Briefly, how did you come to the conclusion it's the amplifiers?
Describe your Voltage Alternating Current system, Romex, metal clad, dedicated breaker, shielded power cords, balanced interconnects, star grounded, cable TV on the same circuit? How does you FM sound?
Describe your Voltage Alternating Current system, Romex, metal clad, dedicated breaker, shielded power cords, balanced interconnects, star grounded, cable TV on the same circuit? How does you FM sound?