[R-390] Source for axial caps

Tue Jul 27 13:08:08 EDT 2004

Hi Jordan and gang,

I like the 630V metallized polypropylene films made by Illinois
Capacitor (IC), available through AES (www.tubesandmore.com).  Pretty
cheap, under a buck for 0.1uF/630V.

You can get to their performance specs at this link (select the "MPW"
line):

http://www.illcap.com/Film.asp

Pretty low dissipation factor, rated to 105 deg C, and relatively small
in size compared to SBE 715P ("orange drops") (but still an *axial* that
fits all BA applications I've tried).  If you use 630V rated ones, you
may get a longer life in BA rx duty (200-350V typically), as capacitor
lifetimes increase as you "de-rate" temperature and applied voltage.
Good for bypass and coupling.

In fact, 400V polyester units should be plenty of capacitor for bypass
applications...and polyesters are rated to 125 deg F.  They have a
higher (worse) dissipation factor (i.e. lower Q/higher E.S.R.), but I'm
not certain that would matter much.  But, for not much more money
(cents), I just buy the 630V MPWs for everything and simplify my life a
little bit.

As an aside, I'm curious why "orange drops" are so popular in BA
restorations.  They look like they're better suited (and are
recommended) for audio coupling or high current/pulse bypass or
filtering.  I recall looking at their impedance vs. frequency once and
noting that 0.1uF units were getting rather close to their
self-resonance for 455 kHz applications.

My thinking is that I'd like to replace these capacitors once, at least
in my lifetime.  We're lucky to have such nice materials and
manufacturing these days.

73, Chris KA8WFC

-----Original Message-----
From: r-390-bounces at mailman.qth.net
[mailto:r-390-bounces at mailman.qth.net] On Behalf Of Jordan Arndt
Sent: Monday, July 26, 2004 7:07 PM
Cc: boatanchors; RACAL; Collins Reflector; R-390 Group
Subject: [R-390] Source for axial caps

Does anyone know a good source for axial caps ie .0047, .047 ,.022
etc.... @ 250-400V..? Preferably film type caps.. Poly tubulars etc...

73 de Jordan...

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