polarized vs nonpolar caps in circuit design

[JohnRoberts]

[quote author="bcarso"]I'm becoming convinced that people have used biased electrolytics* and shunned bipolars based on theory. And the theory is seductive and plausible. It just happens that (probably) with the double-foil integral construction bipolar 'lytics, it is incorrect. At least, based on measurements by the likes of Bateman, it is incorrect for minimizing distortion.

If one prefers the sound anyway in a given case, perhaps it is due to liking some 2nd. Perhaps it is due to the second harmonic at one stage cancelling the opposite polarity second in a later stage. Can't argue with what someone thinks sounds good.


*No one argues of course that allowing significant reverse-polarity bias on a polarized electrolytic is a good thing. That gives one distortions (and d.c. leakage) that are easy to hear and to measure. I'm referring here to the bias at the center point of two series-connected back-to-back polars in a bipolar coupling situation.[/quote]

Ok..after a little hunt (I'm a new guy) I found the articles but then I had to know who wrote them to read them so...... :?: I'm just going to cut to the chase and ask here about what I find confusing.

Is somebody suggesting that two series electrolytic caps connected in opposing polarity (+ to + or - to -) with that mid point properly biased with DC voltage relative to both ends, will generate audible distortion?

If both caps are properly biased and never reverse their terminal voltage they should be clean, or as clean as such things are. Putting them in series should not change that. Note: I'm not arguing that this is worth the cost of a resistor, but I don't see the harm from doing so.

JR

 

[clintrubber]

[quote author="JohnRoberts"]Ok..after a little hunt (I'm a new guy) I found the articles but then I had to know who wrote them to read them so...... :?:[/quote]
I'm sorry for that, hope the puzzle wasn't too much hassle. Rest assured, your little hunt will have just been a fraction of the scanning-effort :wink:

As said in the readme-file I didn't wan't to make it a complete no-brainer because those articles are still obtainable from EW+WW.

BTW, the pasword-answer is in the same message as I gave the link to the files in, but not in black. :thumb:

Regards,

Peter

 

[JohnRoberts]

Thanx... I'm a little busy doing stuff I should be this AM.

One reason to not use a bipolar for a manufacturer is it may be cheaper to just use two parts already in the system in a few locations than bring in and support another PN... Not such a big deal for DIY. The question of one being superior to the other does however merit discussion as the calculus then changes.

JR

 

[bcarso]

Bateman has, IIRC, somewhere, maybe even in the material under discussion, written to the effect that there is indeed a superiority to the bipolar of modern construction compared to back-to-back biased ones. He is a careful worker and as well I believe was in the capacitor business for a long time, so he carries a lot more cred with me than some random expert, let alone some loopy audiophool, and especially one hawking his pricey wares.

I know CB's results are counterintuitive. But intuition is not always reliable.

As expressed before I suspect the physics may pertain to reduced or at least different piezoelectric effects.

The effects in any case are small---look at how much trouble Cyril goes to just to get measurements. But then pursuing small effects is fun, if you have the time and inclination.

 

[JohnRoberts]

[quote author="bcarso"]Bateman has, IIRC, somewhere, maybe even in the material under discussion, written to the effect that there is indeed a superiority to the bipolar of modern construction compared to back-to-back biased ones. He is a careful worker and as well I believe was in the capacitor business for a long time, so he carries a lot more cred with me than some random expert, let alone some loopy audiophool, and especially one hawking his pricey wares.

I know CB's results are counterintuitive. But intuition is not always reliable.

As expressed before I suspect the physics may pertain to reduced or at least different piezoelectric effects.

The effects in any case are small---look at how much trouble Cyril goes to just to get measurements. But then pursuing small effects is fun, if you have the time and inclination.[/quote]

Thanks, I'll make the time to find that discussion (just not now). It is plausible that it is doing more than just preventing reverse conduction. This also suggests polar caps have the uncorrected manifestation of this mechanism all the time. This is certainly worth getting a handle on, since electrolytics are still widely used.


This brings me full circle back to "the best cap is no cap argument... "

JR

 

[ulysses]

[quote author="mediatechnology"]With really excellent "true" bipolars being available from Nichicon and Panasonic [/quote]
Where?
My primary reason for leaning away from bipolar caps is that I've never been able to find what looked like good ones. Look at Digikey for example. They carry a wide range of good Panasonic and Nichicon caps, but the only bipolar they carry is the Panasonic SU. I admit I have been lazy about this and I haven't investigated further to see if there are other ranges available elsewhere. But the SU doesn't look too impressive from the data I see. They aren't even specified in most of the relevant parameters. They look like cheap general-purpose caps to me. Are these things supposed to outperform the Panasonic FM and Nichicon HE? Or is there some other line available elsewhere that you're talking about?

 

[Svart]

Nichicon Muse ES bipolar: https://www.hndme.com/productcart/pc/viewCategories.asp?idCategory=40

 

[Svart]

I use the Nichicons, I think I mentioned that earlier in the thread. When you buy them in bulk the prices become very reasonable and competetive with good quality polar caps thus negating the cheaper-to-use-biased-polar-caps theory.

 

[Svart]

unfortunately the ES is much larger than a normal cap of the same size.

 

[ulysses]

It's pretty interesting to compare Nichicon's data sheets for the ES and KZ series (their "audio" capacitors) to their data sheets for the "HE" series. The HE's are rated far better for temperature and endurance, and that's about where it ends. Not because the "audio" caps are comparable - but because they don't list any important spex for them. Why wouldn't they publish the same data for these caps that they do for all their others? Is it because the "Muse" name and the gold-colored printing is all that's needed to draw in the audio market?

 

[Svart]

I have PW, HE, muse KZ and buse ES Bipolars in channels for comparison. They each have their distinct sound and I like each for certain things. I just happen to like the sound of the ES best, then I would say that the KZ and the HE are similar while the PW is darker.

Either way I still like the nichicons better than the panasonics any day.