Sqjudge: Yes the ground is center tapped. I had to go back to the wiring diagram to figure that one out, but that is how it's done. |
Abstract7, Could I assume that the secondary winding on the toroid is center tapped and you grounded the center? That would give you the out of phase balanced =&= 55 volts. Some isolation transformers may have a center tap but I am not sure that it is absolutely necessary to ground either leg of the 110 as long as the safety ground is intact. Can anyone in the know comment on this. The main reason for the isolation transformer is that many have a faraday shield between the input and output windings that helps to prevent noise from getting thru. Electrical supply houses can get multi-KVA transformers that can handle 50+ amps.
Audioken, If your new house is actually going to be 440 volt (and you are in the USA) you will need one of those big step-down transformers feeding the distribution box. Let me know how hard it was to get the power company to install 440 service. I will do it for my garage so I can force them to put in a single transformer on the pole just for me! |
Thanks for the input. I appreciate your advice and I can incorporate some of ideas easily enough into my building project. I'll be better able to explain to my electrician what I want and why.
Thanks again. |
Mine cost me about $500 plus I supplied the transformer and EMI/RFI filters. I was having other work done, so it was relatively inexpensive. Also, the distance from my incoming power to the audioroom is only about 25 feet. I don't recall the prices of the transformers, but if you go to the Allied website there are several that should work, depending on your power requirements. |
Assuming that these wires are accessible and not hidden in dry wall, or plaster, approximately how much would say work like this would cost? How much is the equipment?
Thanks.
jd |
The transformer I used was designed to run in this balanced mode. Again, it was designed for medical equipment, so noise and balanced topology are really what is needed. It's also designed way beyond it's rating of 30 amps at 220 volts. I did do a search with Allied electronics and found several toroidal transformers which should work the same way. Keep in mind this balanced design is not really that big of a deal. The 220V circuits are balanced topology with two poles at 110V. All the transformer is doing is stepping down both of those poles to 55V at double the amperage (minus the loss in the torodial coils). |
Glen, you state that you are a professional electrician, yet you also state that you "Then ground to a seperate ground rod independent of your service ground" every time.
You had better hope your local inspector doesn't read this as this is not code and can be dangerous due to different ground potentials. However, I agree with you that there may be some sonic benefit so I am going to be doing it in my system. |
Sean.. with all your knowledge and equipment to the pursuit of audio nirvana why haven,t you switched to fuses.Fuses is a giant leap forward in this.
steve |
Glen, thanks for sharing your info. It's always good to hear from a professional. I would like to share some of my findings in regards to some of your statements though.
As to your comments about #12 being fine for runs up to 150', i would disagree with that. I have seen VERY noticeable voltage drops at well under 30 amps of draw and for less than 8' of an 8 gauge cable. I would assume that a hard draw of 12 - 15 amps using #12 for the length of run that you mentioned would result in both a measurable voltage drop due to series resistance and dielectric losses and distortion of the AC sine wave. I think that those reasons are why some folks have such good luck with items like the PS Audio Power Plant and other "power regenerators". All of the "losses" and "distortions" are kind of "eaten up" by the regenerators and "reincarnated" as "clean power".
While most folks would think that a LONG run of wire like that is next to impossible in a "reasonable" sized house, they don't take into account that the wiring is typically routed rather indirectly and can take some rather strange turns before getting to the final destination.
I hope to bring home one of my scopes sometime soon and do some measurements on one of my systems. I'm strictly talking in terms of the electricity going into the system and how it compares to what is at the breaker box. In the meantime, i'm still assuming that overkill is "better" and that "too much is not enough" in terms of heavy wiring and short runs working best. Sean
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Hi,
I just happen to be an electrician. I just finished wiring a high end audio store with two home theatre showrooms. I also have done some audio trouble shooting for people in their homes. I don't claim to know as much as the last two guys. Some of that stuff is out of my league. Very clean power to say the least. Here's what I put in for a $100,000.00 theatre system. I like using a dedicated hot with a dedicated neutral and a isolated ground at each outlet that demands up to 10 amps. Using a 20 amp circuit with a 20 amp IG recptacle(orange). If your less than 150' from the panel I wouldn't worry about voltage drop #12 wire is fine.
