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Using a 100 Volt amp on our 120 volt power line ?

There is a gentleman selling a high end Onkyo integrated amp on another site, which is a Japanese model, to be operated at 100 volts. He has been using it here in the states for 6 months ( without a step down transformer ), claiming no problems exist, and that it sounds wonderful. He does say in the ad that although he has had success with a few Japanese, 100 volt units, powered by our 120 voltage, he recommends the buyer to use a step down transformer ( he explained, to protect himself if a problem arose ). I guess my question is : Can this work without causing a problem to the amplifier, or cause a fire ? Enjoy ! MrD.
mrdecibel
amg56's avatar
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amg56
887 posts
 

MrD

Although I don't live in the US, other posts (in more to discover) recommend a change to 120v buy a technician (Accuphase was mentioned) but I am not sure was or where they are in the US.

phomchick's avatar
phomchick
209 posts
 
Bad idea. You would definitely need a step down transformer. Running it at 120 volts could be seriously shortening component life. 
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amg56
887 posts
 

@phomchickI I'll defer to your advice on that. Cheers. A

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phomchick
209 posts
 
Think of it this way: would you be comfortable running a USA amp at 144 volts? If it’s possible to modify, the power supply, that would work as well as a step down device.
jea48
4,266 posts
 
He has been using it here in the states for 6 months ( without a step down transformer ), claiming no problems exist, and that it sounds wonderful.

If the guys mains voltage is 120Vac he has been overfeeding the amp by 20%. Usually the max continuous over voltage is 10% of the rated nameplate of the equipment. (Check what the nameplate voltage rating on the amp actually says. Is it 100Vac only? 100Vac X 10% = 110Vac.)

Note even though the mains AC voltage may measure 120Vac at any given time of the day that does not mean there are not times when the mains AC voltage does not peak higher. The owner of the amp already has been operating the amp beyond the manufacturer’s built in 10% fudge factor.

For 6 months he has been running the amp off of ???Vac, 120Vac nominal, voltage. It is possible components in the amp have already been stressed.

As for reducing your mains voltage to 100Vac you can buy a converter. Usually they are autotransformers.

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