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Zero Cool 14th January 2007 02:36 PM

Good John Curl Article on Capacitors
Maybe you guys already know about this article. I jsut found it and while it is mainly talking about Parasound amps. there is a really good section in the middle about capacitors! Very interesting read.


Ron E 14th January 2007 03:21 PM

There's not much to argue with, there. Have you read the Jung article?

roddyama 14th January 2007 03:41 PM


Originally posted by Ron E
There's not much to argue with, there. Have you read the Jung article?

Yes, Mr. Jung's and Dick Marsh's 1980 Audio Magazine article on capacitors should be the starting point on any discussion on how capacitors affect sound quality.

Zero Cool 14th January 2007 03:57 PM

I have read many articles on caps, but i do not think i have read the W.J. article. Thanks for the link, i see there is a great deal of good stuff there as well.


jcx 14th January 2007 11:11 PM

actually there is a point or two to argue

dielectric adsorption is very well explained by a linear model, so speaking of nonlinear "dielectric adsorption" distortion is a little misleading

linear frequency response "distortion" - deviations from the pure C transfer function don't appear to be anywhere near audible thresholds - and I mean even quiet adapted ears noise threshold, much less the ~1% of signal level that double blind listening tests seem to indicate as the just noticeable frequency response difference

Bob Pease' Capacitor Soakage" article is a valuable information source:,28,00.html

Dielectric Adsorption may correlate with other phenomena that are undesirable but audiophiles seem accept that it is proved that dielectric adsorption itself is a problem when the success of the linear model and calculable consequences of the linear model demonstrates that it is a audio non-issue

I'm not knocking Curl's comments in the interview so much as the continuing perpetuation in other audiophile write ups that the story is finished when they point to dielectric adsorption

serengetiplains 14th January 2007 11:31 PM

I don't think it accurate to say dielectric absorption is "explained" by a linear model---it *is* modeled with a linear model.

Dielectric absorption is, IMO, quite audible, in fact is an obvious-as-the-day sonic differentiator between capacitors. Pease's article is quite old. A better article---series of articles, actually---and one that documents (sonically relevant) IMD and THD test results on different dielectric types is Cyril Bateman's 2002 Electronics World series on capacitor sound.

jcx 15th January 2007 12:12 AM

when the modeled response fits the measured data to a high degree of accuracy we generally say that the the model "explains" the phenomena - a colloquial usage - not necessarily a deep physics based causal explanation but a quite good enough "explanation" for engineers to move forward with

I seriously doubt anyone hears the physical phenomena of dielectric adsorption - you are claiming to perceive an audible difference in some circuit including a capacitor that is reproducing some musical or test signal in the audio frequency range - and then attributing the perceived difference in capacitor’s “sound” to the single variable of dielectric adsorption - this is not a logically watertight procedure when the capacitors undoubtedly differ in dielectric constant, loss, electrodes, construction, physical size, thermal history, water adsorption, lead material, wrapper color…

Since the linear circuit model of dielectric adsorption does “explain” the phenomena well enough for Bob to show a correction circuit for sample/hold applications that improves the lesser performing dielectric to Teflon performance levels then I think it isn’t to much of a leap to ask if the linear model “explains” reported audible differences – and it does not

This failure of a good model of the phenomena of dielectric adsorption to explain an observation of different audio perception of capacitors with differing dielectrics suggests to me that there may not a causal link to dielectric adsorption itself and that time would be better spent looking into other phenomena (that may just happen to correlate with dielectric adsorption)

serengetiplains 15th January 2007 12:24 AM

Yes, yes, heard that before. If the clear-as-day audible factor is not dielectric absorption, it is, then, something in the neighbourhood of dielectric absorption, ie, something to which dielectric absorption very tightly correlates.

Bateman, a former capacitor engineer, would almost certainly disagree with your speculations regarding the sonic nature of dielectric-absorption-or-whatever-it-is-that-correlates-with-dielectric-absorption. Bateman, for his part, was, in writing his articles, just trying to be a good engineer furthering his science a bit.

jcx 15th January 2007 12:42 AM

single factor experiments are clearly out since we are talking different materials for the dielectrics

but a possible experiment would be to implement the linear multiple RC branch model of say a mylar capacitor with a literal implementation of the linear dielectric adsorption model using multiple polypropylene or Teflon Caps and quality resistors and abx compare them

the strong presumption from established double blind frequency response testing thresholds is that there would be no audibly perceptible differences for common linear coupling/filtering capacitor applications

serengetiplains 15th January 2007 12:51 AM

Read Bateman. Eye opening stuff for those needing measurements to correlate what the ear, in this realm, can easily hear.

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