If your more than 200' from your panel or do not have adequte room for more breakers I would add a seperate panel near your theatre 80 amps 240 volts will run a good size system, Make sure to add an isolated ground bar in the panel. Then ground to a seperate ground rod independent of your service ground. That will establish clean ground through your system. Tie all your recptacle grounds to the iso grd system. run dedicated 20 amp circuits to all primary power locations. Sub woofer, mono blocks, plasma screens, projector and at least two to your gear. That may sound like a lot of circuits and a hell of a lot of neutrals. Your electrician might even scratch his head over the isolated ground if he is not well versed in electronic installations. But when installed correctly this configuration works dynamite. I do it this way every time.
With much success. |
Abstract7- Would you say more about the transformer? In particular, how did you get it to produce a balanced output? Was it designed that way, or is there a way to do this with any transformer that can take in 220VAC and put out 110VAC? Do you recommend a particular brand/type of transformer?. Does the transformer provide adequate surge suppression?
Other questions:
What types of filters are you using on your analog and digital lines?
"rupertdacat"
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to get it to produce a balanced output? Was it designed that way, or is there a way to do this with any transformer that can take in 220VAC and put out 110VAC? Do you recommend a particular brand/type of transformer? |
This is what I did in my audio room:
220 Volt 30 Amp from electrical panel to Mud room (adjacent to Audioroom) using 6 AWG stranded copper wire. This is connected to a toroidal transformer which converts 220Volts to 110 Volts at 60 Amps. Both poles are live +55 volts and –55 volts (out of phase). This goes to a sub panel with four separate circuits. The circuits are dedicated and have independent EMI/RFI filtration. This is an industrial product which I got from a company I previously worked for. It was used in medical devices to insure low EMI/RFI. Each of these circuits is run to true ground independently. Then I used 10 AWG stranded copper to the outlets. The circuits are dedicated, one is for the amplifiers, one is for the projection TV, one is for digital source components (all of which have additional independent EMI/RFI filtration), one is for analog source components. Independent grounds are used for each circuit. There have been cautions against this, due to the possibility of having slightly different potentials with 2 grounds. So although this worked well for me, I don't necessarily recommend it. The part that is really critical is the toroidal transformer with two live poles out of phase. I think this made the largest difference in terms of lowering the noise floor. Sean has some good suggestions, which I may add to my system, such as the Pass & Seamor outlets. I'm currently using Hubble hospital grade. |
Depending on how serious you want to get, you might want to have a 20 amp line for each amplifier and two seperate 15 or 20 amp lines for the rest of the gear. It has been recommended that digital gear ( such as CD player / transport / DAC, DVD, tuner, etc..) be placed on its' own line rather than share with other analogue components like your preamp, TT, etc... This should give you plenty of outlets and current to play with.
One thing to think about is outlet placement. If your running monoblocks or ever intend to go that route, keep in mind that you'll need outlets away from the rest of the gear. You might also want to have outlets running up the wall in a vertical array where you'll have your rack set up. This can make your installation MUCH neater due to the lack of excess power cords dangling all over. Something else to keep in mind is that you want all of these various circuits tied to the same grounding point.
In terms of wiring, i would suggest 10 gauge throughout to help minimize voltage drop. Others have suggested the use of an external breaker / fuse box outside of the rest of the house wiring i.e. a seperate box "jumped" off of the mains. I know that Bob Bundus has played with breakers vs fuses, so i'll let him share his experience in that area.
From what i've gathered, there are some Pass & Seymour outlets that seem to offer the most bang for the buck. You can find more specific info such as part number over in the Cable Asylum. Large contact areas with good tension in terms of holding the plugs in.
Keep in mind that it easier to go "crazy" now than to do it later once the walls, etc... are all installed. Good luck and hope your new house is everything that you hope it will be and more. Sean
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