It may be your cable routing, particularly the phono cables. Try moving them around while a record is playing.
Phono cables function as an antenna, obviously enough, and even though they are shielded, in some RF-heavy areas (like mine in Montreal) this isn't enough to keep them from picking up a signal strong enough to be heard when it goes through your preamp's high-gain phono section.
With luck, reorienting the cables, you'll be able to place them in a null point for RF reception. The opposite of what you'd do with an FM antenna or a pair of rabbit ears.
If that's not enough, you may have to look into moving your system within the room, adding shielding to the small-signal high-gain components or even changing some of your gear.
Phono cables function as an antenna, obviously enough, and even though they are shielded, in some RF-heavy areas (like mine in Montreal) this isn't enough to keep them from picking up a signal strong enough to be heard when it goes through your preamp's high-gain phono section.
With luck, reorienting the cables, you'll be able to place them in a null point for RF reception. The opposite of what you'd do with an FM antenna or a pair of rabbit ears.
If that's not enough, you may have to look into moving your system within the room, adding shielding to the small-signal high-gain components or even changing some of your gear.