polyprop caps, metalized or foil?

[TomHinton]

Again, the problem is "what capacitor used where?" If cap A has 0R5 of ESR and cap B has 0R1 of ESR, there won't be any significant difference in a coupling use. Put the same caps in a high ripple current application (e.g., the input cap of a power supply filter) and the difference will be easy to measure- and possibly hear.

If ESR is constant and does not vary with applied voltage, how can it introduce distortion?

 

[SY]

It doesn't in the sense that I understand the meaning of "distortion." The ESR in this case will increase power supply noise since it's in series with the ripple current. Depending on the circuit and levels, the noise increase could be audible.

 

[simon7000]

It doesn't in the sense that I understand the meaning of "distortion." The ESR in this case will increase power supply noise since it's in series with the ripple current. Depending on the circuit and levels, the noise increase could be audible.

Sy,

One reply has already defined distortion as any signal that doesn't belong. I have mentioned various forms I have measured. The response was I have never heard them.

And why is it you continue? Logic is not applicable.

ES

 

[TomHinton]

So, it appears to be coincidence that low DA capacitors also exhibit lower forms of all the other possible sources of distotion.

 

[SY]

Tom, I'm not sure how you draw that conclusion. But in any case, the original question was answered: metal foil caps will generally have lower ESR than metallized film, all things being equal.

Ed, I live in the hope that logic and an analytical approach can be helpful.

 

[simon7000]

Tom, I'm not sure how you draw that conclusion. But in any case, the original question was answered: metal foil caps will generally have lower ESR than metallized film, all things being equal.

Ed, I live in the hope that logic and an analytical approach can be helpful.

Is hope logical? Actually it is!

 

[TomHinton]

Tom, I'm not sure how you draw that conclusion. /QUOTE]

An over generalization. I just finished reviewing the references mentioned above. I had previously overlooked the phenomenon of voltage coefficient, where capacitance varies with applied voltage. Turns out, film capacitors, especially polystyrene and polypropylene, have lowest voltage coefficirnt, as well as lowest DA.

 

[wintermute]

Again all the refered documentation is pre 2000!!! Is there no more recent research, as material science and capacitor manufacturing have moved on.

I won't repeat what others more experienced than me have said, but If you want something post 2000, then this site has Cyril Batemans most recent articles (originally written pre 2000, but updated and expanded in 2003). I'm reading the cap falicies one now, have not read the capsound ones yet.

Oh and earlier there was a question about whether the DA of film foil or metalised films was lower (whether it is relevant or not is up for debate) but in the jung article I linked, The polypropylene film/foil had slightly higher measured DA than the metalised film polyproylene, of course this could well vary from manufacturer to manufacturer, batch to batch or even cap to cap

Tony.

 

[Face]

I have never observed ill effects from the above sources. Most caps manufactured today no not suffer from these maladies, especially film caps.

I disagree as sometimes differences can be very obvious in spacial information.

If you're talking about standard film caps from major manufacturers (e.g., Wima, Panasonic...), then that's largely true. When you bring in boutique caps from "audiophile" sources, then many of these problems can appear.

Would you consider Bennic a major manufacturer?

I do agree that some "audiophile" sources are the worse offenders though.

 

[SY]

Would you consider Bennic a major manufacturer?

Don't know them. What's their market? Audio only or general electronics?

 

[jacco vermeulen]

Would you consider Bennic a major manufacturer?

Considering that the Taiwanese are a supplier for the audio main stream industry, and also do a couple of generic parts, Bennic still fits the bill.
Volume is another trademark key.