What we have done here is taken a commercially designed mains filter kit and modified it ever-so-slightly to make it more acceptable - not only for Australian wiring rules and practices but also more acceptable as far as the end user is concerned.
Fig.1: the circuit consists of two LC filters and a voltage-dependent resistor. All sections of the circuit are at 240V so take extreme care.
As well as making a few mechanical changes to the circuit
(which we will cover shortly), we also added a four-way powerboard so that the filter goes between the mains plug and the four outlets. That way, all (or at
least four!) devices could be plugged into clean mains.
Incidentally, there is nothing to stop you using a six-way or
even eight-way power board if you wish. But four-ways are now really cheap - often less than four bucks each at Woolies (and no doubt other stores!).
The documentation and PC board both state a maximum loading of 2300W - this would be more likely 2400W in Australia with our 240V system. But if your hifi system draws anything like 2kW, please let me know before you turn it on so I can leave town!