Resistors Resistors are the best components, both because they have the least stray impedances and because they are available in a wide range of tightly controlled values. Surface mount resistors are made of metal film. Carbon composition resistors are obsolete except for high pulse power applications. They are expensive, less available, and noisy. Wire wound parts can be inductive, but handle the highest power levels.
Potentiometers can be carbon film, conductive plastic, cermet, or wire wound.
Conductive plastic is quietest. Avoid all mechanical adjustments if at all possible. A high Q means high quality. Copyright 1997 by William Chambers. Feel free to distribute this article and notice for non-commercial purposes.