Measuring AC Power Line Noise

Jim Smith

Jim Smith

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Atlanta, GA
Have been tempted to try Shunyata Denali, but my power line has its' own dedicated feed directly from the transformer 20' outside the listening room. Sound, by all accounts - not just mine - is outstanding - very dynamic & pure.

But most of us have a case of the "What ifs" - including me.

Since Shunyata shows AC power line noise as an issue, I wonder if anyone has - or has used - an affordable device to measure "before and after (installing the Denali)" power line noise?
 
Jim Smith said:
Have been tempted to try Shunyata Denali, but my power line has its' own dedicated feed directly from the transformer 20' outside the listening room. Sound, by all accounts - not just mine - is outstanding - very dynamic & pure.

But most of us have a case of the "What ifs" - including me.

Since Shunyata shows AC power line noise as an issue, I wonder if anyone has - or has used - an affordable device to measure "before and after (installing the Denali)" power line noise?
Click to expand...

Entech Line Noise Analyzer. That's what I use. I've heard the same from clients. I take the Entech to their house (and a Denali or AQ 1000/5000/7000) and the before and after is not subtle.

https://youtu.be/LxyxkCOlZsU


Sent from my iPhone using Tapatalk
 
Thanks! Already ordered Trifield PLM (Power Line Meter). For whatever reason, was thinking the Entech was no longer available.
 
Mike said:
Entech Line Noise Analyzer. That's what I use. I've heard the same from clients. I take the Entech to their house (and a Denali or AQ 1000/5000/7000) and the before and after is not subtle.

https://youtu.be/LxyxkCOlZsU


Sent from my iPhone using Tapatalk
Click to expand...

The Enteq is no longer being made. However, you can find some used ones on the eBay. The Enteq is useful for rudimentary demonstrations. However, it is not a good device for a comprehensive study of power line noise. First, it is has no standard references settings. You plug it in - you adjust the gain with the knob until you get a approximate 100 reading on the meter. This is arbitrary - not a measurement where you could compare two different power lines and certainly not compare readings between locations. It is however useful for a quick before and after of the same power line. You must be careful NOT to touch the gain control between readings and the readings should be taken very close together since power line noise is dependent upon the radiated RFI/EMI noise in the environment.

A Fluke Model 43 power line analyzer is relatively inexpensive but it doesn't measure noise.

For actual scientifically accurate readings you need a spectrum analyzer that is specifically setup to do power line readings. We several including the Audio Precision Analyzer with power module installed. If you have a PC based spectrum analyzer DO NOT plug it into your power line! If you don't know what you are doing - don't do it. You must take very specific precautions when connecting measurement devices to a live power line.

The Enteq only detects and rectifies frequencies to around 700KHz which means is it completely insensitive to some of the most harmful noise frequencies - those in the 1MHz to 10MHz ranges. But hey it is inexpensive, easy to use and it is nice to be able to "hear" some of the stuff that is on your power line. Your dedicated power lines, rhodium plated outlets and large gauge wires in the wall in no way immunize you to power line noise. Power line noise is picked up from radiated electromagnetic waves all around you. This includes AM and FM radio, wifi, cell frequencies and the list goes on. Furthermore noise reduction is always "localized". That means that just because you have a power conditioner that reduces conducted noise does not mean that the noise doesn't re-introduce itself farther down the line. So if you have some form of power conditioning at the electrical panel, the radiated noise will be picked-up by the in-wall wiring that acts like an antennae. This means you WILL have noise on the power line at the wall outlet. This is why we talk about the "distributed power conditioning" approach to noise reduction.

We are actually working on consumer level device that is more a modern and elaborate version of the Enteq. It will detect a broader range of frequencies and they will be calibrated so that absolute readings can be taken. This will allow you to see if you have a low, medium or high level noise on your line. And it will allow people to compare noise levels at different times of the day and at different locations.
 
Jim Smith said:
Thanks! Already ordered Trifield PLM (Power Line Meter). For whatever reason, was thinking the Entech was no longer available.
Click to expand...

Jim, I just looked up the Trifleld. It looks like a good device and it measures out to the important frequencies. I am ordering several for our demonstrations also. Let's see how well it works.
 
The Entec for ~$50 used is certainly not the end all and be all, but what it does is vocalize the noise and when consumers HEAR the noise on their line, it's much more impactful than if they see something on a gauge. With a gauge they say "yeah, but do I really hear that?" With the Entech's speaker vocalizing the noise, they hear it!


Sent from my iPhone using Tapatalk
 
Jim Smith said:
Have been tempted to try Shunyata Denali, but my power line has its' own dedicated feed directly from the transformer 20' outside the listening room. Sound, by all accounts - not just mine - is outstanding - very dynamic & pure.

