Get a three prong male "Receptacle Tester" from Radio Shack or your local hardware store for $4 to $8 cost. Check all your outlets to make sure they are wired correctly. Sometimes the Neutral & Ground wires are reversed causing a ground loop problem due to ground differential. All the gear works with the wires reversed, but you get the hissss.
Step two is to use a piece of wire to connect the component chassis together to help equalize their ground potential. Connect the wire from chassis bolt on component A to a chassis bolt on component B. If the hissss goes down you can come back and fashion a better chassis-to-chassis ground jumper with the advice of a pro.
Defeating the ground wire on the AC cord with a "cheater plug" can be dangerous. Sometimes that ground wire is used to ground out voltage that may be present on the chassis. Without the ground wire the voltage is still there waiting for a "path". You could become the path by touching two components at once and get yourself a little love shock or in some cases a real doozie up to 120volts.
Step two is to use a piece of wire to connect the component chassis together to help equalize their ground potential. Connect the wire from chassis bolt on component A to a chassis bolt on component B. If the hissss goes down you can come back and fashion a better chassis-to-chassis ground jumper with the advice of a pro.
Defeating the ground wire on the AC cord with a "cheater plug" can be dangerous. Sometimes that ground wire is used to ground out voltage that may be present on the chassis. Without the ground wire the voltage is still there waiting for a "path". You could become the path by touching two components at once and get yourself a little love shock or in some cases a real doozie up to 120volts.