Tech Square

Posted by cheap-Jack (A) on March 17, 2008 at 11:58:48

In Reply to: RE: Polypropylene or polyester posted by ned664 on March 10, 2008 at 14:23:35

Hi.

Technically, the E/H hysteresis curve of PET (polyester, or polyethylene
terephthalate) is very slightly less linear than PP, but is already much better than mica, & low voltage ceramic.

I've used PP in hi-pass filters in loudspeaker X-over networks & signal paths where space is available. But for large cap values up to 10uF & low DC voltages, & space is not available, I've used PET (aka Mylar) as coupling caps in my tube & SS amps, even for the crucial phonostage I/P & O/P coupling.

Sound pretty OK & PET is much cheaper than PP of the same large capacitance.

c-J

PS: FYI, paper in oil caps is most linear but really good ones cost a fortune.