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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sean
Nice to read right at the top of your post that this fellow considers that passive components of better quality play a role in the "measurable performance" of a circuit. I guess this means that it is not pure voodoo amd mumbo jumbo after all! I will read the article linked, the minute I get a minute. Thanks.
Sean, friend of mine 'gutted' the Dynaudio 3.3, (think $7K a pair). What he found was cheapest sandcast resistors, Bennic and Solen caps, and plain ole' air core inductors. He replaced most(mid high) of the caps with Hovland, and he claimes that sound better!?
I read once, Sid Smith from Marantz said: "Good topology with CONSERVATIVE use of high quality parts...."
Sean,
It's realy realy great that we do have that luxury of choice of elements here.
Not often larger circuit complexity means longer signal path and proper design is valuable even with expencive parts since someday they will deplete and won't perform as they were new(well, some say broken-in).
That certainly with no less degree applies to active elements that by default are all not perfect and need some applied complexity to be stable.

Great article! Still reviewing thoughts of compensation to apply to my DAC if I will spare the time.