Using US amps in Aus

[jesse]

Hi,
I'm not sure whether this is the right board to ask this in, but it looked the closest. I'm just wondering whether its possible to use US amps in Australia, given that the US uses 120V power and we use 240V? Would a step down transformer fix this or would it just create more problems? I ask because I really want a Pignose G40V but I can't seem to find them anywhere in Aus. Any help would be greatly appreciated.
Thanks,
Jesse

[JohnH]

Hi Jesse - welcome to GN2. im glad to see another from Australia. I live near Wollongong NSW.

I used to live in the USA (L.A. to be exact), and came back here with a heap of electrical gear. No guitar amps, but we did bring stereo gear.

It should be fine with a mains step-down transformer, we use several of them around the house. The main thing is that it needs to have a power rating which is comfortably more than the power consumption of the device, say twice. Remember, with an amp, the power is not the output power but the power consumed. eg, my 40W Marshall uses 150W, according to the back plate. So for my amp I'd be wanting a step down transformer of at least 300W, and that may take some searching, plus it is a fairly heavy thing. I dont know where to get them here, maybe try Jaycar.

That plus the cost of shipping an amp from the US would perhaps make it better to pick something available here

Another possibility (I dont know about this one), would be if the mains transformer in the amp already had a 240V tap

Good luck

John

[jesse]

Thanks heaps for your advice John.
It's good to know that it would work, but you might be right that it'd be easier and cheaper to just get something available here. I'll keep looking into it...
Thanks again,
Jesse

[ChrisK]

Another possible issue might be the line frequency. The U.S. uses 120 VAC at 60 Hz. I believe that Australia uses 240 VAC at 50 Hz.

If this is the case, since 50 Hz transformers use more iron (core size) than 60 Hz transformers for the same converted power, operating a 60 Hz unit on 50 Hz will cause more power transformer heating. The heat issue with transformers is the wire insulation as well as the core laminate temperature ratings. This goes directly to the safe operating power ratings.

Since the bulk of the input power to a tube amp "goes up in heat", one should be careful since even a substantial reduction in output power (such as cutting it in half) makes little difference in total input power.

I don't have any quantitative metrics for derating 60 Hz transformers, but one should be aware.