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In Reply to: RE: Incoming AC legs NOT created equal... posted by tweakmenow on May 29, 2017 at 19:42:53
I'm sure there are many things that could be putting noise on your electrical system. The 'fridge, sum pump, florescent lights, dimmer switches, AV systems, the radio tower down the road to name a few.
I prefer to use my oscilloscope to measure noise on my audio equipment and/or electrical system. I have the advantage of my own repair / restoration bench so equipment is available.
Something as simple as Pixelphoto's device will be a good start to curtail line noise. I have found a couple Belden and Tripp Lite surge protectors to work well.
Follow Ups:
An oscilloscope can be handy for noise detection, but a spectrum analyzer is even more so as it will not only show that there is noise, but what frequency, amplitude, etc.
I used the Audio Prism version of the Entech box many years ago to find out that it was my Adcom GFA555II that was dumping a boatload of noise back into my AC line...I ran that amp through a Corcom 20A filter in a box after that and it sure depleted the amp's noise pollution.
As always, YMMV
An oscilloscope can be handy for noise detection, but a spectrum analyzer is even more so as it will not only show that there is noise, but what frequency, amplitude, etc.
I used the Audio Prism version of the Entech box many years ago to find out that it was my Adcom GFA555II that was dumping a boatload of noise back into my AC line...I ran that amp through a Corcom 20A filter in a box after that and it sure depleted the amp's noise pollution.
Rick,
What do you think you would have found if the Adcom GFA555II was on a different circuit than the other audio equipment of your audio system? Would you have seen the noise at the receptacle/branch circuits of the other audio equipment? My guess is maybe but to a much lesser lower degree.
I believe that is the main reasoning behind installing multiple dedicated branch circuits to feed an audio system. To decouple the power supplies of the equipment from being directly coupled from one another if fed from only one branch circuit.
Aftermarket power cords can help do the same thing sometimes, to some degree, if the power cord doesn't get in the way of the SQ of the piece of equipment the power cord is used on.
Your thoughts?
It would have still polluted the line as all lines lead back to the fuse/breaker box, it would have just had farther to go...if it would have been on the opposite phase, maybe not as much, but crossing phases like that is a no no.
When the Audio Prism device was brought out to the market, I took and did a lot of experimenting with it on differnt noise conditioners, power cords, etc., and it was interesting to see what did what....this experimentation was over a decade ago, so I didn't have any of the currently available line conditioners at my disposal....
It was interesting to take the power conditioners that quietened the line noise the most and then to plug an Icom R-71A SW receiver into them with a short telescopic whip antenna and attempt to receive WWV, WWV is a broadcast from the National Bureau of Standards in Ft. Collins, Colorado providing time interval information on 2.5, 5.0, 10.0, 15.0, and 20.0 MHz 24 hours a day. This experiment was carried out during the day when 15.0MHz was the strongest signal into South Texas, and the house I was doing this in had exterior walls of stucco, cement over wire mesh, so it was basically a Faraday cage.
When trying to receive a signal without any power conditioning, the noise level in the receiver was nearly at signal level...but, when a combination of power conditioning and power cords was tried that had shown good results with the Audio Prism device, the noise level fell greatly and the signal appeared cleaner, clearer, and easily readable. The Icom receiver is a very high quality unit built to a standard that made it one of the top rated SW receivers for many years. Yet, even this device with its' ostensibly well built internal power supply was affected by the AC feeding it.
So, what does this have to do with audio?
It showed me that noise pollution from our AC lines can get in through even well designed and well filtered power supplies and affect what we hear from our systems...we may not notice it overtly, but can tell when it's influence is gone.
I just supervised an installation of four home runs, dedicated lines, in a client's listening room each run made with 10ga, wire and outfitted with Shunyata AC outlets, and all run from the same phase...I have not had time, though, to really evaluate the system as he has some guests temporarily staying at the house, but a Shunyata Denali for the source equipment did perform much better than an MPC 12, even with the dedicated lines....
Two of the other lines each have a Pass XA250.5 on them....I don't think we are going to be current starved now!
And, as always, YMMV
I just supervised an installation of four home runs, dedicated lines, in a client's listening room each run made with 10ga, wire and outfitted with Shunyata AC outlets, and all run from the same phase...I have not had time, though, to really evaluate the system as he has some guests temporarily staying at the house,
Rick,
A few questions if you don't mind.
10ga wire? 10-2 with ground NM-B cable, (Romex)?
Were the parallel home runs separated from one another or pulled in a clustered group?
Approximately what is the average length of the home runs from panel to outlets?
Were the home runs kept away from parallel run/s of lighting circuits? Especially load side lighting circuits fed from dimmers?
If you get the chance will you run the noise test with the dedicated circuits used feeding the equipment and with only one dedicated circuit to power the equipment. Do you have something you can use to introduce noise on just one dedicated line and then check to see if the noise intensity is the same on the other 3 dedicated branch circuits?
Jim
Edits: 06/02/17
These were run with stranded, individual wires, in a buried PVC conduit...but they may all be in the same clustered group, but the buried PVC only has runs for the audio gear in it.
I do not have a noise sniffer any more and my 1960's vacuum tube spectrum analyzer is too heavy and bulky to lug anywhere!
The run is about 40' and nothing else runs nearby or parallel to it.
It does sound tons better than what was there before, but due to the house guests I have not been able to work there in over a month...it had only been in a few days when the guests arrived, so I don't have much time with it at all...
These were run with stranded, individual wires, in a buried PVC conduit...but they may all be in the same clustered group, but the buried PVC only has runs for the audio gear in it.
