i seem to get the idea that the HK's voltage can be changed by changing a fuse.
http://forums.audioholics.com/forums/amps-pre-pros-receivers/85279-can-harman-kardons-new-$1000-avr-3700-hold-its-own.html#post965210
i opened my 1650. the writings near that 6.3A fuse says:
USA: T 6.3A L 250v
Eur: T 4A L 250v
questions:
1) is it as simple as changing that fuse?
2) if this truly was a switching power supply, plugging this into 220v (temporarily) should work right?
3) how do i know if it's a switching power supply?
No! You have this wrong. The fuses change with the voltage bused as the current changes. So the lower the voltage, the higher the amp rating of the fuse for the same protection.
A switching power supply does not mean you can use a variety of voltages. A receiver will not have a switching power supply anyway.
In order for your receiver to be used on your 220 Volt supply, the it has to have a tapped transformer, and you would have to solder the input wire to the the correct tap, and may be also change some links on the transformer. In general receivers do not have tapped transformers, as we live in money grubbing times.
Most likely you will need and external step down transformer.
