is this true about capacitors????

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prorms

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#1
is this true about capacitors????

Electolytic and tantalum capacitors have very poor audio characteristics and should not be used in the audio signal path


1 been the best for audio



1 polytetrafluorethylene (Teflon) capacitors
2 Polystyrene (styrene, styroflex, or styrol) capacitors
3 polycarbonate capacitors
4 polypropylene capacitors
5 Polyester (Mylar) capacitors
 
#2
It depends on where and how they're used. There have been some VERY highly rated amps that have used electrolytics (usually aluminum, not tantalum) in the input and feedback paths. Since power supply caps are nearly universally electrolytic, the signal passes through them, too.

Tantalum caps are much more problematic- see, for example, John Curl's paper in Audio.

Some designers feel that an aluminum electrolytic ANYWHERE is anathema. Others don't. That's why the discussions get so heated.
 
#4
Polycarbonates are good for sample-and-hold circuits, averaging (integrating) for RMS converters, oscillators, filters but they rank below polypropylene IMHO.

Styrenics are great for filter circuits, decoupling, etc. but are low in terms of popularity because they can't be "reflowed" unless you want a pile of goo on your PCB.
 
#8
Polymer caps would be things like the Oscon caps. They have better HF performance and lower esr than regular electrolytics, but aren't available in high voltages that I've seen. They seem to have the same audio problems as other electrolytics, and I avoid either, except in places where large values can't be avoided. They do work very well as the energy storage caps on low voltage signal boards, though you still need small ceramics or films next to the active devices. I wouldn't be too paranoid. If a preamp needed a 2uF coupling cap, I'd absolutely go with polypropylene. OTOH, if you needed 20uF, an electrolytic would be in order.
 
#9
How about the test setup?

gtforme00 said:
Tantalum capacitors have measurably high distortion products in the audio range when used as coupling capacitors.

An externally hosted image should be here but it was not working when we last tested it.


Here is one source for this information, although they do not include the exotic types you listed.
http://www.electronicscomponentsworld.com/articleView~idArticle~72992_8774533131512008.html

Regards,
David
Click to expand...
Can anyone explain how the test setup really looked like? Just inserting a cap and get 1% distortion? 😕 :scratch: I have read the pdf but somehow I have missed this information.
 
#10
Hi

I just found this interesting paper. It's kind of technical, but so far, most of it makes sense to me, haven't finished it yet.😛 This paper has better visual references and is easier to understand. Somewhere I saw a paper with DA values for different electrolyte materials but now I don't remember where. Maybe it was Mr. Curl's paper.:dodgy:
IMHO, polystyrene is the best but I haven't seen any in values above 10nf. Next on my list is polypropylene. I have a couple of 20uf polypropylene caps around here somewhere. They are axial at about 1"D X 3"L, and a cost of about $15 each.:xeye: I use 1uf polypropylene for my input caps. Third on my list of options is Teflon. COG chip caps aren't too bad either but exist only in small values, pf's. I like these for compensation. I try not to even fool with the others for signal purposes.🙂
 
#12
The most favored caps like Teflon and polystyrene have very low DA and DF, but I don't think anybody has specifically correlated DA or DF with sound quality. One thing I will stick my neck out on is that if you size the capacitor such that it has near zero signal voltage across it, it can't have much effect on the sound. In fact, if you can measure a significant signal across it because of either type or value, that's a bad sign and a better choice should be made. Obviously filters live in that region by design and caps should be chosen even more carefully for RIAA networks and both active and passive speaker crossovers.
 
#13
one caveat for teflon.... teflon materials have dielectric constants that have sudden shifts with temperature, some of them within the "room tepmperature" range. usually teflon caps have temp vs capacitance curves published in the data sheet. the sudden Kd shifts are due to minor shifts in the molecular structure of the teflon (the polymer strings shift their bonds at different temperatures).
 
#15
analog_sa said:



Never used Multicap RTX?
Click to expand...


No. But I'm very impressed with the price. :dodgy:

I do like these, but WOW :$: :bigeyes:

If only money really did grow on trees.🙄




unclejed613 said:
one caveat for teflon.... teflon materials have dielectric constants that have sudden shifts with temperature, some of them within the "room tepmperature" range. usually teflon caps have temp vs capacitance curves published in the data sheet. the sudden Kd shifts are due to minor shifts in the molecular structure of the teflon (the polymer strings shift their bonds at different temperatures).
Click to expand...


Interesting.🙂
 
#17
does any one on the board have experience with these caps?:

Elna SILMIC II, CERAFIN
Nichicon MUSE
PANASONIC audio grade caps

it is been conventional that electrolytics are used in the input and in the feedback side of a system........since because the availabilties or the prices of the said non polar caps are an issue.....nevertheless we have to go with the lytics.......just beware of chinese made ones.....

and in my case, at least I know that I'm using the ones with the brands ELNA OR NICHICON though general porpose types.....and at least I know that for sure as far as my ears are concerned chinese types are way way far from sonic quality.........

when buying these caps to the open market I would specify the brand.......

yet til then, still in pursuit to have those BOTIQUE types!


cheers
 
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