The perceived sound quality of an amplifier is not determined by its color, but rather by its internal components and circuitry. However, some people believe that black amplifiers “sound better” because they create an “ominous impression” and have “deeper bass,” while others choose silver for preamps and source components to better see the knobs and controls in low light.
Some audiophiles express a preference for silver because it allows them to see their equipment. Others feel that black components disappear more easily and don’t go out of style. Ultimately, the choice between black and silver is a matter of personal aesthetic preference.
FWIW, I prefer a black faceplate.