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[Brandt]

Oh...you can isolate circuits?!? It looks like this circuit 11 is a prime candidate to be isolated!!

When we had this house built, I added one or two receptacles in each room for electronic equipment, and had the electrician wire those on a separate circuit.  That circuit is now fed from a 2200VA true-sinewave UPS, which itself is isolated with the big X10Pro 20A XPF filter.

To identify those receptacles, they are a different color from all other receptacles.  They power the computer, TVs, DVRs, audio system (except the 800W power amp), and small plug-in "wall-wart" power supplies.

Jeff

so what is the affordable way to isolate a circuit? just the XPF? I wonder though, because I tried the 20amp ACT filter on the big screen and equipment it supposedly affected the sound....would I hear the same complaint if the whole circuit was filtered at the breaker?

[JeffVolp]

Yes, the XPF is the way to isolate a circuit.  However, any X10 devices on that circuit will also be isolated.  The XPF is a large filter, and is normally installed in a deep triple-gang electrical box.

Whether it impacts your sound system depends on whether you tell anyone about it.  The XPF is a 120KHz notch filter.  It will block signals around 120Khz from passing through it, but it has low resistance to the AC powerline.  I just measured one, and had less than 0.1 ohm DC resistance, which is the limit of my DVM's resolution.

Jeff

[Brandt]

Whether it impacts your sound system depends on whether you tell anyone about it.  The XPF is a 120KHz notch filter.  It will block signals around 120Khz from passing through it, but it has low resistance to the AC powerline.  I just measured one, and had less than 0.1 ohm DC resistance, which is the limit of my DVM's resolution.

Jeff

hmm maybe a picture would help 

[Brandt]

Well, the washing machine sure killed the X10 signal..took care of that one...

still some weak areas, in the living room I moved the lamp module to the same receptacle that the x10 switch is controlled by, only the bottom outlet that is not on the switch. I also adjusted the receive sensitivity level of the x10 switch (pcs scenemaster)

Any good docs to read on receive sensitivity? There were thresholds available from 5mv to 350mv. The default was 50mv and i changed it to 10mv since there was a low x10 signal at the outlet.

[Brian H]

Yes we seem to be seeing more appliances. Like washers with electronic controls. Being signal suckers or noise makers.

[JeffVolp]

If the module can detect a 5mV X10 signal, it can also be blocked by just 5mV of noise.  I am not familiar with the PCS products.  Unless they incorporate some form of AGC to raise their detection threshold above the background noise level, 5mV or 10mV sensitivity is asking for trouble with all the electronic equipment and CFLs in a typical home today.

Regarding your earlier question, here is the XPF document:

          http://www.x10pro.com/pro/pdf/xpf.pdf

(Google is your friend.)

Jeff

[Brandt]

Well I have the XTB-IIR and x10 filters on *almost* every suspect and signal levels are still under X1.00 on some receptacles. I would really like a drastic improvement if possible...I'm getting sick of things not working to where I almost give up sometimes.

I already have a feeling the a/v equipment in the living room is hurting things but I can't do much there.

What about things like the dishwasher, microwave, refrigerator, garbage disposal, oven, central heating unit, and outdoor a/c fan?

Am I possibly losing some signal out on the street?

What else?

Ugh!! 

[JeffVolp]

Actually, a 1V signal level should be fine.  If things are not working with that much signal, then those modules are probably being blocked by noise, possibly on the same circuit.

X10 modules operate reliably down to 100mV, and maybe even lower.  Before installing the XTB, we had one circuit here with signals of about 100mV (as indicated with 1 bar on the ESM1).  Everything on that circuit still worked fine.

It is possible that some of the equipment you describe might be causing problems.  A dishwasher might have electronic controls with a switching power supply.  Same for the microwave and refrigerator.  Some of the newer HVAC systems have variable speed blowers that have been reported to generate a lot of noise, and have to be isolated with a XPF filter.  The outdoor A/C compressor and fan should not cause a problem.  I don't think the oven or garbage disposal would either.

Anything with a switching supply can be producing noise.  You just have to track it down.  At some point you should just disconnect that A/V equipment to see what impact it has.

Some of your signal will certainly be leaking out to the utility transformer, and possibly to neighbors sharing the same transformer.

Jeff

[Dan Lawrence]

This is an interesting thread.   As to X10 signals crossing through a transformer, since X10 is NOT mass marketed, it is highly unlikely that two houses next door to each other would both have X10.

I've been using X10 since the middle 1980's and no one else on my block uses X10.  Even though Radio Shack sold X10 under their label as "Plug & Power", they never sold interfaces, only desktop controllers. 

[Brandt]

ok we tested the ACT AF120 again on the high end stereo and could still here a difference. The problem is the http://www.changlightspeed.com/ which is a signal sucker...The X10 signal at one receptacle went from ~X5.00 to ~X0.60 with it in place. the AF120 notch filter helped, but again affected the sound due to the fact that it was placed between a gold plated receptacle and a very expensive power cable the thickness of a medium sized snake. He said that if the filter could be put behind the receptacle than it would probably be ok. The only filter type thing that goes behind a receptacle that I've found is this http://www.smarthome.com/4840/Leviton-In-Line-Noise-Reducer-6289/p.aspx which doesn't seem to be what I'm looking for...or is it?

The other option would be this http://www.smarthome.com/4834/20-Amp-3-Wire-Noise-Filter-XPF/p.aspx at the breaker for the whole circuit correct? I'd really rather not block off a whole circuit from X10 usage if possible, but if it is the only way than so be it...


or this behind the receptacle? http://www.smarthome.com/4835/Leviton-Noise-Block-6287/p.aspx


Also, I think it important that they are notch filters and not high or low pass filters...

