Capacitor Measurements

[AKprentice]

I came across this link by accident the other day:

http://members.aol.com/sbench102/caps.html

It is the first time I have seen measurements that show capacitor non-linearity. Tants look really bad & surprisingly (to me) paper in oil are best.

Andy

 

[zanash]

I alway say don't use tants for the signal path ......I've recently discovered PIO's for myself rather than just reading about them ....

for me they sound "right" where as a number of audio grade caps seem to emasculate the music signal in comparison.

 

[martin clark]

For coupling purposes those pics nicely confirm the importance of using substantial bias across tants - notice the improvement when the DC bias 1/2 rated voltage or more (70 -100vDC across a chain of 5 no. 35v-rated parts). Then the curve is about as flat as you like.*

Yes it's possible to better tants as coupling caps, but quite hard to do so in such a compact part at reasonable capacitance values - and cost!


*this will of course apply to their use as decoupling caps also - it *is* a signal path, says Mr. Kirchoff.

 

[martin clark]

I must add - if you want a reason for not using or specifying tantalum caps, I think the ethical concerns are much more compelling than the musical ones. Example 1, example 2.

 

[Basil]

A quote from http://sound.westhost.com

Tantalum: Very high capacitance per unit volume, but probably the most unreliable capacitor ever made. I do not recommend their use unless there is no alternative (this is rare).

 

[Paul R]

Also scroll down to section 5.8 here.

Paul

 

[teddy_pardo]

Coincidentally, just for fun, yesterday evening I started experimenting with home made PIO capacitors:

Two 5x25cm sheets of kitchen aluminium foil with two slightly larger peaces of paper dumped in oil (aluminium-paper-aluminium-paper). I rolled it like a cigarette and was surprised to measure about 10uF !!!

The whole thing can than be wrapped with blu-tac, epoxy, heat shrink, candle wax, acrylic, whatever... I'm curious to check how it sounds.

Next step would be to start experimenting with materials: copper foil, silver foil, different papers, different oils, a lot of fun...

Then, instead of rolling the foils, we can try using aluminium-paper-aluminium and fold them like a concertina. This will create the equivalent of a multi-layer with probably lower ESL... a whole new world of DIY.

 

[Basil]

Next step would be to start experimenting with materials: copper foil, silver foil, different papers, different oils, a lot of fun...

Could I suggest extra virgin olive oil, which ought to guarantee a pure sound!

As for paper how about Rizla extra large, for reggae!

 

[stevew_w]

Next step would be to start experimenting with materials: copper foil, silver foil, different papers, different oils, a lot of fun...

You should really get out more