How noisy is my line? Audio Prism Noise Sniffer


A friend and audio journalist had this Prism device, and he plugged it into various outlets when I visited him. It gave a clear sense of which outlets were noisy and how effectively his conditioners were helping with noise.

 

He said these were not made any longer. Does anyone know of another tool like this?

It seems like it could save someone with clean power (or a quiet outlet) a lot of money from conditioners/regenerators which would not necessarily help.

128x128hilde45

Google “powerline noise analyzer” or “powerline noise sniffer.”  The typical meter has a numerical readout in some units, such as parts per thousand, and they also have a mini speaker that plays a demodulated form of the noise so you can identify the source as radio interference or a motor or electric arcing, etc.  

There are at least a dozen models available.

@larryi  Thanks. It's interesting to me that these tools are nearly never mentioned when discussions of conditioners, etc. are flying around.

Post some adress of this product here if you can have  one or two...

Thanks.

There are at least a dozen models available.

 

These observations are interesting:

https://www.audioshark.org/power-conditioners-regulators-24/measuring-ac-power-line-noise-11713.html

 

Just an extract of this very informative thread... :

 

«The Emtech 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. »...........................................................

«I have several of the Alpha and the Stetzerizer units. Personally, I prefer the old Entech unit. Entech was actually a very technically advanced group of engineers. Both the Alpha and Stetzerizer are similar in that they have a bandwidth that extends quite low for measuring RFI/EMI. They drop down to 15-30 kHz in there measurements. While this may seem to be an advantage it actually has a fatal flaw. Both aggregate noise from about 15 kHz to around 10 MHz and lump them all together in a single reading. Some frequency bands are more important to the performance of audio equipment specifically our research indicates the the most harmful frequencies are in the 100 kHz to around 1 MHz bands and then secondarily from 1 MHz to 10 MHz. Interestingly, I believe that the Entech engineers knew this and designed their device to be sensitive in the frequencies from 300 kHz to 700 kHz range. This makes the Entech particularly useful for finding noise sources in the specific ranges that are most noticeable in the context of music systems.

I have done direct side-by-side comparisons using all of the units listed. I would then plug a device into the power line that we ’know’ produces particularly harmful noise effects as measured by our power and spectrum analyzers. In many cases, the Alpha and Stetzerizer would barely change their relative readings while the Entech would go off the charts. This is because the Entech is more narrowly focused and the other two are less so.

And then conversely I would connect filters that reduce power line noise in a known manner as verified by the power and spectrum analyzers and in many of these cases the Alpha and Stetzerizer would show only as small or marginal difference while the Entech would show a much larger and significant difference.

Look these are all very inexpensive devices and all of them can be useful. But they have severe limitations from a technical point of view. I found the most useful for the hobbyist to be the Entech. As I said earlier, we are developing a device that will be much more useful and will show noise in specific bands much like the old audio spectrum displays. This is being developed for our medical division where this device will be quite useful in identifying specific types of noise pollution in hospitals. I hope this is helpful.

BTW, I have three of the Alpha units and would be happy to sell two of them at less than what we paid for them. Just PM me.

Caelin Gabriel President Shunyata Research

There is a huge, literal gap between professional power quality meters such as by Fluke and audiophile toys. The gap is in the frequency band they cover. The pro’s measure noise and distortion in the range of motor frequencies and the audio band, and the range we care about for power supplies.

The toys they sell audiophiles are usually poorly specified or measuring noise so high in frequency we may never even hear it.

Chasing down a 1 MHz RF signal is a rabbit hole that can send you down spending money you don’t even need to spend.

This is one major reason I like surge and noise filters from Furman wiht SMP and LiFT, as well as the series mode protectors by SurgeX, etc. The series protection starts filtering down at 3 kHz, while many RFI/EMI filters don’t even work below 100 kHz.

My other bit of advice is to separate out noisy wall warts and keep them away from the clean side of your power conditioners.

If you _must_ invest in these power noise ... gizmos, at least find out the range of frequency at which they are working at, so you know what the signals mean.

I had a demo of the audio sniffer thingy.  It really worked.  Plugged into outlets and they were quite noisy.  Then plugged into a power conditioner and which had barely any noise coming from the sniffer.

Pretty sure I don't need a sniffer to know that line power is dirty.  The power on the grid in my neighborhood is about 4% THD.  The output of my regenerator is .1% THD.

