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I seem to get my posts deleted over on Audiogon when I try to warn audiophiles about the dangers of 110V Chinese equipment running on 120V USA mains... Probably this is because they have paid advertisers/members selling these products. Anyone out there have feelings about this? I wonder how many fires have been started as a result?
I am an experienced tube repair technician and have seen a number of "smoked" power transformers as well as tubes that have experienced early failure due to 7.6V heater voltage instead of 6.3V... In addition, I have seen smoothing caps rated at 450V running at 500V !!! And these are not the rugged 105 degree type!
I recently emailed one of these vendors and was told that their products are designed for 115V even though the specs and the sticker on the unit clearly states 110V (plus I bought something from them a few years back and had major issues with voltages running amok).
I wonder if electronic products that don't pass certain verification tests (such as UL or CE or some such) would actually void a home owners warranty if they were to cause a fire?
Follow Ups:
............ and ask him why his products are not UL or CSA approved, and then prepare for a lecture on why it doesn't matter and how you don't know your arse from a hole in the ground.
Yes, indeed. Mr. Grant is at the epicenter of Chinese gear and tube imports. Fact and fiction merge, in his world.
Hahahahahaha. It amazes me how people can make design changes to products by ignoring the problem...
So here is the maths involved, assuming 6V heaters:
110V supplied 110V transformer gives heater tap of 6.3V.
120V supplied 110V transformer gives heater voltage of 6.87V.
Doesn't seem too bad, but wait: 110V 50Hz transformers are slightly more efficient at 60Hz and this is why you will see even higher heater voltages.
Translate this to HT: 420V DC on 110V supply translates to 458V DC when running on 120V. When you are using 450V capacitors, this is a fire hazard. Period.
Mains at my house is often around 123V. Figure that one out... Heater voltage 7.04V, HT voltage 469.6V. Imagine where the bias point is for those who don't know how to bias their own amps! What about max operating points for the tubes?
Now we have importers saying their amps are specified for 115V +/- 10%. This is generally not true. The target voltage for the transformers is generally 110V NOT 115V. Saying they are for 115V +/- 10% effectively says they can handle a voltage range up to 126.5V WITHOUT DAMAGE.
Try it. Connect your Chinese amp that has a 110V or 115V sticker on the rear to the mains. Measure the heater voltage. Record the results on this forum. That way we'll find out who is going to the trouble of bringing in safe electronics and who is not. Come on. I dare you all.
Please, Our new Eastern Electric DAC is 120V spec'd not 110V.Not all Chinese gear is the same.We know what were doing!
From my own perspective, my power at my house varies considerably, in the summertime with air conditioning running on a hot day will vary from 110v-112v at 6pm,bias your amp then and then check it at midnight when everyone has gone to bed and my outlet will be anywhere between 118v to 122v. You better recheck your bias on your amps that you just set 6 hours earlier because they are running a lot hotter then you would expect.
Buy from a respected name not the cheapest piece of audio equipment you can find searching Ebay is my advice.
my bedroom system uses a pair of 8 watt Wave Eights from ASL. They've been retubed three or four times now, but the amps must have 3,000 hours on them. I think I got my money's worth out of them a couple times over! Yet I have an Opera turn table that was junk when I got it. After a complete mechanical rebuild it sounds OK (motor is still not upto par). Yet I've got another table of a similar design (made in Europe)that makes the Opera sound like a threshing machine. So I agree that it depends on who built it.
gary
Gary
OK, guys, before I get flamed by all the LEGITIMATE manufacturers who produce products for the USA market, I am referring to those who simply import Chinese goods with no mods at all. You know who they are, they sell via the 'gon and ebay and various web sites.
If the device says 110V in the spec or on the rear panel, that is what I am referring to. If it is modified, please ignore my post.
Oh, and by the way - modified does not mean simply re-typing the spec and a new sticker on the back, it means a new mains transformer with the correct windings ratio.
In France we have the same problem,direct import with voltage problem.But if you buy some goods in a shop,it must have the C.E mark on it.So chinese equipment sold in shops have been factory modified to work with european voltage.
Not necessarily. When I was living in England I purchased a couple of Yarland tube amps. They had a CE stamp on them but were setup for 220V instead of 240V... Same problem!
PS: My moniker is slightly off on the above post as I failed to log in... I am raindances, plural.
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