Here is a very good schematic showing a tipical power amplifier grounding system. I have tried it ina many of my projects and it works every time. No hum, no ground loops no noise. Dead silent. Of course a proper power supply routing on the main PCB is critical. If done properly some very very high performance could be achieved.
Update 18.10.2014
The schematic was proposed by D. Self in his book “Audio Power Amplifier Design”. For any further info, please check out his work.
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The diagram is from Doug Self’s Audio Power Amplifier Design book.
He should be credited.
Girish Bhalla
The grounding circuit I read in your website it,s good , I have a suggestion , let the ckt. be as it is except one change the shielding of shielded cable is to be connected directly to the mains ground. Thanking you, With regards.
Girish Bhalla
The signal cable shielding is that of the input signal cable from the mic.,Tape,mag pickup(gramophone),CD/DVD player output.radio (AM/FM)Detector output, to the input eg. of an audio amplifier. Girish Bhalla.
Girish Bhalla
One of the sure methods to reduce hum and hiss pickup is to attach a 3(three) core audio shielded cable or 2 no.,s of 2(two) core audio shielded wire for stereo audio amplifier input. The two core wires carry the audio signal while the shielding only after getting connected to mains ground directly, will shield the signal from external hum and hiss noise(50Hz-60Hz).
d.arther
how many of you are build a mono amplifier?
this circuit is of no use if your have more than one channel…