Use X-class dielectric capacitors with a working voltage much higher than
the maximum voltage they are going to be subjected, that will reduce the
voltage dependence of capacitance.

Never use Y-class dielectric capacitors with audio, the dielectric is
piezoelectric and they may act as microphones, picking vibration from the
board.

Cheers,
Isaac

Em seg, 22 de abr de 2019 13:39, Bob Blick <bobblick@outlook.com> escreveu:

> Hi Justin,
> Generally a bad idea to use ceramic caps for audio filters unless they ar=
e
> NPO. The capacitance of large value ceramics decreases with increasing
> voltage. Everything looks great with a single sine wave, but you get
> intermodulation distortion with actual audio going through it.
>
> For best performance, use any type of film capacitor, such as mylar.
>
> Bipolar electrolytics are OK, but the tolerance is usually poor and they
> also age really quickly.
>
> Friendly regards, Bob
>
> ________________________________________
> From: piclist-bounces@mit.edu <piclist-bounces@mit.edu> on behalf of
> Justin Richards
> Sent: Monday, April 22, 2019 5:16 AM
> To: Microcontroller discussion list - Public.
> Subject: [EE] Typical ESR for 1uF non-polarised cap
>
> Can I use a ceramic 1uF cap to replace a 1uF non-polarised electrolytic i=
n
> the final stage of a woofer driver?
>
> What should a typical ESR range be for a 1uF non-polarised electrolytic?
>
> Details:-
> A Behringer B115W requires replacement 1uF non-polarised caps.
>
> The original electrolytics measured approx 50ohms ESR.  I haven't been ab=
le
> to find anything definitive regarding ESR values for non-polarised
> electrolytic except to find a reference to them having generally higher E=
SR
> than their polarised counter parts.  However, I have to assume 50ohms ESR
> is really bad.
>
> Trawling the archives I found this from Olin "...There is really no place
> left today for a 1uF electrolytic capacitor..."
>
> In the B115W these caps (c33 and c34 if the attachment made it) are used =
to
> connect the two woofer drive traces to ground.  They appear just before t=
he
> final inductor/transformer.
>
> [image: image.png]
>
> What say ye.
>
> Justin
>
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