[sdiy] Re: Kemet Multilayer (was Walt Jung and Richard Marsh'sCapacitors article)

[Magnus Danielson]

From: harry <harrybissell at prodigy.net>
Subject: Re: [sdiy] Re: Kemet Multilayer (was Walt Jung and Richard  Marsh'sCapacitors  article)
Date: Sat, 27 Jan 2001 18:55:12 -0500

> Hi Magnus (et al)

Hi Harry,

> <liberal snip>
> 
> Magnus Danielson wrote:
> 
> > > Are the Kemet a temperature stable variety ???  They ARE
> > > rugged.  We use them for decoupling... and even to simulate the
> > > gates of very large IGBTs... they are really tough and take a hell
> > > of a lot of AC dissipation.  But for audio I'm not sure.
> >
> > Oh dear... now we are there again....
> >
> 
> My point was not that ceramics usually suck for audio... just... how
> bad do they suck.  For interstage coupling of let's say... the noise
> source in Chris' MiniModular how would you HEAR if there was any
> distortion.  It might "color" the sound but you would probably not
> notice. Hence the ceramics "might" be ok. As I've said I don't use
> 'em for that.
> 
> For the caps in a VCF they are no damn good.  Ditto VCO.  But maybe in some
> envelope generator apps... like pulse forming, they are fine.

Agree. If you have *really* quick transititions, consider if the
parasitic inductance can be a killer, if so, ceramics just might be
the cure and not the killer. Most audio will best do without them
thought.

However, I think they can do a good job on the powersupply lines, but
most of the time people doesn't engineer PCB layout with low
inductance paths to decouple-caps in mind. No wounder things
cross-couple like hell for some.

> The trick is to use the correct part and learn why you are using that part.

Right.

> PS.  Hey Magnus, if you use much Teflon you got more money than me !!!

Maybe I do, maybe I do... but:
Sorry Harry, call of the hunt, my default is Polypropylene ;)
They are *way* much easier to find.

Cheers,
Magnus