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@cox.net> wrote:
> From: Hardy Landskov <n7rt@cox.net>
> Subject: Re: [Amps] (Perhaps) A plate choke too far ...
> To: "Radio WC6W" <wc6w_amps@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@yahoo.com>
> To: <amps@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/
> >
> >
> >
> >
> > *
> >
> >
> >
> > _______________________________________________
> > Amps mailing list
> > Amps@contesting.com
> > http://lists.contesting.com/mailman/listinfo/amps
>
>
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