I have a Denon AVR 2312ci hooked up with 2 woofers. All works great til I hooked up the 12v on/off leg on the Yamaha YST-FSW050 to the control on the Denon. A fairly loud hum is introduced. I've tried adding grounding wires to the chassis of each and both, even hardwiring the two frames together. That reduced the hum about a third, but still objectionable. I've changed the control and the rca cables .
Has anyone any other ideas? Is it possible to put an in line filter on the 12v cable?
