I got a pretty decent Denon stereo amp in Japan and brought it back to the States. Juice in Japan is 100 V, just 10 V lower than here.
I was using it with a pseudo surge strip connected to a step-down transformer. In the past I’d had trouble connecting a rice cooker to the transformer–just wouldn’t work at all. But when I plugged the cooker directly into the wall, it seemed to work fine.
Today I noticed that the amp was making a not-good noise, and it reminded me of the noise the rice cooker had made. I tried connecting the amp directly to the transformer–and, like the rice cooker, it didn’t work at all.
So, to recapitulate:
A. The amp doesn’t work when connected to a transformer ostensibly designed to help out in such matters.
B. The amp does work when connected to a multi-plug strip that is then plugged into the transformer; and it works when directly plugged into the wall.
Questions:
Why wouldn’t the amp work when plugged into the transformer? Since the rice cooker wouldn’t work either, what good are these things?
Why did the amp work when plugged into the mult-plug strip plugged into the transformer? Also, what was that weird buzzing sound it was making?
Am I going to destroy my amp and my turntable (same deal, although I didn’t experiment with it) by plugging them into a 110 V socket?
If the answer to #3 is “yes,” and if I can’t use the machines with the transformer, then what should I do?
FWIW, the rule of thumb I’ve always seen and used is that so long as you’re within 10% of the voltage level for resistive or inductive loads (motors, moving parts, heating coils), they’ll function–although some you’ll note don’t work as well.
But when it comes to electronics, it’s best to keep as close to the intended supply voltage as possible.
What kind of transformer are you using? It may be stepping down the voltage too much . . .
Most likely, it would work because you’re close to the voltage, but maybe not close enough to fully juice up the amplifiers themselves. Also, IIRC, Canada & the US are on 60 Hz, and Japan (and the rest of the world for that matter) is on 50 Hz. The difference in cycles may be inducing a ripple voltage in the amps, which ought to be what you are hearing.
By the voltage and frequency, I would think you may do some damage over time, but I don’t think the occasional use would hurt them that much.
You would probably need to find a frequency converter. The voltage, I wouldn’t worry about just yet. But FCs are kinda spendy.
Hopefully, someone with a little more experience in electonics can pop in here to verify. Most of my pithy experience is running power from the generating station to the outlet in your wall.
Tripler
But all of the above is what I remember from school. And those were happy, good times.
I’d make a bet that the transformer is not rated for large amounts of power… rice cookers (and other things with a heating element) draw a lot of current. I don’t know about amps, I suppose they would.
Also, the electronics in something with a heating element would probably be resistant to the voltage change… not too delicate, things like that. I’d be worried about the amp and turntable… especially if they have chips in them.
I got a 110 to 100 transformer for a Japanese Dreamcast in the long, long ago… it’s always been fine.
BTW, when I stick my face up in the vents on the top of the amp, it still feels warm, and the thing has been off for about two hours now. The plug connected to the strip also seemed hot.
In theory, though, it was running on 100 V juice the whole time, so I don’t think I could have been doing anything to overheat it. Unless…
Could the combo of transformer + multi-plug strip have caused the whole thing to overheat? The weird noise stopped when I plugged the amp directly into the wall.
Too bad you live so far from me. I’d love to get my paws on this “transformer” and see what the deal with it is. I remember the thread about the rice cooker (at least I think that was you), and it had me stumped then. I still think it’s not a transformer, per se, as I explained in the other thread because a simple transformer ought to work, unless it’s VERY poorly engineered.
Well a 1500W transformer sounds like it should work, but it could depend upon what you are calling a transformer.
A 1.5KW tx is going to be quite a hefty lump, it will weigh in at up to 20lbs, and possibly double that if it is encased in certain materials such as silica sand plus damage resistant casing.
Is this what you are describing ?
TXs like this are not generally too bothered about the type of load connected to them, most are designed to be self regulating, in other words they cannot deliver enough current to become dangerously hot, what happens is that above a certain demand, the output voltage falls off fairly rapidly, and they usually have thermal cut-outs for worst case scenarios.
The idea that a transformer has some form of connection adjustment for differant supply frequencies is misleading, as this can only be an adjustment of the output voltage based upon the actual amount of the transformer windings that are used.
It actually cannot do anything to compensate for the change in frequency itself, and frequency has effects well beyond just the output voltage.
I think if you describe the transforming device, by weight and dimensions (TXs are usually of certain weights and sizes for certain power outputs) it might be helpful, and if there is some form of information plate upon it this will pretty much help us nail it down completely for you.
I would also expect that it would not be too difficult to obtain the correct internal transformer for your amplifier as Denon sells all over the place and will certainly have an agent in your country that can supply it. This would be the best permanent solution.
The idea that a transformer has some form of connection adjustment for differant supply frequencies is misleading, as this can only be an adjustment of the output voltage based upon the actual amount of the transformer windings that are used.
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I think the point is that since Japan uses 50 or 60 Hz supply, the Japanese amp in question should be happy with either.
In the rice cooker thread Aeschines stated that the weird buzzing sound was coming from the “transformer” itself. Is that the case again here, is the sound actually coming from the amp? If from the amp, do you mean through the speakers or from the amp casing itself?
Check the voltage in your house. You may have anywhere from 110v- 122v.
If you’re on the high side of that it may make a difference with your setup.
Also, make sure everything is properly grounded. < That you have a continuous ground throughout the system.
A to the Q about the noise: The transformer itself made the noise when the rice cooker was plugged into it. In contrast, the amp made the noise when plugged into a mult-outlet strip that was in turn plugged into the transformer.
A to Q about transformer size. Nope, not big and weighing 20 lbs. It’s rather small and light.
I’ve used the amp and turntable today plugged into regular juice. The amp is a little warm but does not seem to be overheating, and the cord is perfectly cool (whereas before, when plugged into the multi-unit strip, it was hot–scary! What could have caused that?!)
Things seem basically OK, but I’ll be keeping an eye out for trouble.