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MlinarS 30th March 2005 04:44 AM

Asc Oil Capacitors
 
Hello,
As stated on the ASC site polypropylene in oil capacitors model X386S-20-10-440 and X386S-50-10-440 are rated 440 VAC. My question is, can they be safely used in PSU at 550 VDC. Does any of you have experiance with this capacitors in this situation? TIA for the input.

Sherman 30th March 2005 12:37 PM

Re: Asc Oil Capacitors
 
Quote:

Originally posted by MlinarS
... polypropylene in oil capacitors model X386S-20-10-440 and X386S-50-10-440 are rated 440 VAC..., can they be safely used in PSU at 550 VDC....

Hi,
I just built a PS with a B+ of 425VDC using ASC caps rated at 370VAC. Peak voltage before everything stabilizes hits about 510VDC. I'm using valve rectification and voltage goes slowly from 0 to 510-520VDC then drops pretty quickly back to 425.

The supplier I purchased the caps from indicated an ASC cap rated at 370VAC could be used in DC circuits up to about 600VDC. I don't think that 550VDC would stress a 440VAC cap.

MlinarS 30th March 2005 03:58 PM

Thank you Sherman,
I tought that to. I read somwhere that VDC=VAC x 1.41, but I wasn't realy sure.
Some people say that this capacitors don't sound so good at first but they improve over time. What is your experiance in that regard? Thanks.

Sherman 31st March 2005 02:32 AM

Quote:

Originally posted by MlinarS
...I read somwhere that VDC=VAC x 1.41, but I wasn't realy sure.
Some people say that this capacitors don't sound so good at first but they improve over time...

Since rectifying AC (using SS rectifiers) generally results in DC voltage of about 1.41 x the AC voltage that is probably a good rule of thumb for using with the caps.

Maybe I wasn't listening closely enough at the beginning but I thought the amps sounded just fine with them from the start. I only have about 70 or 80 hours on them now so they are still pretty new. I would think that with new tubes, new trafos etc. it might be hard to pick out the effects of the caps.

MlinarS 31st March 2005 02:55 AM

Thanks Sherman

Sherman 31st March 2005 01:41 PM

Quote:

Originally posted by MlinarS
Thanks Sherman
No problem. Sorry I couldn't confirm/deny the effect on sound. Unlike many here I apparently have "iron ears" rather than golden ears. Still I like to listen to music and am enjoying my amps.


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