Spectral preamp picking up a radio station

I have a friend with an all Spectral pre/amp system (25 years old). When I was listening to his system, I can hear quite distinctly  some radio station playing from the left speaker even though there is no radio on in the house. We were playing an album, so it can't be the DAC. This started happening within the past year or two. Could a malfunction in the preamp cause this?