Japanese Amp needs 100v but outlets produce 128v

[4D_Coaxial_Cube]

On March 24th I got out my multi meter and got readings from 3 outlets as instructed from ACUPWR a producer of transformers out of Jew Jersey. I landed on a 300watt 124v to 100v transformer that they handcraft at their facility. Unfortunately when it arrived I realized that the draw of the amp is 350 watts and the transformer is only rated to output 300w, so I will have to send it back. I then measured the volts from a couple of outlets and realized that it was no longer reading 123v/124v like it had a week prior. My direct line has its own transformer and a couple of days after ordering the transformer it blew and when it did it sounded like a half stick of dynamite and upon going out to check on it from loss of power and the loud sound, I saw a puff of smoke blowing away from it. I suspect this is where the change in voltage is from because when the electric company technicians came out all that they did was put a long pole up in the air and attach it to something on the transformer and presto my power was back on. The smoke and sound really makes me think they should have done something else that required more labor and money. So, there could be a work around by getting 2 transformers. One that is designed to bring the voltage down from 124V to 115v, in my case it would go down from 128v/129v 119v/118v and then use another to go from 119v/118v to 104v/103. An ACUPWR rep told me that the amp can operate between 95v to 105v. I am going to contact my electric company on Monday and ask them to service the transformer as I have many valuable pieces of gear I do not want destroyed from over voltage. Is there anything I can get that would insure that my home gets the correct voltage? I would be willing to look into other options. What I would love would be a magic box that lets me control the voltage with a little screen indicating the voltage, but I doubt anything like that exists. Since my imaginary magic box idea probably doesnt exist, what else can I do?

 

[Doodski]

The electric companies don't generally guarantee a specific accurate voltage (eg. 120 V AC.) they only guarantee that it is 60 Hz in North America.

 

[Jim Taylor]

You may want to e-mail or call these people. I cannot guarantee that they have the solution to your problem, but it's worth a try.

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

Jim

 

[amirm]

Since my imaginary magic box idea probably doesnt exist, what else can I do?

Don't worry about it. No one designing equipment that is mains powered is assuming fixed input voltage. Wide variation is allowed. Your amplifier runs on lower voltage and on DC so there is plenty of built-in allowance for such changes.

 

[restorer-john]

A ferroresonant transformer could be a good option for you.

In my experience they are excellent at regulating, but noise (physical) can be an issue.

If you are having wildly fluctuating line voltages, you really should look into it. Are you on a remote (end of line) power feed, or on old poles and wires and/or out in the country?

With 100V Japanese gear, particularly amplifiers, and especially ones with any form of incandescent lighting/meters etc, you do not want to be at the upper end of the tolerance (110V or so) as you will start blowing bulbs and potentially venting PSU caps.

 

[wwenze]

I would check if the Japanese model actually has the same innards as the USA model

Sometimes they even have the same innards as the 240V but they slap a 110V label on it... Usually if you see a 400V cap (without voltage doubler) that is a pretty good tell of design for 240VAC.

 

[4D_Coaxial_Cube]

A ferroresonant transformer could be a good option for you.

In my experience they are excellent at regulating, but noise (physical) can be an issue.

If you are having wildly fluctuating line voltages, you really should look into it. Are you on a remote (end of line) power feed, or on old poles and wires and/or out in the country?

With 100V Japanese gear, particularly amplifiers, and especially ones with any form of incandescent lighting/meters etc, you do not want to be at the upper end of the tolerance (110V or so) as you will start blowing bulbs and potentially venting PSU caps.

Yes, I am on a dead end street in a rural area. My direct line goes to a transformer that only my neighbor's house is also attached to. I contacted my electric company cooperative this morning and they are sending technicians sometime today. This is the transformer I considered going with from Acupwr. Does it differ from the ferroresonant transformer type you mentioned?

AJD25-400 Tru-Watts™ 125 Volts to 100 Volts Step Down Transformer - Use 100-Volt Japanese Electrical Devices in USA/Canada

Watch the video above to see for yourself why ACUPWR transformers are the world's safest, most energy efficient, and most reliable! ACUPWR’s Tru-Watts™ AJD25-400 model is a 400-watt step down voltage transformer that converts voltage from 125 volts to 100 volts, thereby allowing appliances and...

acupwr.com

 

[raindance]

The bang and puff of smoke you describe sounds like a high voltage breaker tripping, which would indeed be reset using a long pole.

 

[EERecordist]

In the US, utilities control voltage from about 114V-126V. It is controlled by the substation transformer. The substation transformer has switched secondary taps and they choose the tap to maintain that voltage range to every home and business, from nearest the substation which will have the highest voltage, to the last house on the line with the lowest voltage.

If there are power shortages (brown outs), or the utility is implementing conservation voltage reduction, voltages can go below 114. It would be unusual for voltages to go higher than 126V for any amount of time.

I would send your house power through a double conversion computer UPS or a battery power pack which should deliver a consistent 120V, then optionally through a Tripplite Isobar, and finally to a variable voltage autotransformer. There are many power pack makers, Bluetti, Ecoflow, Jackery, Anker, and more. Just be sure the one you pick has LiFePO4 batteries which are less susceptible to fire. A long warranty and the capability to return the device to the factory/service center for battery replacement us a plus.

Many of those variable auto transformers have a voltmeter. All of those 3 items have many other uses and resale value. A dedicated custom transformer would not.

 

[4D_Coaxial_Cube]

I really derped it this time. The electric company technician came out and got a reading at the mains in on the meter, 121v, We then checked with his' multimeter and we got a reading of 121. The tech mentioned that when the batteries on a multimeter get low they can get thrown off. He stated that even his' multimeter (which was a lot nicer than mine and inspired me to get a better one soon) can get off readings and when the battery is changed it will read truer results. I felt like a derper for not knowing this and getting the dude to come out, though he was probably fine with spending a little driving time and doing light work over coming to a labor intense ticket.

 

[4D_Coaxial_Cube]

In the US, utilities control voltage from about 114V-126V. It is controlled by the substation transformer. The substation transformer has switched secondary taps and they choose the tap to maintain that voltage range to every home and business, from nearest the substation which will have the highest voltage, to the last house on the line with the lowest voltage.

If there are power shortages (brown outs), or the utility is implementing conservation voltage reduction, voltages can go below 114. It would be unusual for voltages to go higher than 126V for any amount of time.

I would send your house power through a double conversion computer UPS or a battery power pack which should deliver a consistent 120V, then optionally through a Tripplite Isobar, and finally to a variable voltage autotransformer. There are many power pack makers, Bluetti, Ecoflow, Jackery, Anker, and more. Just be sure the one you pick has LiFePO4 batteries which are less susceptible to fire. A long warranty and the capability to return the device to the factory/service center for battery replacement us a plus.

Many of those variable auto transformers have a voltmeter. All of those 3 items have many other uses and resale value. A dedicated custom transformer would not.

View attachment 362286

That all may be true, but the transformers made in NJ from ACUPWR are meticulously gone over. Each one is hooked up to a scope and they make sure that each one performs to tight quality control tolerances. The workers are American trade workers and you can see em in the video tour of their facility on their website. The rep that reached out to me was genuinely concerned and stated hes been with the company since 1980. If i end up having a need for any of those other products for other purposes I would definitely consider such and will be looking into them anyway for learning purposes, thanks for the info. I think I am set on the Acupwer product though... this one worker's mullet from the video really won me over.