Jerry

@thecarpathian Yes, I'm still very impressed and satisfied with the Ascend ELX towers. They are the equal of a bunch of other speakers I've heard -- to my tastes -- including Wilson, YG, and others. Their synergy with my Quicksilver mono 60s and Pass XA is excellent. I'm still wishing I had kept the Fritz Carbon 7's but that may be a second speaker at some point.

I saw the meter reading and demodulated noise from the meter speaker on a dedicated line running from a very expensive dedicated subpanel.  There was still, somewhat high level of noise, that was substantially reduced by a powerline conditioner.  The system had no audible noise, as such, without conditioning, but the sound did improve with conditioning—particularly with respect to creating a soundstage that seemed to float in space.  The meter being used was an Isotek meter, which is not cheap (about $1,000), but, $100 meters seem to work the same way.

@hilde45 ,

  Glad to hear it.

Still using the Quicksilver pre?

How do you rate those Salks against the Carbon7?

Sorry for all the off topic questions, but you’ve got a lot of gear I’m curious to hear about!

I had the Carrera’s but could never tame that beryllium tweeter.

Thanks to posters about the meter. Yes, it's crude. It's probably enough for me to get a very general impression of my various lines. The idea that I need a much more elaborate meter is based on uses I have not contemplated and are likely irrelevant.

@thecarpathian 

I got rid of the Quicksilver Pre in favor of a DIY based around the DeHavilland Ultraverve III. 6SN7 tubes are preferable to my ear.

I like the Carbon7 better than the Salks, not least because of the Be tweeter in the Salks. The Carbons have a really gentle and musical (that word!) touch. I have noticed a couple video reviews on the Carbon 7 recently.

Buy a digital oscilloscope for under $400 and learn how to use it. Way more informative and useful, way less woojum.

I use the Enteq as a general sniffer.  I then plug it into a conditioner to see how quiet it is relative to the noise.  In my observations the Puritan 156 is quieter than the Furman reference 15i.

Audio electronics do not run on 110 volts AC. They run on DC from 5 volts on up. The job of any well designed power supply is to filter out all AC and regulate the supplied DC voltage accurately.  If any "noise" (which is AC) gets through sell it and get a piece with a decent power supply. 

Having said that there are instances were filtering can make a difference. As an example, the high voltage power supplies that charge the diaphragm of electrostatic loudspeakers is very simple. There is no current involved. It uses a step up transformer to get to 250 volts AC then a voltage amplifier of serial diodes and caps to get to 6000 volts. Any noise online might be amplified in the process and affect the diaphragm's performance. 

@panzrwagn  Do you know of any digital scopes with really easy to use/nice to use spectrum analyzers?  When I last had one the spectrum analyzer was a real chore to use, so hard to evaluate the types of noise I was looking at.

@eric_squires Any test test equipment that provides quantitative data will require some degree of technical capability by the user, but I agree, many do require a little too much Electrical Engineering background, not to mention significant capital outlay.

Take a look at this software only package though, 

 

You'll need an interface like a Focusrite Solo or 2i2 and a patch cable for line level use or calibrated mic (or calibrated USB Mic

 for speaker measuring only) 

Or, to get started for free, download the Spectroid app for free.

Brief report.

Electrical Experiments using Entech Sniffer

Interesting experiment: 
1. Put noise sniffer into raw outlet usually occupied by my Audience Adept and rest of gear.
2. Positioned laptop next to meter with live zoom feed to my phone.
3. Went to nearly every single thing on the same line as that outlet and plugged and unplugged it. Watched zoom feed on from my laptop on my phone.
4. Some things had no effect on reading. Some made it noiser by 3-5 increments; some made it quieter by 3-7 increments.

Interim hypothesis: leaving those things on upstairs might make my audio background quieter. Hmmm.  But since that's not how I listen, I plugged everything back in.

Trying again, this time with everything into my strip, with the Entech in there, too. 


5. Plugged in Audience and rest of rig. Plugged sniffer into the power strip they are plugged into (which has a Venom Defender in there, too.)
6. Repeated all the pluggings and unpluggings listed above in (3.)

Result: no change made any difference at all. None.

Ultimately, my Audience Adept r2r makes a difference according to this sniffer. The Audience drops the reading by 30 points so and adding the the Venom Defender into the strip drops it another 12%.