Hi Rick, thanks for the response.
Though it may sound better than what your friend had before it would more than likely sound even better had he not used the wiring method he used for his 4 new dedicated circuits.
A true dedicated branch circuit does not share the same conduit or cable assembly with any other branch circuits. The reason they should not be installed in the same conduit is the current carrying hot and neutral conductors will induce a voltage onto the other conductors in the same conduit. The same for any AC noise/harmonics that may be present in a circuit caused by a piece of audio equipment.
Even when a dedicated branch circuit is pulled in its' own conduit if the hot and neutral current carrying wires are just loosely pulled in the conduit with an equipment grounding conductor an induced voltage can be induced on the equipment grounding conductor. The induced voltage on the equipment ground can be the cause of a ground loop hum and or noise on the equipment ground conductor.
When a conduit is used it is recommended the hot and neutral wires should be twisted together the entire length of the conduit run. The equipment grounding conductor should just be pulled along side the twisted hot and neutral pair. (Note: Will twisting the hot and neutral together and then pulling them in a conduit meet NEC or local AHJ electrical code? I am not sure. I am sure the twist of the 2 wires should not be too tightly twisted together. That will not meet the manufacture intended use of the wire and therefore not meet electrical code).
I am not a fan of stranded wire either for branch circuits that feed audio equipment. I recommend solid core. #10 solid copper can be a pain to work with though.
.
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Here is a long winded experiment I conducted a couple years ago on harmonics caused by an incandescent light dimmer. The test equipment was just a simple phone tone receiver used to find twisted pair phone cable pairs.
The noise generator I used was a wall incandescent Lutron dimmer. The branch circuit feeding the lighting is a dedicated circuit for the lighting in the room and lighting in a bathroom. (14-2 with ground Romex). With the dimmer set at about 60% the harmonic noise radiating from the dimmer was quite audible. I was able to follow the load side branch circuit wiring up the wall to the 9ft ceiling and to each of 7 can lights mounted in the ceiling of the room.On the same wall as the dimmer is another dedicated circuit that passes/parallel on the same wall stud with the lighting circuit that is used for general convenience outlets in the room. The dimmer harmonics corrupted the entire convenience outlet branch circuit run in the room.
As for the home run lighting branch circuit wiring feeding the dimmer as I moved from the dimmer to the electrical panel the audible sound of the receiver got weaker the closer I got to the electrical panel. The home run is about 60ft long. Wire is 14-2 with ground NM-B cable. (Romex is a Trade name.)
At the electrical breakers around the breaker feeding the dimmer branch circuit the audible sound was fairly even. As I moved the receiver further away to other breakers the audible sound was somewhat weaker but not by much.
From this same electrical panel I have 2 dedicated circuits that feed my 2 channel audio system. The 2 home runs are about 75ft each. Wire is 10-2 with ground NM-B cable. With the dimmer on, set at 60%, I held the receiver at each duplex outlet of the 2 circuits. All I could hear was the faint normal 60Hz hum of the AC line picked up by the receiver. I could not detect any dimmer harmonics.
What I discovered is the harmonics produced by the dimmer dissipated the further I got away the dimmer to the electrical panel and continued to dissipate the further I got from the panel to the wall duplex receptacles of the 2 dedicate circuits feeding the 2 channel audio equipment.
I should also note the 2 audio dedicated branch circuits were intentionally installed away from any other parallel running branch circuits. Especially any lighting branch circuits Line as well as load. I also kept the 2 dedicated audio circuits separated from one another, parallel run, as soon as possible after getting out of the electrical panel. At least 60ft of the 75ft runs are kept separated from one another. (This eliminates induced voltage transfer as well as AC induced noise from one cable to the other.
.
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Below is a white paper well worth reading.
check out page 16 and then go to pages 31 through 36.
Edits: 06/03/17
I absolutely agree on the separation of runs, but the homeowner had the ultimate discretion on what was to be done, and the trenching and installation was how he wanted it, we just did what the homeowner would go for...I got him to go with four instead of just one or two, so at least that was a small victory...all four circuits are in one 4 gang outlet box.
I did what I could to improve the electrical current delivery in this artistically engineered $1.5 million+ home (Texas evaluation NOT California) and kept within the parameters set by the homeowner.
That's all one can do, right?
All you can do is suggest what you think will work best for the guy.
Best regards,
Jim
Hi jea48,
Just a tip to share with you.
Cheers, Duster
See link:
By chance have you bought one? The outlet looks well built. Great price!
I wonder what is used to reinforce the gold plated copper female contacts so they retain their holding pressure?
Jim
I was lucky enough to find one when it was first released before it was plated with gold or rhodium. I use the unplated version and the gold plated version. It's a HQ product, pretty much the same as Cardas, AudioQuest, and Pangea offer, with various base metals and plating schemes.
It's the first and only true low-cost Audio Grade AC outlet. Pretty much a near-perfect knock-off, but not at the performance-level as the Furutech design it's based upon.
The brass back strap is massive, far better than any hardware store AC outlet, and the polycarbonate body is very solid and rigid. From what I gather, the base metal is phosphor bronze with excellent grip, but the contacts don't dig into an AC plug blade like a hardware store AC outlet tends to do.
nt.
I would like an AC delivery expert such as yourself to evaluate this product, if you don't enjoy Audio Grade AC outlets, as of yet.
Cheers, Duster
If you lived "across town", I would love to see your oscilloscope in action, and learn something! I've never used one. So I know zip...
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