If I buy a Hi-Fi component from the US or Europe will it work contained by Australia? will the power requirements be the same? Will I
will the power requirements be the same? Will I hold to get the power cable changed over?
Answers: Australia uses 240 volt, 50 Hz. electrical power. Hi-fi equipment sold in the US may or may not support 240 volts; read the specifications for input voltage cooperatively. If it's 120-volt only, it will run on a step-up transformer. European equipment roughly supports either 120 or 240 volt supply but again, read the specifications.
There could be one further problem if you want to include a turntable. The difference between 50 and 60-Hz power is not important on most equipment, but a turntable sold surrounded by the US will run more slowly on a 50-Hz supply. (The same might be true for reel-to-reel tape recorder -- not sure, so read the specifications.) Hi-fi turntables may come with for a while adapter that you substitute under the platter to modify the rotational speed depending on the frequency. Check carefully.
Finally, Australian AM radio stations operate on a 9-kHz low spacing, and US AM stations are 10 kHz apart. If you buy a digital radio tuner in the US that does not support both formats, you'll not be capable of tune in most Australian AM stations. Better tuners own a switch to change the spacing. At the risk of sounding approaching a broken record, check vigilantly.