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
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...."
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.
Pbb: If a circuit will not "lock" properly due to improper wave-shaping and / or losses within the circuit, don't you think that the results would be audible ? Obviously, one can force themselves to believe that once the circuit "locks" that any sonic differences would be undetectable, but that would strictly be a matter of personal belief based on pre-concieved ideas.

Audible differences of 200 - 300 millibels in amplitude or frequency response have been easily detected under controlled and repeatable conditions. For those that aren't electronically inclined, that is .2 - .3 dB's. This does not mean that everyone can hear or detect such differences but that it "could be" audible to those with good ears that know how to listen. Bare in mind that i'm not only talking about differences in amplitude but those of linearity ( frequency response or "frequency abberations" ) also.

As such, there is more to being a good listener than just "hearing". As an example, a layperson HEARING an engine run might think "it runs good" while a skilled mechanic could be LISTENING to that same engine. Due to the differences in background and skill, the mechanic might be able to discern that the timing is slightly off, resulting in less than optimum performance. This is much the same reasoning that most audiophiles discount the validity of blind listening tests performed on unskilled listeners. Should anyone expect the same level of quality / performance when asking a novice to do the same job as a pro ? I think not.

For the sake of clarity, i don't think that being an audiophile automatically qualifies one as a "skilled listener". Because one chooses to / can afford to dine in expensive restaurants does not make them any more a "connoisseur" than one that chooses to / can only afford to eat fast food makes one a "common-sewer". Sometimes, such matters are nothing more than a difference in personal tastes, convenience or priority.

Eldragon: I don't doubt the info that you posted in the least. It was experience after experience like those that you mention that drove me to learn about speaker design and experiment with parts quality. When one finds out that you can buy a better driver with a retail cost of $15 than what a well respected manufacturer is using in what was their top of the line speaker, it makes you sick. This is not to mention the use of wire that wouldn't be suitable for use in hooking up a door bell !!! All of this tells you that one can do much better on their own for less money if they are willing to take the time and have the equipment to do so.

My personal findings are that the majority of companies that manufacture and market raw drivers for public consumption do better at driver design than they do at building a finished product. As such, i would not personally buy a speaker system from Dynaudio, Focal, Morel, etc... even though one would think that, since they build the drivers, they would know how to get the best out of them. My experience differs with that point of view, especially given the costs involved with most of their models.

To be fair, i might feel the same way about other companies that manufacture their own drivers but do not market them ( B&W, Thiel, Bose, etc*...) but have a harder time finding that out. The difference is that i can only go by what my ears tell me with these since i can't review the quality and electrical specs of the raw drivers themselves. While i would always prefer to use both my ears and specs ( if available to me ), the previously mentioned companies ( Dynaudio, JM Labs, Morel, etc... ) allow me to do the math and compare alignments / crossover points and slopes, etc.. right off the bat.

By doing the math, i've found that quite a few of these companies use box sizes that are less than optimal, poor selection of vent size, less than optimal crossover points, etc... In some cases, i've seen drivers used in a vented box that would work best in a sealex box, etc... On top of this, they sometimes take premium drivers and couple them with less than optimum support components ( box construction, damping material, cabling, capacitors, resistors, types of connections, etc... )This is the kind of stuff that makes one scratch their heads and wonder why they bothered with using better quality drivers to begin with...

Marakanetz: If we could apply all of the knowledge that we have in our heads learned from others' experiences, we would all have the finest quality systems in the world. Unfortunately, accumulating knowledge and transferring that from our heads to our hands can sometime be quite time consuming. Making the time to do so is typically quite worthwhile, but due to scheduling conflicts and / or lack of organization, it becomes hard to do. I'm sure that you can relate : ) Sean

