Passive parts: Do they make a difference ?

For those of you that are "curious" or "unbelievers" about the effects that various grades of passive parts ( capacitors, resistors, diodes, etc... ) play in the sound and measurable performance of a circuit, take a look at this article by Bob Pease about dielectric absorption in capacitors on the National Semiconductor website.

Bob refers to "soakage" of the capacitor ( the cap is "soaking up energy" rather than passing it on ) instead of dielectric absorption, but it is the same thing using different terminology. While the article is technical by nature, one with a basic understanding can simply view the graphs and O'scope photo's and see that there truly are very measurable differences in performance amongst passive parts.

This article goes on to demonstrate how one can use lower grade passive parts and still obtain good performance, but additional corrective circuitry becomes a necessity if one takes that route. In audiophile lingo, this would be akin to building a sloppy circuit and then resorting to using tons of negative feedback to correct it. As such, the "most correct" approach would be to use higher grade parts to begin with. The end result of such an approach would be a shorter signal path with less potential for signal degradation to occur.

As a side note, Bob talks about the differences in how circuits lock or sample in an ADC ( Analogue to Digital Converter ). The same basic circuits / comments / observations would apply to a DAC ( Digital to Analogue Converter ) as they are basically the same circuits working in reverse.

Other than that, i'd love to see others contribute locations of other sites that have various points of view / comments on the "quality" of "passive parts". Obviously, this post and the info contained in the link are also open for debate, so fire away with comments as you see fit : ) Sean
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