GND/Earth Wiring Management by Power Amplifiers - what is the royal Way

[tiefbassuebertr]

There are follow GND connections by discrete power amplifiers:

A: clean GND
1) enclosure/cabinet if it consists of metal
2) input resistor
3) RC highpass network of NFB loop
4) reference resistor of current source (LTP)
5) load resistor of predriver stage (second voltage amp)

B) dirty GND
1) Boucherot resp. Zobel network
2) load (loudspeaker)
3) neg. pole of power supply capacitor from pos. rail
4) pos. pole of power supply capacitor from neg. rail
5) center tap of transformer's secundary winding
6) main earth

If there are dual mono devices (i. e. separate and independend power supplies for both channels) the royal way for wiring is clearly to determine.

But what about normal power supply design's - i. e. one power supply and one cabinet for both channels?

In such cases I discover often very strange things like caps or resistors between the dirty and clean GND. Sometimes I observe serial resistors to some blocker capacitors.

The English brand "Moth" (Stan Curtis design), led the GND poles of the power supply capacitors about long separate cables to the neg. speaker terminals. Therefore the sound character was completly different to other models which uses exact the same power amp circuit topology.

Everyone of the individual commercial manufacturers (and diy'ers) here seems to prefer a different wiring.

Therefore the question for the royal way - thank you for your comments.

[fotios]

Everything you refer it is related with the effort of rejection of buzz, hum etc noise. If you could have a faraday case to include the amplifier modules, a seperate case to include the power x-former and a perfect power supply without ripple, then you would not need any of that.

Fotios