Dual voltage equipment.

[bonenut]

I am looking at a Acurus a200 power amp that has come up for sale and the guy who is selling it has said its 120 volts. I googled images of the amp and see that it has two voltages ratings on the back with two fuse sizes( it does not have a switch) one says 120 volts 8amps sb( slow blow?) and then 230 volts 4 amps(250 volts)

has anyone any experience with this type of equipment and are there any issues with hum or anything else 50/60 htz related.

 

[newlash09]

I bought my amp in the USA. Which is 110V territory. And have carried it back to India, where we use 220V. The amp did come with a switch for the dual voltages. And after using it in both 110V and 220V , I haven't had any issues so far. So must be safe to change the fuse for the correct voltage .

Iam so confident of it, that iam getting a second amp from the USA now.

 

[davedotco]

Dual voltage is implemented in the transformer. The primary, the bit that gets plugged into the wall, will often consist of 2 separate windings handling around 115 volts with a current capacity of, say, 4 amps.

If they are connected to the mains in parallel, then the voltage remains at 115 volts but since each winding can handle 4 amps, this gives a total of 8 amps. If the two windings are connected in series, then the voltage is now 230 volts whilst the current remains at 4 amps.

In both cases the wattage is the same, 4x230 = 8x115, typical figures for a 1KVA transformer.

For this to be practical, you need to be able to physically swap the way the windings are configured, usually by an internal or external switch, though in some cases some simple rewireing might be required. it also explains why the fuse ratings are different, the 115 volt setting drawing twice the current of the one for 230 volts.