Jeff,
David has collected lots of valve data, available at: http://www.g8wrb.org/
Regards.
Mark.
-----------------------------------------------------
At 23:26 26/01/2006, Will Matney wrote:
>Jeff,
>
>You may have to find some older tube books on ebay or one of the
>online book sellers from the 40's and 50's. You may also want to
>give Eimac, or maybe MPD (GE) a call and see if they have any other
>sheets available with different voltages. Just tell an engineer what
>you need and they may help. Another place to look is an older amp
>manufacturer who used the tube with the voltages your looking at.
>Sometimes they can have old test data sheets from jobs of the past.
>
>Best,
>
>Will
>
>*********** REPLY SEPARATOR ***********
>
>On 1/26/06 at 11:28 AM Xmitters@aol.com wrote:
>
> >In a message dated 1/26/06 10:13:31 AM Central Standard Time, r@somis.org
> >writes:
> >
> ><< The curves for 500v may be converted to other voltages by applying the
> > 3/2 power law.
> > >>
> >The 3/2 power law is only applicable over a fairly narrow range. This
> >approach is especially problematic when the control grid voltage is
> >positive at the
> >published screen voltage and it goes negative at the desired screen
> >voltage.
> >You also run into problems when calculating where the zero plate current
> >line is
> >going to be with the desired screen voltage compared to the published
> >screen
> >voltage. This comes about when you ratio out the desired versus published
> >screen voltage. To scale the grid voltage axis, you then multiply the
> >published
> >control grid voltages by this scale factor. Well, this approach does not
> >work
> >when you have to relocate the zero control grid voltage point at the new
> >screen
> >voltage. Zero times anything is zero.
> >
> >I verified this by examining several tubes that have curves for more than
> >one
> >screen voltage. I chose an observation point (plate voltage and plate
> >current) on one curve, then noted the grid voltage for that point. I found
> >the same
> >observation point on the other set of curves. I then applied the 3/2 power
> >law.
> >In some cases it was close, in other cases it was off by a mile.
> >Especially
> >in the case where the grid voltage for that observation point stats out
> >mapped
> >with a positive grid voltage, and then goes negative at the higher screen
> >voltage.
> >
> >For relatively small deviations in screen voltage from published to
> >desired,
> >the 3/2 law works quite well.
> >
> >
> >Jeff Glass, BSEE CSRE
> >Northern Illinois University
> >WB9ETG Since 1970
> >_______________________________________________
> >Amps mailing list
> >Amps@contesting.com
> >http://lists.contesting.com/mailman/listinfo/amps
>
>
>
>_______________________________________________
>Amps mailing list
>Amps@contesting.com
>http://lists.contesting.com/mailman/listinfo/amps
*******************************************
Mark Hill - G4FPH
E-mail: g4fph@mjha.co.uk
Current web pages at: www.g4fph.net
Old web pages at: www.qsl.net/g4fph
----------------------------------------------------------------------
Dipoles resonant on 1942 / 3720 / 7085 kHz
Three element wire beam coming soon on 14180 kHz!
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S witch off
I solate
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