So Dr. Bews - how important are passive components in amplifier design?
The selection of passive components is a very important factor in the design of an amplifier. Subjective evaluation is essential in this selection, together with reliability. It has been found that the most optimum component for a particular circuit location may differ from every other similar part. As an example, it’s not normally possible to use the same resistor type for every resistor within an amplifier, each position must have a type that produces the best subjective results. This process also applies to the choice of capacitor used within the circuit and any capacitor used as a power supply decoupling component. The iterative procedure is very time consuming and means that product development is slow and methodical. There is no easy solution to this problem, but perseverance does bring its rewards of better sound quality.