Futurist Ray Bradbury's 1952 book, A Sound Of Thunder, first proposed the idea of what later became known as The Butterfly Effect.
Small changes in one part of the world create larger changes elsewhere.
This theory applies to hifi systems as well as weather prediction. In a complex electronic instrument everything is tied to everything else. A small change in one area, affects everything else.
It's difficult, if not impossible, to isolate a feature in one product and apply it to another, expecting the same result.
Take for example Power Plant AC regenerators. I am often asked why, if we're generating new power from old, the incoming AC power cable might matter. Sure doesn't seem like it should. Right?
Wrong. The problem is, we're assuming too many things. We're assuming it's a perfect process with an unlimited source, when neither is true.
Or, take for example the Digital Lens. Once digital audio is passed through the Lens it's rebuilt without any trace of original jitter or timing issues. Therefore, every instance of the Lens should always produce perfect digital. Right?
Wrong. Again, we're assuming it exists in a perfect vacuum—without affect from power supplies, radiated noise and other artifacts.
Here's a third example. Equalizers. If our systems has a frequency response issue we should be able to correct for it with an equalizer and make the sound perfect. Right?
Wrong. While frequency issue might be solved, the added circuitry and phase shift required to fix the problem adds yet another variable detracting from the sound.
Everything in our systems is interrelated.
We can't take a step in one direction without upsetting something else.