Many different constructions of electronics elements are used inside audio electronic circuits, for instance capacitors can be electrolytic, tantalum, silvered mica, polypropylene, organic electrolyte, and others. The fact is that each different construction produces a different influence on sound by means of introducing a small measurable distortion.
Some types of distortions are more noticeable than others. Some distortions we do not mind as much because our hearing does not notice them. In any case, it is evident that electronic components used for audio applications must be carefully chosen for their sonic performance.
Foundation #9: All parts used in audio electronic circuits must be selected for their sonic performance in order to produce the best audio results.