[JeffVolp]

See my post back on August 6 regarding the XPF.

The 6289 can attenuate wideband noise from things like universal motors, but will not do much for a noise source near 120KHz.

The 6287 is essentially a 5A version of the XPF.

Most receptacles are wired with 14 gauge solid wire, which has a resistance of 2.58 ohms per 1000 ft.  Household circuits are normally daisy chained from one receptacle to the other, so the total wire length from a typical receptacle to the distribution panel can be much more than one might think.  Even a special circuit that feeds one load, such as a refrigerator, microwave, or window A/C, can be longer than expected because of the way the wire must be routed.  So, a receptacle 20 feet from the distribution panel will probably have a round-trip wire length of 60 feet or more.  It might even be well over 100 feet.  Using 14-gauge wire, the resistance would be at least 0.15 ohms, and perhaps over 0.25 ohms.  A straight run of 12-gauge wire would reduce that to about 0.1 ohm.

I previously measured the resistance of the XPF below 0.1 ohm, which is the resolution of my meter.  I just tested it again running 1.0A through it from a DC power source, and the drop across the filter was 10mV.  That means the resistance is only 10 milliohms, which is reasonable looking at the size of the inductors.  The drop across the filter would be insignificant compared with the drop in the powerline itself.

I don’t have a ACT AF120 myself, but I would expect its resistance to be no more than 20 milliohms.  If so, a load pulling 10 amps (1200 watts) would have an average drop of just 200mV out of 120V.   I don’t understand how that could have any effect other than psychological on the performance of even a high-end audio system.

I’ve been in the electronics field my whole life.  I designed my own 800w rms amplifier back in the 70’s that is still in service today.  It can dim the lights on heavy bass.  All you need for good sound are heavy copper conductors going to the speakers.  In my case with 4-ohm speakers, those currents are far higher than the current pulled from the powerline.  While those gold plated connectors are pretty, they really don’t do much technically.  Their primary advantage is to prevent corrosion in a high moisture environment, which CAN affect the performance.  For more on speaker wire:

     http://en.wikipedia.org/wiki/Speaker_wire

Demands on the powerline are less stringent than the speaker cables.  The amplifier will draw its energy from large electrolytic capacitors.  Those are recharged each half cycle from the AC powerline.  All the resistance from the utility transformer through the house wiring and then through the power supply internal resistance will contribute to sag in the power supply when delivering the loudest notes.  Another 10 or 20 milliohms from an in-line X10 filter would be insignificant.

Jeff

[Brandt]

I'm going to try and explain this the best I can from the conversations I've had with my Dad the audiophile:

When listening to a high end audio system, and high end audio recordings there is something called a sound stage or audio imagery. The recording engineers (in a studio recording) will try and place an instruments recording on this sound stage not only on left or right coordinates, but + or - phase coordinates sort of like an X, Y, and Z axis. On a live recording they leave it natural as every concert hall will have it's own sound signature. The recording tries to capture every little overtone and harmonic of an instrument such as with a guitar; what type of pick is being used (hard or soft), what kind of strings are being used, the wood the guitar is made out of, the size of the room the guitar is being played in, etc... There may be other things that an audio recording engineer may be trying to capture also, but instrument placement and undertones were the two things discussed.

Now onto the electrical aspect:

The wiring in the house can not be controlled due to renting the house, if it were possible my Dad would like a straight stand alone 30 amp run to his stereo system. Everything that can be controlled and replaced in the electrical run has been (the receptacle, the power cables, the fuses, (wishlist: capacitors), etc). If you put an ACT AF120 filter between the receptacle and the power cables that becomes the weakest link. The electrical qualities of the AF120 may include some cheap solder or cheap capacitors. The difference is in the smelting process of alloys, where impurities cause the electrical signal to have to go around them instead of a straight shot which is the difference between $50 electrical components and $0.10 components. The electrical path and audio signal having to maneuver around impurities will cause vibration and/or jitter in timing in the sound which collapses the sound stage and other audio qualities.


If a notch filter can be put behind the receptacle, that may or not make the difference.

[JeffVolp]

I'm sorry, but I have to disagree with this from a strict engineering standpoint.  The AC power to the audio system can have absolutely no impact on the harmonics produced or the spacial relationship between the speakers.  Likewise, solder impurities in a filter will have no impact.  All that matters is the DC resistance betwen the utility transformer and the rectifier that pumps power into the amplifier's filter capacitors.  And that only matters when producing the loudest sounds - chest vibrating bass.  Some extra resistance in that path may mean the maximum sound pressure is a tiny fraction of a db lower than it would be if the amplifier was wired directly to the utility transformer secondary.

I know there are audiophiles who worship oxygen free wire and gold connections.  But from a strictly engineering standpoint, they are only wasting money.  There are companies that service that market just like there are companies that produce "label" purses for hundreds or thousands of dollars.  It is all about status.

Doing a quick Google search on gold connectors and oxygen free cables turned up a couple of interesting reports:

     http://www.aqdi.com/goldcon.htm

     http://www.practical-home-theater-guide.com/speaker-wires.html

They are worth reading by anyone contemplating investing in expensive audio cables.

Jeff

[Brandt]

Yup he thought is was all snakeoil at first also, but then he heard the difference. Anyway the only way I can filter his signal sucking power strip is behind the walls ;-)

[Brandt]

Will the Leviton 6287 also filter all the receptacles that are daisy chained off of it, or only the receptacle in which it is wired directly behind?