[sdiy] electrolytic coupling capacitors

[Theo]

Considering your schematic the Mylar caps might be overkill.
And that might be a under statement. ;-)
If you feel you need the input caps you may use bipolar elcos or 2 normal
elcos of double the value mounted "face to face"

Also you are shorting the input if a channel is set to 0.
You may consider taking the signal from the whiper of the pots.
47k pots would give you "standard" line input impedance.

HTH
Theo


----- Original Message -----
From: blitz <blitz at nmt.edu>
To: Glen <mclilith at charter.net>; <synth-diy at dropmix.xs4all.nl>
Sent: Monday, November 01, 2004 9:20 AM
Subject: Re: [sdiy] electrolytic coupling capacitors


> jeez, $4 each, I'd say that's a little pricey for this project.  I
> will stick with the electrolytics I have, still a bit unsure on the
> polarity though.  I just read something that stated you want the
> greatest impedance to be on the foil side (negative?), is this right?
>
> -Joe
>
> At 1:11 AM -0500 11/1/04, Glen wrote:
> >Content-Type: text/plain; x-avg-checked=avg-ok-16417605; charset=us-ascii
> >Content-Transfer-Encoding: 8bit
> >
> >At 04:12 PM 10/31/04 , blitz wrote:
> >
> >>I'm building a small mixer with gain and need to couple the the
> >>output to remove DC.  From circuit analysis I need a 10uF cap in
> >>series on the inputs and output to remove the DC offset.  10uF is
> >>pretty large, so the only available caps I have are electrolytic with
> >>polarity.  Can I use an electrolyitic in place of a non-polarity
> >>coupling capacitor?  How do I know which end the +/- should be
> >>connected to?
> >
> >Just in case you didn't know, you can actually purchase mylar caps in the
> >10uF range. They're much larger physically, and they cost more than an
> >electrolytic, but you don't have to worry about polarity. Some people
also
> >say that they sound better. There are supposed to be some quirky
nonlinear
> >properties involved with electrolytics.
> >
> >Here's a link for a 10uF Mylar cap, in case you want to pursue that
route:
> >
>
>http://mcm.newark.com/NewarkWebCommerce/mcm/en_US/endecaSearch/partDetail.j
s
> >p?SKU=31-0330&N=4
> >
> >I'm sure you can also find these through other vendors. This is just the
> >first reference I found.
> >
> >You can also get non-polarized electrolytics, but these are really two
> >polarized electrolytics wired in series, one "turned around backwards"
> >compared to the other one. Since your signal is then going through two
> >electrolytics, I would expect possibly more signal corruption than with
the
> >polarized variety.
> >
> >Personally, for a "basic" mixer, I would probably go with electrolytics.
If
> >I wanted to build some really nice preamp, I might experiment with the
> >large valued mylar caps.
> >
> >
> >later,
> >Glen
>