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Mats_J

OT: 220V eqpmt on 115V

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Hello gurus,I have an intricate question for ya. I have an Altec Lansing ADA885 surround system. The problem is that it was bought in Europe meaning it is marked for 220V/50Hz voltage. As I have moved to Canada I can only get 115V/60Hz power supply.I took apart the amplifier/subwoofer unit and the inlet circuit is connected to a toroid core transformer with three secondary coils. Parallell with the primary is a varistor connected. I guess for shunting voltage surges and blowing the fuse which is connected between the power supply and the varistor/transformer. My guess is +5V and +-12V on the secondary sides. No type markings on the transformer unfortunately. Would it work to exchange the transformer with a new one with a primary coil for 115V? I know I could buy a voltage converter but it would probably be as expensive as buying a new surround system.Any thoughts appreciated!

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Mats,Does the toroidal transformer have dual input windings? Some equipment is designed to be switched between 115 and 220 by using such a transformer. With the input windings is series, it operated on a 220 power source. When the windings are paralleled, it operates on 115.If the transformer does not have dual primary windings, a transformer replacement is a possibility. However, I would be surprised of the secondaries are 5 and 12 volts. This seems too low for audio power circuitry.Mikewww.mikesflightdeck.com

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Mike,Thanks for your prompt reply. I didn't check the transformer thoroughly, I will do that tomorrow and see if there's a possibility to switch the inpout windings. I will also measure the secondary windings. It should be possible to calculate backwards what the secondary windings are supposed to give at 230 right? I'll be back, ;-)

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Hi Mats,You are correct. The ratio of the output winding AC voltage to the input winding AC voltage will give you the transformer turns ratio. Using that you can determine the intended AC output voltages.Mikewww.mikesflightdeckbooks.com

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Ok, an update on the transformer.The output voltages I get are consistant to the lower input voltage and the original ratios. I also managed to find a label on the transformer.I've attached three pictures of the physical layout of the coil and the label plus a drawing of how I think the coil is designed.I've tried to do some research of any company selling an animal like this but came up with virtually nothing. Anyone have a clue of where I could get a similar coil but with the primary winding for 115Vac. Preferably in CAN, or north US area?http://forums.avsim.net/user_files/94915.jpghttp://forums.avsim.net/user_files/94913.jpghttp://forums.avsim.net/user_files/94914.jpgCheers,

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Mats,After poking around at transformer manufacturer sites for a bit, I think what you have is a custom transformer designed specifically for that piece of equipment. I was unable to find standard units with similar output winding configurations. [ www.nuvotem.com www.toroid.com http://avellindberg.com ] Some possibilities...If the manufacturer of your particular equipment markets a US or Canadian version of the equipment, you may be able to buy a replacement transformer from them.You could use two or three transformers mounted externally to your equipment, and run the three low voltage AC secondary voltages into your equipment, bypassing the European transformer.If you're really hardcore, rewind the existing transformer. Remove the existing windings, counting turns as you take them off. Replace the primary with two windings each with half the turns. Connect the windings in parallel for use in Canada. Series them if used in Europe.Mikewww.mikesflightdeck.com

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Playing with 220 or 110 volts scares me enough to not think about these kinds of things - and I bet the insurance company is not fond of the idea either :)Anyway, couldnt you get a voltage transformer from your local equivalent of radio shack? Would those work, or would the transformer create a strong humming noise?//Tuomas

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LOL...Tuomas. I can understand your concern. As long as you protect your circuits for damaging currents, it should not be a hazard though. And we're only talking about a transformer here. :-) Having a swedish finite license for electricians I feel I have at least the theoretical knowledge for this kind of operation. ;-)"What the insurance company doesn't know, they won't worry about."I am looking into a so called step-up transformer as you are suggesting. I can get a reasonably cheap one, capable of supplying 500W (Not a word about the VAr though) for less than US$30. This is basically just adding another transformer and protection to my already existing transformer and protection. So would be neat to combine those two. I'm looking into replacing the one I have with 3 new ones, preferably toroids as the are smaller and have less hum and stray magnetic fields than laminated EI ones.Cheers,

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Thanks for your invaluable input Mike,> If you're really hardcore, rewind the existing transformer. Remove the > existing windings, counting turns as you take them off. Replace the > primary with two windings each with half the turns. Connect the > windings in parallel for use in Canada. Series them if used in Europe.Yeah right. :-) You'd love to see me doing that, I bet! I may consider myself hardcore. But I'm not that hardcore. :(Looking into replacing the one with three new toroidal ones from Hammond. Should fit into the original casing. Thanks again,

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>LOL...>>Tuomas. I can understand your concern. As long as you protect>your circuits for damaging currents, it should not be a hazard>though. And we're only talking about a transformer here. :-)>Having a swedish finite license for electricians I feel I have>at least the theoretical knowledge for this kind of operation.Well that sure does help :-)I just tend to be careful, you know we have readers from countries where they dry cats in microwave ovens etc (hopefully they have a good sense of humour though), so you never know.. ;-)>"What the insurance company doesn't know, they won't worry>about."Insurance companies can use google too. :)>I am looking into a so called step-up transformer as you are>suggesting. I can get a reasonably cheap one, capable of>supplying 500W (Not a word about the VAr though) for less than>US$30. This is basically just adding another transformer and>protection to my already existing transformer and protection.>So would be neat to combine those two. I'm looking into>replacing the one I have with 3 new ones, preferably toroids>as the are smaller and have less hum and stray magnetic fields>than laminated EI ones.Yea, I got one reverse - we have a dog clipper that runs on 110V and it works fine with a 220->110V transformer. The active current frequency might be different too thouhg - I remember that some people who got LP-record players years back from the US and converted them to 220V didnt realize the turntable motor was synced to that.. :) Or maybe it was an urban legend..//Tuomas

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