* Mentioning Bose in the same sentence as B&W or Thiel does not mean that i consider them to be of the same quality. What it does mean is that these manufacturers build their own drivers yet do not publish specs on individual drivers on their own. As such, one is left to discern how well they work as on the whole when fully assembled in a system. It is possible that some of the drivers made by any of these companies could be superior to those made by their competitors BUT the implimentation of the product is not up to snuff. This would result in one drawing an incorrect conclusion about the driver itself when the problems noticed were due to poor design / engineering of the support components.
Sean: an interesting question begs to arise - give me a box full of the best passive devices, and, if I were to build an amplifier (a rank amateur, me) how would it sound next to an amp built by, say, Nelson Pass with Radio Shack rejects? I do not doubt for a second that the quality of passive parts not only begets measurable effects but sonic ones as well. But I also believe that the ultimate determinant is the thinking and skill of the designer. What is described in the article is nuts and bolts physics, but an element of artistry has to be involved; almost crucial - a designer has to "read" the circuitry the way a conductor reads a score. A mix of artistry, engineering (manufacturing) and components, I believe, have to be synchronized to get the best out of an audio product.
I have zero experience building gear as a hobbyist, so although I never doubted in theory that passive parts could make audible differences, it was only when I got a phonostage with plug-in sockets for changing loading resistors that I was able to hear this for myself. After settling on the best loading value by substituting with decent but inexpensive resistors, I got some recommended premium resistors in that value. The sonic difference was far greater than I had imagined it would be. A resistor seems like the simplest of parts, and I wasn't sure exactly what I would hear when I sat down to do comparitive listening tests - I was mentally preparing to have to strain to hear any difference at all, maybe a touch more transparency, I guessed.

The expensive resistors did offer that (more clarity and resolution), but what surprised me most - and I was totally not prepared for - was that the premium jobs revealed the cheapies as being not tonally neutral. I don't know whether I would have even heard the colorations of the inexpensive resistors had I not done the comparision, but if I had, I sure wouldn't have thought to lay it at the feet of one measely resistor per channel. And the transient articulation, dynamics, and imaging palpability improved too. After getting a taste of the better stuff, the cheap resistors (and they weren't bottom of the barrel by any means) just sounded a distinct bit veiled and artificial in comparision - they simply didn't get out of the way like the premiums did. Now multiply this over the number of resistors in an entire circuit (OK, I know it's not quite that simple, but still...) and you begin to see how this sort of thing could matter quite a lot.
Gs: I agree wholeheartedly regarding the crucial importance of starting off with a well designed circuit and that designing such a circuit is somewhat of an "art". Having said that, i've heard some very good measuring and sounding circuits sound even better after "high grade" parts have been substituted.

As to your question about building an amp with high grade parts using less than optimum circuitry against an amp with mediocre parts and top notch circuitry, i would take the latter for multiple reasons. First of all, one could always upgrade the parts of the better circuit. Secondly, the "home-brew" amp might sound even worse than expected due to the ultra-revealing nature of the higher grade parts. As such, putting "top notch" parts into a horrible circuit can make things worse.

Only problem here is that many of the noticeable deficiencies that we hear are not so much from the poor circuitry but from the specific passive parts used. As such, if one had a product that was questionable in terms of whether it was worth upgrading or not might be a crap-shoot. Is the "mediocre" sound that you are hearing due to poor parts selection, poor circuitry or a combo of the two ?

Only way to really find out is to do the modifications on a step by step basis in a manner that is easily reversible. Using this approach, one can keep track as to what mods were more worthwhile in terms of sonic improvements for the money. Some changes will be noticeable on their own whereas others seem to be more of a cumulative effect. If one went whole hog and used truly great parts throughout the entire circuit and the sound was not what one expected, the limiting factor would probably be the lack of a quality circuit design.

One of my friends ( Lou ) who has done quite a bit of parts swapping has told me that using higher quality diodes / bridge rectifiers and swapping out the OEM caps and installing Black Gates will typically make a very noticeable difference in liquidity, transparency and "more correct" tonal balance. He thinks that this approach offers a far higher "bang for the buck" than doing any other modifications to the equipment. While i don't doubt this, i think that most products can benefit ( due to cumulative effects ) by taking things a step further and changing the wiring, jacks, increasing filter cap reserves, changing the jacks, etc... as needed. Obviously, some products use a higher grade of parts to begin with than others, so some of this may not be worth doing at all. As such, you have to assess each unit on its' own merits and procede from there. Sean