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I wired my house for sound throughout. Each room has four speakers, 2 channels, and home runs to a sound closet. I have a Cress 70.7-volt stereo amp and 34 Sony 3-ohm cube speakers. I believe I need to find some step-down transformers but everything is geared for 2-4-8-16 ohm. Any idears? I am new to this so much of the info is Greek to me right now. Thanks.
 

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First thing you need to find is the right subforum, but I'm sure the moderator staff will relocate this thread soon enough.

Now, onto your problem. Why are you using a 70V amp for home audio? High impedance amps are for commercial paging applications...
 

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Thanks for the reply. I wanted to be able to run sound throughout the house but, in many rooms, I might turn the speakers off or switch to an in-room source (TV, radio, or CD). That means that the main amp might see 4 speakers or as many as 34. That seems to require a system like in a commercial building, huh? So several years ago I found on eBay a bunch of Sony cube speakers cheap. Sweet! I bought 34 and now all of the speakers in the house will match. I thought thet, while I'm waiting to finish the house, I would use one of these on an old tuner/amp in the garage. Burned out the amp. Huh! Turns out the speakers are all 3 ohm. So, THATS why they were cheap! Then I started talking with a friend who does commercial systems for churches. He said that what I need is a constant-voltage system but it needs to be a stereo unit or two mono amps. Most are mono. I found one on eBay that was stereo. Score! Now I need a step-down transformer for each of these speakers but they're all 3-ohm. None of the step-downs have leads for 3 ohms. That's where I sit now. I think the speakers are 80 watts.
 

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Commercial PA systems have been 70v forever and, back in the day, Radio Shack (pre-Source days) used to sell what you're looking for. It's an odd way to do home surround sound and not sure what it will sound like.

Most commercial speaker lines include the 70v transformers with the speakers. Much harder to find as a stand-alone item. You'll be hard pressed to find one for 3 ohm, but a 4 ohm might be close enough. OWI still makes them. Not sure if anyone in Canada sells them, but B & H PhotoVideo do and they ship to Canada using Borderfree.

Hammond also make a 70v transformer, which you might be able to hunt down locally. I would also check musical instrument stores like Long & McQuade.
 

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Thanks loads. I'll check it out. This is all new to me so the terminology is a bit strange. I'll try a 4-ohm transformer. I thought it might be as simple as stepping down the voltage by 6 or so and selecting an appropriate transformer since all of the speakers are the same. I don't know what voltage range normal speakers use.
 

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FWIW, are these three ohm speakers any good, or are they cheapies from home-theater-in-a-box systems? Did you buy them from some retailer that was stripping them out of kits just to harvest the good parts? My worry is that you will spend more than the speakers are worth just to get a half-assed system.

This is not a normal approach to residential audio!
 

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Yes, I'm getting that impression about the speakers as I get into this. I wouldn't know how to determine that the speakers are low, medium, or high quality. Now about the normal approach to home sound... what would that be? I remember that I asked that many times at sound retailers when we were building the house and never could get a real consistent answer so I wonder if this is one of those instances where there are about 1017 ways to do it? Thanks.
 

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For the whole-house audio controller and amp, here's what I'm picking up in a UPS store across the border. I hope I can pick these up tomorrow and install during the weekend.:)

HTD: http://www.htd.com/Products/Lync

I have a combo of Eaton speakers installed by builder and two pairs of Emotiva speakers.

There's a whole new world of home automation including distributed audio. I'd echo the concern of the others that you may not want to spend more money just to try and keep your speakers which may not be the best solution for you.

Good luck and keep us posted.
 

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I have a Cress 70.7-volt stereo amp and 34 Sony 3-ohm cube speakers. I believe I need to find some step-down transformers but everything is geared for 2-4-8-16 ohm. Any idears?
Speaker impedance is nominal, not exact, so either the 2 or 4 ohm tap should work fine. I would try the 2 ohm tap on a couple of speakers first. If the volume is too low, try the 4 ohm tap. A lot depends on the quality of the amp. Some can tolerate low impedance better than others. A 70v system is the right way to approach this. Connecting 34 speakers to a standard amp without some sort of impedance matching will burn it out quickly.
 

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Discussion Starter #10
Good deal, Scary. I think it will be worth it to pick up some transformers and try it out, then. Even if they are cheap, I can get sound through the house and upgrade the rooms later as I want. Most of them will probably be fine with a lower-grade speaker and it won't cost me a fortune. Thanks a lot everyone for all of your help on this, We rookies need all the help we can get. My dad was an expert but he's gone now and left a rookie son to the world. Sorry 'bout that, guys! Hey, you all have a very merry Christmas!!!
 
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