[NJARC] non-Polarized Capacitors

[NICHOLAS SENKER]

With a little practice I'll be able to spell your name correctly John.
For crossovers using back to back electrolytics, you don't need more than 50 volts or so and these are much less expensive.
Nick Senker

----- Original Message -----
From: John Ruccolo <jr6v6gt at yahoo.com>
To: NICHOLAS SENKER <ns539 at embarqmail.com>, Al Klase <al at ar88.net>
Cc: njarc at mailman.qth.net NJARC <njarc at mailman.qth.net>
Sent: Sun, 18 Oct 2009 21:25:56 -0400 (EDT)
Subject: Re: [NJARC] non-Polarized Capacitors

Hi Al/Folks,

I wonder -- does it matter if you connect the negative leads together or the positive leads, as long as they're "back to back?" (*not* in series, of course).

The larger mylar film caps are surprisingly expensive. I recently ordered some 1UF/630V for the club, and they were 2.26 apiece. I wonder what 4.7's or 10's or 22's cost from Mouser; they must be pretty pricey. I'll check the catalog or online.

Of course, if you're rebuilding a really good quality pair of speakers, then they're worth it.

Regards,

John R.

--- On Sun, 10/18/09, Al Klase <al at ar88.net> wrote:

> From: Al Klase <al at ar88.net>
> Subject: Re: [NJARC] non-Polarized Capacitors
> To: "NICHOLAS SENKER" <ns539 at embarqmail.com>
> Cc: "njarc at mailman.qth.net NJARC" <njarc at mailman.qth.net>
> Date: Sunday, October 18, 2009, 3:38 PM
> Just remember 
> Reply = Poster
> Reply All = Everyone
> 
> _________________________________________________________
> Nick's right.  The commercial non-polarized
> electrolytics amount to 
> being back to back polarized units, and that makes an
> acceptable 
> substitute.  However, in my limited experience
> rebuilding vintage 
> speakers, the years have not been kind to these
> things.  They change 
> value significantly with age, and in speakers, especially a
> stereo pair, 
> this has audible implications.
> 
> There are high value, 2.3, 4.7, 10, 22 uF, metalized
> polyester caps 
> floating around that can be series-paralleled to get you
> where you need 
> to be, and their values should remain constant for many
> decades.
> 
> Let me know what you need, and I'll rifle through the
> boxes.
> 
> Al
> 
> NICHOLAS SENKER wrote:
> > Just remember 
> > Reply = Poster
> > Reply All = Everyone
> >
> >
> _________________________________________________________
> > For John Rucollo and Steve Colandra; we were
> discussing non-polarized caps for speaker crossovers; these
> are available commercially and I think I have some; will
> bring them to the swapmeet.
> > According to my Popular Science 'How to build your own
> Radio and Hi-Fi' manual; you can make your own non-polarized
> caps by connecting two regular electolytics
> 'back-to-back'.  Connect the negative leads together
> and use the positive leads for speaker connections.
> > For a 2000 hz crossover at 8 ohms, you need a 10 mfd
> cap but if you put two caps in series as above you need
> twice the capacitance; in this case, 20 mfd each.
> > Nick Senker 
> >
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> 
> -- 
> Al Klase - N3FRQ
> Jersey City, NJ
> http://www.skywaves.ar88.net/
> 
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