a choke of
> > its own but, for a single turn winding a 10uH (air core)
> > choke would be sufficient. The required single turn current
> > would be on the order of 10-15 amps. Sounds bad but, no real
> > voltage is required -- 10 Amps at .1 volt is only a
> > watt.  In a fortunate circumstance, this current might
> > be obtained "free" in series from a DC heater supply.
> > >
> > >   Searchin' around the all knowing
> > internet only uncovered a similar scheme to cancel the plate
> > DC in an "audiophile" single ended output transformer.
> > >
> > >   Has anyone ever see this done?
> > >
> > > 73 & Good evening,
> > >   Marv WC6W
> > >
> > > http://wc6w.50webs.com/
> > >
> > >
> > >
> > >
> > > *
> > >
> > >
> > >
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> >
> >
>
>
>
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