When you disconnected the interconnects was it at the amp or the source end ? You should have disconnected at the amp end to make sure the interconnects were not acting as antennas. Not all interconnects are well shielded, but you can build very good ones quite cheap.
I doubt your power cable will help since none of the wire between the circuit box and the outlet is shielded. You're right to be thinking about a power line filter to remove interference from the mains.
I would try to home demo a power conditioner to make sure the amp is not susceptible to air-borne RFI interference. RFI can get into the amp from the power supply OR just from the air into the preamp section of the integrated amp. Just hope it's not the latter. A power conditioner may not help ... so I would try before you buy.
Good luck.
I doubt your power cable will help since none of the wire between the circuit box and the outlet is shielded. You're right to be thinking about a power line filter to remove interference from the mains.
I would try to home demo a power conditioner to make sure the amp is not susceptible to air-borne RFI interference. RFI can get into the amp from the power supply OR just from the air into the preamp section of the integrated amp. Just hope it's not the latter. A power conditioner may not help ... so I would try before you buy.
Good luck.