AC mains noise Borrowed noise sniffer and tested my AC lines...

Interesting indeed. I have been looking at different AC conditioners and power distribution strips, e.g. Shunyata, synergistic Research, Cardas, etc. My thought is to replace my 2) Running Springs units to save space. I have looked for a Noise Sniffer as Elizabeth has been fortunate enough to obtain. 
Obviously too expensive to own for a one time purchase. It would be nice if Audio stores or manufacturers would offer rental on such devices to help sell their products.
That aside, I have a question for Elizabeth, not knowing how long you have possession of this device, but if you could let us know how the readings vary at different times of the day. And when you get a low reading on one component do you plan to test one of the higher reading components as close to the same time? It could reveal just how much the electricity coming into the house fluctuates thru the day.

Use of the device while place is closed. Late Saturday until early Tuesday only.     
I am not going to bother test all day.. It IS Sunday. Only possible change might be on Monday.. But not much here. I might if I fel like it. But no way comprehensive checking.           
As for 'making the sound bad with PS Audio Noise Sniffers'. Yes, the can, location IS important. And the usual problem of lean sound due to too much filtering is well known to me. Any of the various filtering devices, overdone, can damage the sound. Mainly by making it thinner, tighter, leaner bass,.. You name it.      
The question: "What does it mean" Philosophical?? I guess what it means is the noise was lower at taht outlet at that time, curiously while music was being played.when music was being played. Period.If you cannot live without knowing why, you are SOL here.      
This Morning I an unplugging everything to get a baseline of the actual wall I take the AC from, and each stage asI plug stuff back in. Also searching for the 'worst offenders' injecting garbage back in. (Like the Laptop charger, known bad. And where the AM music is being injected on the separate Adcom power conditioner used for the cable and WiFi etc. Adcom may be moved off stereo AC? if it is not stopping this stuff.

For a less expensive alternative you might try this Power line Meter direct from AlphaLab:

https://www.alphalabinc.com/product/plm/

I sold my expensive Akiko Corelli Passive Conditioner when I found it actually increased lpower line noise.

I hope this helps!

I have an Alpha Lab Power Line Meter and it is fun to see the different numbers being generated with different circuits, different equipment and at different times of the day.

But I have trouble correlating these numbers with differences in how the music systems sound. I also have the PS Audio Harvesters and they (as Elizabeth pointed out) are not simply plug and play. They may make the sound better, worse, or unchanged. Chasing numbers does not lead to better sound.
David Pritchard

Ok did all the baseline measurements.                  
At wall, nothing plugged in a 20amp single on a separate breaker: Noise "724" .That line is one phase sharing common neutral with other phase 20 amp for refrigerator. I wondered how much of a problem that ’common neutral’ made. Well almost zero!           
The stereo line at wall with frig ’on’ noise "724" (frig off ’710’ frig break off noise "711" so the frig is a non starter of a problem. VERY good to know.)              
Plugging in the two lines made up of 12 gauge MilSpec silver plated quad twist Teflon 600V wire. grounds run between the two quads. 34 feet and 44 feet to stereo area. From the noise readings, it is clear the quad twist all by itself is removing a good amount of the hash from the line.             
At the 34’ line end Furutech duplex (no Noise Harvesters) noise "432" With two PS Audio Noise Harvesters in line a few feet ahead of duplex measured at, noise "006"         
The other line for the amp at 44’ (With two Noise Harvesters in a duplex four feet from the measured duplex) the noise level "001"(amp not plugged in. for those tests nothing was plugged into any outlests except the Noise Harvesters.            
So outstanding noise reduction from the wall ("724") down to ("006") and ("001") on my dedicated line from the wall to the stereo.               
+++++++++++++++++++++++++++++++++++++++++++++++++           
Plugging in the PS Audio P-600 power regenerator to the 34’ line changed the measurement at the Furutech outlet to "036" with P-600 ’on’ (nothing in use via P-600) With TWO CD changers also ON via the P-600 the noise at the Furutech 34’ outlet changed to "040" So I consider that wonderful performance. None (well ,very little to me is as good as none) of the considerable previously measured noise from the CD players is getting BACK to the outlet via the PA Audio P-600 regenerator.               
+++++++++++++++++++++++++++++++++++++++++++++++++           
Adding the Furman power conditioner OFF nothing plugged into the Furman noise measured at the same 34’ line Duplex "063" PLUS AM radio noise on the test instrument. (the PS Audio was also already plugged in and ON for this test. so the Furman alone added only ((023)) on it’s own to the noise level.  When I turned ON the Furman REF 20 the noise dropped to "035" No AM radio noise anymore. (again, this is with the PS Audio plugged in too, so the Furman ON lowered the noise floor below what the PS Audio added. plus the Furman ON removed the AM radio noise on the line.)              
With Furman all electronics plugged on but those not turned on, only Furman turned on. At the 34" duplex noise measured "042"         
With all normal stereo equipment turned on the 34’ duplex measurement was noise "036" The items on included several preamps, and the Mrantz SA-10. (not turned on two Denon DVD players, The plasma TV. the Kuzma TT motor power supply I did not measure for those)              
++++++++++++++++++++++++++++++++++++++++++++++           
Small Adcom conditioner used for little stuff plugged in (with both big conditioners on at the 34’ duplex noise "060" plus AM radio noise.I removed the Adcom and substituted a Monster 5600 I own in it’s place, The Monster on with nothing plugged in gave at 34’ duplex "045" ... With all stuff plugged in in use (including the cable co boxes) measured at 34’ duplex "054" So I am leaving the Monster in            use.+++++++++++++++++++++++++++++++++++++++++++++++            
Finally my Audio Research SP-15 I had left plugged in at the 34’ box mainly due to the short cord. With it plugged in at the 34’ box at the 34’ box both conditioners in and on measured noise with Sp-15 in not ON "082" plus AM radio noise. ARC SP-15 ON measured "081" no AM radio noise. I removed the ARC SP-15 from that location and put back with extension cord to Furman. I did not measure anything when I did this.  
++++++++++++++++++++++++++++++++++++++++++++++++++ 
as of now, my Rega turntable power supply wall wart sits with no place to plugin. Orphaned when I decided to plug the two PS Audio Noise Harvesters into that spot it had used...   
Also I do not notice the downside of using the additional Noise Harvesters in the 34’ line. Previously I had them AT the two duplex on the end of the line. This time I moved them to the single duplex at the 31’ point.on the 34' line.. similar to the amplifier line. Why this matters??? seems to.    
I have no magic comments on this stuff at this time. I just wanted to report the numbers.