filter capacitor question

[mkruger]

when building a power supply... how far or close would you say a polypropylene capacitor when used for filtering an electrolytic needs to be to the electrolytic capacitor? will it be as effective if I locate the smoothing capacitor a few inches away via a wire? or does it need to be physically tied to the electrolytic capacitor leads?

more specifically I'm working with large electrolytics (450v 820uF) and .1uF 600v polypropylene for tube preamp projects on a 320vdc power supply.

-mike

 

[Guest]

[quote author="mkruger"] few inches away via a wire? or does it need to be physically tied to the electrolytic capacitor leads?
[/quote]
polypropylene is used to short rectifier hi-freq interfering noise.
place it close to rectifier. Sometimes it is at the some leads as diode,
paralel with each.
xvlk

 

[Ethan]

If using the polyprop to shunt, the closer to the lytic the better. From what I understand it is important to have low impedence to bleed off the DC leakage especially taking into consideration the load resistance the cap has to feed into.

 

[mcs]

When you use large electrolytics, why not just solder the PP cap on the electrolytic terminals?

Best regards,

Mikkel C. Simonsen