The Sunfire Corporation is another one of Bob Carverís children. His tracking down-converter that was used so successfully in his TrueSub amplifiers is a very clever design. We are very capable of repairing yours. Please send us only the amplifier module; we have never seen a woofer go bad.
This amplifier uses a tracking down-converter, as well. That works perfectly, but the linear power supplys are known for having bad capacitors, which cause a hum in the channels. We should be able to take care of that problem for you.