|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
71.131.185.21
In Reply to: How to Spec a Dedicated AC Line. posted by Omera_T on April 1, 2007 at 21:16:06:
I've not used it, but would go with it for dedicated circuits if I were to install them today.DO NOT install separate ground rods. A nearby lightning strike would cause tremendous lateral currents to flow through the earth. The voltage difference between your main house ground and the dedicated circuit grounds could easily exceed the flash-over voltages of your fixtures. Your audio components would have their AC neutral inputs at one potential, and the AC ground at several thousand volts difference. Your equipment would be destroyed, your house in danger of catching fire, and any nearby people in danger of being killed.
I suggest a separate circuit for each component, as the added cost is low once you pay to have the electrician arrive. Run each circuit straight from the main circuit breaker panel, on a single leg opposite the leg that supports noisy non-audio appliances. Have some distance between the cables to reduce coupling. Run each circuit into a separate single-gang plastic box. Again, this is to mimize coupling of noise between the circuits. Using a sub-panel causes all the circuits to share the common heavy feed wire, and reduces the benefit of dedicated circuits.
Install Oyaide Ultimo outlets and carbon-fiber cover plates. Clean the bare copper wires thoroughly before they are inserted into the outlets.
Follow Ups:
Al,Thanks again for chiming in, and for the thourough directions you have given.
Two questions though. Is there a way to reduce the ground noise without a seperate grounding rod?
And, Back to the original scenario, what if there was an audio grounding rod in close proximity to the main grounding rod, just few inches away. Any safer?
You can have a second ground rod bonded to the original and still meet code (better to find an electrician who understands the details of what this requires: I'm an electrical engineer but not a licensed electrician).The trouble with the USA power grounding scheme is that the earth connection is there for lightning protection, not to sink electrical noise. The code requires all circuits to have their neutral and safety-earth wires connected to it. This means any higher-frequency noise generated anywhere in your house goes everywhere on the 'ground' wiring. The fact that there is an earth connection electrode and heavy wire to it does not reduce the ability of higher-frequency noise to move around. The earth connection reduces lower-frequency noise in certain limited circumstances, but not enough of the noise that degrades audio system performance.
My approach has been to add filters at the non-audio noise sources, add damping networks where necessary, and treat my audio system cables to reduce their ability to resonate. I have four dedicated circuits, use a separate circuit for each one of my components, and I still find benefits from improving the filtering of non-audio noise sources and damping the house wiring with R-C networks.
Non-audio noise sources are things like computers, UPS devices that feed computers, appliances with computers inside (such as microwave ovens and high-efficiency furnaces), video gear, anything with a small external power supply, and anything with a fluorescent display. My worst noise sources are a digital video recorder and a combination microwave/convection oven with a complicated control panel.
Filters can be simple surge-protector power strips with RFI/EMI filters built-in. However, these couple some line-neutral noise to the AC ground wiring, even if the appliances plugged in to them use only two-prong plugs. A further step is to insert anti-parallel rectifier diodes in the ground wire to such filters. These diodes have very high impedance to small noise voltages, but will allow fault current to flow to maintain protection. They keep most of the coupled noise out of the house's AC ground wiring.
Damping networks are R-C filters similar to the QuietLines devices. They reduce the electrical ringing that takes place on the house wiring.
Damping audio cables is a more esoteric topic. I've discussed it from time to time on the Cable Asylum and in Tweaks.
One other thought.Since my system is in a detached garage (second floor guys pad/office, a la' Fonzy), I'm thinking that the panel in the garage is a sub panel off the main panel in the house. So, I'm probably being tied in to not just the "noise makers" in my garage office (including a fish aquarium with continuous pump and flouescent lights, currently on same ciruit as my audio), but all the ones in my house too. That's a lot to filter, with four kids and myriad electronics.
Would it make sense for me to look at either: a new electrical service run straight to the garage ofice from the utility pole. Or even a dedicated panel just for my audio, again, straight from the utility pole. I could dedicate the Diamond HandiWire, Oyaide etc from there. I guess that means two electric bills, and don't know about start up costs.
Or, a power regenerator for the audio, like the new Premier from PS audio that I read about. Thanks in advance for any input.
Yes, you may be on a sub-panel and subject to all the noise from the main house as well as whatever else is powered by the sub-panel.If you had the utility company install a separate drop for the garage or even your audio system, it would have its own earth rod and would markedly improve your ground isolation. This might be cheaper than a house full of fancy filters.
Regenerators have limited current capacity, so might restrict dynamics with some combinations of amps and speakers. Running the power amps straight from the AC admits all the AC noise to your system. You still have the problem of power cord resonance between the regenerator and the equipment.
My filters are DIY and still under development. Filtering for noise sources is a slightly different problem from filtering the AC into audio components, but a good tweak is to use antiparallel rectifier diodes in the AC safety-earth lead in either case. These are at least 6-ampere capacity and the higher the reverse voltage rating, the better. Some inductance in series with the diodes is good: JW Miller 5522 RF chokes are made of beefy wire and kill a lot of the noise that gets through the diode capacitances. A 1K shunt resistor might be needed for things like UPS devices that sense ground and shut themselves down if they don't find it.
Al,Thanks for being so generous with your time and expertise. (BTW, I have emailed Alan Kafton to place the order for th Cryo'd Diamond Handiwire and Oyaide outlets per your recco. He responded promptly.) I may hold off onthe Oyaide carbon fiber covers as they are pretty pricey, to but three. Maybe later.
Your post makes sense to me. Could I trouble you a specific brand of the noise source filter you use or would reccomend, maybe Alan could provide me some of those at the same time as the other stuff.
Thank you much,
-Tim
Wow!Thanks for steering me clear of that! I had discussed it (seperate grounds) with an electrician ealier and I think he would have done it. Scary. The guys wants to follow orders I think.
Appreciate the other good input too.
Thanks for the mention, Al. I recently double-cryo'd some 10-gauge Handiwire for a customer, and was lucky to find it. It seems that Ace is now converting over to the dreaded Romex brand, just like Home Despot did last year. I am now looking for another supplier....drat. If I have to go out-of-state, it will likely be more costly, but definitely worth it for the sonic benefit.
> > It seems that Ace is now converting over to the dreaded Romex brand < <That's because everyone comes into Ace and asks for "Romex" because they don't understand that it's a brand. They think it's a type of wire.
....than industry branding, although your suggestion is not without merit. Many times a particular manufacturer or distributor will aggressively pursue a marketing plan, offering substantial financial incentives for doing business. For big box and national retailers, the math is easy.
This post is made possible by the generous support of people like you and our sponsors: