This is interesting though:

"One of the first major albums to make use of the Aural Exciter was Fleetwood Mac’s Rumours, recorded at The Record Plant in California in 1976. The lengthy overdubbing process had a negative impact on the condition of the 24-track master tape, and by the time the project had reached the mixing stage the worn tape had rendered many of the sounds dull and flat. This is where an enhancer such as the Aural Exciter came in to its own, restoring some life and top-end sheen to the tired sounds."