In most components the circuit ground is directly connected to the chassis. And the chassis is connected to power cord ground. Pretty sure all common ground amplifiers are set up that way. You would not want to try your RCA trick with a non common ground amp.
So what you are proposing technically not make any difference, but anything goes with audio. According to the books what you are doing should make the system sound worse. You are supposed to ground everything in a component to a single point on the chassis via a "star ground". Grounding to different points is supposed to do bad things to the sound.
I would take a peek inside and make sure the circuit ground is connected to the chassis somewhere. The power cord ground should be connected to the same point. Then even though it goes against conventional wisdom......if your system sounds better go for it.
So what you are proposing technically not make any difference, but anything goes with audio. According to the books what you are doing should make the system sound worse. You are supposed to ground everything in a component to a single point on the chassis via a "star ground". Grounding to different points is supposed to do bad things to the sound.
I would take a peek inside and make sure the circuit ground is connected to the chassis somewhere. The power cord ground should be connected to the same point. Then even though it goes against conventional wisdom......if your system sounds better go for it.