Sure, as long as you understand a few basic technical details.

Basics

You can use any voltage thing anywhere you like, as long as the voltage and current requirements are met. For that, you’ll need to know all the relevant voltage and power consumption ratings and then select a suitable step-down (or step-up transformer).

For 100V Japanese equipment that cannot be reconfigured for local voltage, you’ll need a quality step-down transformer with the correct power rating and voltage. Such a step-down transformer should be sourced from a quality local manufacturer like Tortech. It should be rated to deliver between 1.5x and 3x (or more, just not less) the rated maximum continuous power consumption of the attached equipment. It must also deliver precisely the voltage your equipment requires, no more, or less.

100V-rated equipment needs a 100V step-down transformer, rather than the 110V or 120V offerings commonly available from places like Jaycar. Make sure you know which one you need, as indicated on the placard on the rear of your equipment. Avoid cheap Chinese transformers as these are usually incorrectly rated for voltage and often significantly under-rated for power.

Special Cases

If you have a powerful amplifier, you’ll need a big step-down transformer and these can be expensive. An amplifier rated for 500W maximum power consumption should be matched with a transformer rated for a minimum of 1 – 1.5kW on a 100% duty cycle, more if possible. That’s a hefty transformer and it won’t be cheap.

The high rating is necessary to minimise power supply source impedance and transformer core saturation. This will maximise amplifier performance and ensure the transformer does not overheat during normal use. Because hefty step-down transformers can be heavy and expensive, whilst it is possible to use them without penalty, amplifiers are the least well-suited for use with step-down transformers. This limitation especially applies to big, heavy current-hungry class A and AB amplifiers of high power output.

For low-powered equipment like turntables, DACs and preamps, smaller step-down transformers work well. A moderately sized transformer will safely be able to run several low-power devices. Just make sure that the total continuous power consumption of all the connected equipment is comfortably exceeded (1.5x to 3x, or more) by the continuous maximum rating of the stepdown transformer.

Highest Voltage

Something you may not realise is that it is always best to run high-power, high-current devices like amplifier on the highest voltage you can set them to, ie 240V. This is because at 240V the current requirements are less than half what they are at 100V. That means less voltage sag at the outlet, lower wires losses due to resistive heating and reduced dynamic effects associated with modulation of the power supply rails due to excessive current draw. Many extreme systems in countries with 100 or 120V mains will be wired to accept 220 or 240V for this reason.

Warnings

You must never plug equipment rated to run on 100V or 120V into an Australian 240V mains outlet unless it has been set to run at 240V.

Failure to adhere to this warning will almost certainly result in the death of your equipment and it may be a permanent death.

Reconfiguring equipment may require internal adjustment, soldering, and new parts and will require new fuses of a different current rating to suit the higher line voltage. Fitting new fuses must not be forgotten, equipment may fail if higher current fuses from a 100V set are left in place and fault develops once equipment has been converted to run on 240V. The higher voltage needs correspondingly lower current fuses due to the greater energy carried by the higher line voltage.

I’ve had a recent influx of 100V equipment that has failed because people have a basic stepdown setup and have forgotten that equipment needs to be plugged into it. For this reason, it is imperative to get equipment reconfigured where it can be and to make sure your 100V zone is clearly marked and a fairly permanent arrangement where equipment cannot be moved or plugged in elsewhere. Remember, it’s better for amplifiers etc to be converted to 240V if they can be.

PS

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