110v down to 100v power converter, is it stupid?

I have several amps and cd players made for the Japanese market that I bought here in China over the years. They are 100 volts. Is it sensible or silly for me to have a power converter made to bring the power down to 100 volts when I use them in the US? I believe I read that the US is around 115-120 now anyway. I don't want to risk damaging my cd players. Silly or not?

 

Not silly at all!!!

Power is proportional to voltage squared. 120^2/100^2 = 1.44

That means your Japanese appliance *might* be subjected to 44% more power than it is designed for. I recall seeing signs on mini hair dryers in the Akihabara warning not to connect directly to U.S. electricity.

But many electronics use power supplies that can compensate-read the plaques affixed to your equipment to see if they say anything like "100-220V"

 

No they don't. Just 100V.

 

I agree, if the equipment is prepare for only 100 v the transformer will be a necessity and in terms of reliability (or "life" of the apparatus) as a general rule is better to have under-voltage than over-voltage.

 

Only by examining the circuit can we tell if a stepdown transformer or autoformer is needed.

In general, if the unit uses a conventional power transformer it is designed to work at a particular voltage. It seems to be common practice among Japanese manufacturers to make one version for JDM (Japanese Domestic Market) and another for many or all export markets.

If it uses a switchmode power supply it is designed to work over a range or two ranges of supply voltage.

If it has a transformer it may have multiple taps or windings for multiple voltages and it can often be set up for what you have.

 

Guys, none of these devices have switchmode power supplies.

I am more worried about my cd players rather than the amps. Anyway, it won't cost me much to have someone make a step down transformer/converter.

 

They are easy to make from junked Sears Schumacher car battery chargers which have a 120:16 volt transformer. Wire it as an autoformer.

You can buy ready to go ones on eBay as well.

 

Definitely a good idea, as the Japan electronics industry did not want exported items (cheaper then) to be reimported into Japan. So they are designed for 100V not 110V.

There were even laws against officially selling non 100V only stuff locally in Japan, unless marked for tourist sale for export.

I have two nearly indentical Matsushita Electric made appliances that are rechargeable on an inductive base like an electric toothbrush. One is US market and one Japan, Other than one says "National" and has some Japanese where the other says "Panasonic" and English markings, the only difference is the charge base on the National one is 100V only, which I didn't know or thought it would matter. The Panasonic one is 110V and US market.

Both chargers put out the same to the device and can be interchanged. The 100V charger got warm when used and eventually turned brown on the plastic. The 110V works fine - no heat, no yellowing.

What I have seen is that A/V equipment is similar and intentional.

 

On a device like a toothbrush a simple resistor for dropping would probably work pretty well.

The Japanese high end domestic market stuff is 100V only on its power transformer primaries, I didn't know there was a law requiring that.
But much of the seventies and eighties stuff had strappable multi voltage windings. They were hard jumpered and with a little moxie you could figure out how to rejumper them.

 

Buy a single device that can handle all you're equipment, you can probably put in near your breaker box and run a dedicated line for it. A Variac would work, its an off the shelf item.

 

No, do not use a Variac.

A Variac is inherently inefficient and leaving it at a constant setting for a long period of time will ruin the brush and eventually pit the windings.

 

I have a 47 Laboratory amp that was purchased in Japan which operates on 100V.
I contacted 47 Labs and asked the same question regarding use here in North America.

They said there is no harm plugging into 115V...it will just sound different.

I ended up purchasing a step down transformer since they are cheap. To be honest, I heard little to no difference in sound quality and no harm came to my gear when operated at 115V.

 

Definitely a good idea, not only for the disk players, but tube amps will thank you for it with reliable service.

 

I have actually bought Japanese gear in the 1980s and 1990s and run it on a Variac, and never had a problem. The Variac still works today, though I rarely use it now.

 

I'd like to see a picture of that. I think their stuff looks cool.

 

Connect it directly and don't worry. 10-15% overvoltage is nothing. Electronic equipment is designed to take it. Japan has a low voltage for higher safety.

 

I was in a similar position and got someone to build me a bucking transformer - this has worked out very well and is an efficient solution.

 

How did you get the stuff? You bought it there personally or had help?

 

Bought it there myself in Akihabara.

 

Holy crap, there's another Burt here!?

 

IIRC, Japanese voltage is not only a different voltage, it is also a different frequency.

Haha. I just double checked my facts, and the answer is crazy. The East of Japan uses 50Hz, and the West uses 60Hz.

I always thought it was 50Hz. See if your gear specifies a particular frequency, but some of the pages I've read say that most Japanese equipment is built to run on either.

What I have also read is that in general, it is OK to use a higher frequency than specified by a component, but using a lower frequency will cause heavy stress on a power supply.

My solution for powering my Pioneer X-9 laserdisc player has been to use an old PS Audio P300. On these AC regenerators, you can select the output voltage AND the frequency, so I have only ever fed the LD player clean 100V, 50Hz, complete with surge and overvoltage protection. It's a good solution. And I think these are pretty cheap on the used maket.

ccm

 

Any JDM Japanese equipment is designed for either 50 or 60 Hz. Export equipment is designed for either as well, in general as long as there are multiple taps or windings on the transformer.

Power transformers work over a range of frequencies, and they tend to work better (in terms of running cooler and quieter) over higher rather than lower ones up to a certain point. Generally any small electronic transformer designed for 50 Hz likes 60 better, and so forth.

Where frequency must be specific is when you have motors involved. AC motors turn at a speed controlled by frequency.

 

Lower voltage is not safer. Once you are over the breakdown curve of human skin, it's strictly a matter of current availability and from any AC socket there is way more than is fatal under the right conditions. Japan is just being, well, Japanese in picking a voltage not used any where else, and in having two completely isolated electrical networks at different frequencies. They also have two different rail systems on different gauge trackage.

 

Yes, to use higher frequency is safe.

Of course lower voltage is safer. The current kills, and it depends on our body resistance and voltage. I don't know about "right conditions", but under the same conditions your chances are better with lower voltage. Japanese selected lowest reasonably possible voltage, but they pay the price having to use bigger power cables. Many more people die from electricity in contries with residential voltage 220V. 100-110 usually don't kill us, but I will take 100 over 110 any day if I would have to be hit.

 

I was taught in school that the Europeans regarded 220 as safer because it was more likely to fault and blow a fuse than "sit there and cook somebody", as in the classic scenario of people who would put a radio on the bathtub and it would fall in and continue to pass lethal, but non-fuse-blowing current.

Ham radio operators who are electrocuted are almost always killed by 120V and not by the kilovolt B+ supplies their transmitting amplifiers use: there is an eighty year database on this.

I think you have to get below about 50 volts peak (on AC) before you get into a real difference in the ability of a power supply to cause lethal or debilitating shock.