Does parts quality really affect performance?

Paul McGowan writes ....

When this particular Fact or Fiction proposition was originally proposed I passed it over because its answer seemed so evident. Yes, of course, parts quality affects performance. It’s a no-brainer, right? Maybe not to everyone.

We can easily agree that low tolerance parts that change value depending on temperature or variability in their construction can measurably impact delicate crossover and filter circuits, increase distortion, and upset the balance of essential circuitry, but that is not what I mean when posing this question. No, I am referring to the actual materials and technologies behind the building of those parts assuming tolerances and variabilities are the same: the type of film in capacitors and resistors, the materials in dielectrics, the base metals in connectors and wires.

To our engineering staff differences in capacitor construction, for example, are so obvious as to be classified as night and day: a REL Cap vs. a Jantzen, or Mundorf of the same value and materials. This is a particularly difficult problem when we are working on building equipment to a price point. We’re unwilling to compromise sound quality and thus we have to apply inordinate amounts of clever combinations of quality parts and circuit tricks to afford what we want. It may mean that if we cannot afford the quality of a particular drop-in-easy coupling capacitor required to achieve the performance we want we will have to spend another week of engineering time designing a lower cost DC servo circuit instead.

I remember well when we first launched Ted Smith’s amazing DirectStream DAC for the first time we spent a similar week’s worth of engineering time choosing whether it sounded best to use thick or thin film SMT resistors in the output attenuator. Common wisdom is that thin film SMT parts sound best and that’s what we populated the first production run boards with, but something just wasn’t right when we activated the attenuator. After hours and hours of work we discovered in this one instance, it was thick films that won the race. We had to hand remove (using a microscope for some of the techs to even see them) the parts and replace them with thick films before we released the products.

So, yes, parts quality affects performance.