Capacitor types - experts please help rank

[Bill Fitzpatrick]

I am interested in your ranking of film capacitor types.

Film and foil, metalized film, dielectric type (mylar, polyester, etc.) Best to worst.

You know the drill. This will be valuable info. for all.

 

[sreten]

do a search, already covered in some detail, sreten.

 

[claudio]

I suggest: http://www.capacitors.com/picking_capacitors/pickcap.htm

Claudio

 

[serengetiplains]

In my experience, and all other things being equal, capacitor ranking generally follows the dielectric constant of the dielectric: the lower the DC, the better the cap. With a lower dielectric constant comes lower dielectric absorption and related losses. Teflon and certain types of oil, wax and paper (DC ~ 2) are head-runners, therefore, as capacitor dielectrics, followed by polystyrene (2.2) and polypropylene (2.3), mylar (3.1) being somewhat further down the list. Air, of course, is the best dielectric (1.0). The better Nordost cables sound so good because they achieve a very low dielectric constant in their insulating material (1.3), combining teflon and air in a manner allowing very little contact between cable and teflon, rendering a mostly air dielectric. Polyethylene (2.25) is also quite good (Jena cables, I believe, are insulated with this substance).

The problem with low dielectric constant is a larger capacitor is required for a given capacitance. Manufacturers therefore may prefer a mylar capacitor over an electrically better performing cap simply due to size and $$ considerations.

 

[Yank]

Capacitors..

It all depends on what you want to accomplish.

Bob Carver explains how he uses capacitors on his website. No one person out there knows more than he.

www.sunfire.com

 

[jwb]

What's the application? In cetain applications Teflon film caps are unbeatable. But they don't make very good power supply filters.

If you are talking about dc-blocking caps in a signal path, I guess I'd say Teflon (but can't get large ones), Polypropylene film, Metallized polypropylene, Polyester, then the rest. Polypropylene film are staggeringly popular coupling caps in diy audiophile gear.

 

[sam9]

"Bob Carver explains how he uses capacitors on his website. No one person out there knows more than he."

I looked in the white papers and didn't see anything on the topic. Where should I be looking?

 

[analog_sa]

looked in the white papers and didn't see anything on the topic. Where should I be looking?

There is a short paragraph about caps in his amp essays. You are, however, excused for missing it as the essay makes such a hilarious reading that one can be easily distracted. It's even funnier if you've ever listened to a Carver amp.

 

[serengetiplains]

In my experience, teflon caps make fantastic power supply bypass caps. Their effect on distortion is measurable.

 

[tom1356]

Re: Capacitors..

It all depends on what you want to accomplish.

Bob Carver explains how he uses capacitors on his website. No one person out there knows more than he.

www.sunfire.com

He should start putting some of that knowledge to use in amp designs.. I wonder why hes been saving it.

 

[sam9]

"There is a short paragraph about caps in his amp essays. You are, however, excused for missing it as the essay makes such a hilarious reading that one can be easily distracted. It's even funnier if you've ever listened to a Carver amp."

Yeah. The paragraph on caps was about the only one I was comfortable with, but was essentially "old news" . While the "down-converter" appearently functions as advertised (after all the do seem to generate substantial output from a fairly lightweight box) the explanation seemed pretty murky and appeared to defy Ohm's Law in some respects. Anyway this is all off topic.

 

[lucpes]

I experimented with several types of caps for bypass in power supplies, and I found out that sonicly I got the best results using el cheapo mylar 100nf /100V. Ceramics got me no big deal, mettalized polypropylene or MKP, MKS, MKT, FKP etc resulted in congested sound but these seem to work very well on everything (I used them for bypass in CDP, amp, even in speakers over some bp electrolytics)

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[svendesign]

capacitors

well... here are the considerations you should make when selecting capacitors...
first of all... what function is the capacitor serving?...you shouldn't use a film cap if you are dc blocking... because film caps aren't polarized. if you are just filtering a power supply or power supply rails on the circuit then the type of cap is not so important.. in fact caps with poor high frequency response are preferable... just make sure you are operating within acceptable parameters for the circuit... proper voltages etc...

ok now if a cap is used in the audio path then you should select one that has low esr (equivalent series resistance) and one that passes high frequencies well... vishay/roederstein make great film caps for use in the signal path..
their polyester and polypropylene caps are excellent.. if you need a larger value poly film cap then you can use a nichicon 105c rated electrolytic bypassed with a .1uf poly cap... this will take care of the high frequencies.
silver mica caps are good if you are bandwidth limiting an opamp...
(a compensation cap in the feedback loop).

orange drop caps are a bit dirty sounding, same with the siemens polyester caps... and most of those epoxy dipped film caps are not great either... it all depends on your application though.. sometimes it might be preferable to add a little grit to the sound... especially if there isn't so much high frequency content in the signal... as in electric guitar and bass equipment.