But most of us have a case of the "What ifs" - including me.

Since Shunyata shows AC power line noise as an issue, I wonder if anyone has - or has used - an affordable device to measure "before and after (installing the Denali)" power line noise?
Click to expand...

Jim,

I'd began from spectrum analysis of analog output of pream or power amp.

I seen video with demostration of power line noise meter. It's cool. But it is not matter for audio devices in the first approach.
Because audio device's power supply unit (PSU) should (if it work properly) suppress these interferences, that measured by powerline noise meter.
Of course, need check this for exactness.

But for end-user important noise at analog output of audio system. If connecting power conditioner or other filter decrease total noise level or remove noise fragments/harmonics at analog output of the system, this conditioner recommended for using.

If connection AC filters don't impact to output spectrum, have no sense connect input AC filter.

Also recommended check spectrum at internal DC powerlines of audio module for impact to external AC filter.
 
YuriKorzunov said:
Jim,

I'd began from spectrum analysis of analog output of pream or power amp.

I seen video with demostration of power line noise meter. It's cool. But it is not matter for audio devices in the first approach.
Because audio device's power supply unit (PSU) should (if it work properly) suppress these interferences, that measured by powerline noise meter.
Of course, need check this for exactness.

But for end-user important noise at analog output of audio system. If connecting power conditioner or other filter decrease total noise level or remove noise fragments/harmonics at analog output of the system, this conditioner recommended for using.

If connection AC filters don't impact to output spectrum, have no sense connect input AC filter.

Also recommended check spectrum at internal DC powerlines of audio module for impact to external AC filter.
Click to expand...


Do you suppose that significantly reduced noise on the output of a million dollar medical imaging system might quality as evidence?
Do a little research - please.
 
Hi Caelin,

Sorry, I don't understand, what kind of researh you suggest?

Does you mean what positive result at output one system obligatorily lead to positive result at other system?
I suppose, reducing of noise floor for one system, probably give reducing for other.

At my past work in radio communication branch, we are used AC filters.
But we checked it for each system for impact to noise floor at output spectrum, because there was used different power supply units, construction, schemes/devices, AC sources, etc.

P.S. As I understand, AC power conditioners is part of your business and you are expert in noise suppressing.
For me will interesting discuss with you the noise suppressing issue. It is way to get first-hand information.
 
YuriKorzunov said:
Hi Caelin,

Sorry, I don't understand, what kind of researh you suggest?

Does you mean what positive result at output one system obligatorily lead to positive result at other system?
I suppose, reducing of noise floor for one system, probably give reducing for other.

At my past work in radio communication branch, we are used AC filters.
But we checked it for each system for impact to noise floor at output spectrum, because there was used different power supply units, construction, schemes/devices, AC sources, etc.

P.S. As I understand, AC power conditioners is part of your business and you are expert in noise suppressing.
For me will interesting discuss with you the noise suppressing issue. It is way to get first-hand information.
Click to expand...

No arguments from me. Some power supplies are definitely better than others. Power supply design is often one of the most important in high-end component design.
 
IF the Trifield works (mine is enroute but not here yet), seems as if it would be a good tool for dealers to have on hand, perhaps as a loaner or even a rental, (fee carried forward as credit if purchase of conditioner is made).

Since I am not a dealer, that's easy for me to say, it's just a thought... :)
 
Jim Smith said:
IF the Trifield works (mine is enroute but not here yet), seems as if it would be a good tool for dealers to have on hand, perhaps as a loaner or even a rental, (fee carried forward as credit if purchase of conditioner is made).

Since I am not a dealer, that's easy for me to say, it's just a thought... :)
Click to expand...

Jim, you are right. It is only $130 which any dealer should be willing to invest in.

We have received three of them and will be testing to see how useful they are. One caveat, as with all measurement tools especially simple ones there may be a tendency to rely on a single parameter to make decisions. All of these type of devices will only give a rough (averaged) reading of noise on the power line. There is no way with these to know "which" frequencies are actually on your specific line. And of course the noise components between locations and cities will be different. So as with the Enteq, this will be primarily useful to hear/see "relative" differences on a specific line at a specific time.

That said, it looks like a useful tool to have at your disposal. For example, using the Enteq at my house I found that I had a very strong radio station being picked-up by my upstairs power lines. I also could hear the very distinctive sound of LED lighting noise pollution. Quite insidious actually.
 
CGabriel said:
No arguments from me. Some power supplies are definitely better than others. Power supply design is often one of the most important in high-end component design.
Click to expand...

The PSU is what you are mostly listening to , the amplifier is the oscillator .... :)
 
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