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In Reply to: An interesting discover on the k40 pio caps. posted by Michael Samra on April 30, 2007 at 00:10:48:
OK, but any stray capacitance between cap and case is now shunt capacitance in your circuit.
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Tre
so far the response sweep I did on the preamp and distortion check showed similar numbers both ways..I think the k40 is made so its doesnt have a lot of stray capacitance being used in sophisticated military applications but I could be wrong.I know the vitaman Q caps were made to ground the shields on many of the caps so I would think the k40s would be a similar circumstance.
That's true of the Russian Telfons. The capacitor inside is suspended from steel pins set in glass, separated from the external metal case by a few millimeters of air around the cylindrical face and double Teflon barriers on either end.
Thermionically addicted.
Do you have a capacitance meter? I have a Sencore "Z meter" that makes it easy.I was shocked to find a lot of stray capacitance between the cap and case on some vintage Aerovox caps that I'm using for coupling.
I just now tested a Sangamo 8uf 600WVDC cap. There is 370Pf between cap and case.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
yes I bought an LC75 before xmas and I have an old heath which I love for filter caps and then I have cheap POS tenma for mica caps and just value checks but the LC75 is an inductance meter also and your is to I imagine..I used to have an esr meter I used for service of SS gear and I cant find it anywhere..Its probably in my attic.
Yep, and it's non-trivial in some circumstances. Very worth measuring.
Thermionically addicted.
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