Power quality, what to look for

I guess you guys will be the most talented I could find when it comes to answer questions about power/current quality and what to look for. I have the opportunity to use a quite advanced measurement equipment which is plugged into the wall outlet next to my hifi gear (with a DAC Jr and Pass Labs amps). However, the guys lending me the equipment are experts on current for trams and locomotives (!) and cannot add much to my understanding of how the figures should be interpreted for audiophile stuff. I hope that you could shed some lights on this matter and what to look for.

In short it can measure and report on (over time) frequency, voltage and transients, as well as harmonics (also individual) and THD. It measures on phase to neutral and neutral to ground. Since I live in Sweden we use 230V (which I can see is actually 239V btw…)

It would be extremely interesting to start to get some knowledge about these things - really down to the basics I think and where it all starts in a way.

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Not sure if I posted in the wrong section since I got no feedback on this, so here it is again:

I guess you guys will be the most talented I could find when it comes to answer questions about power/current quality and what to look for. I have the opportunity to use a quite advanced measurement equipment which is plugged into the wall outlet next to my hifi gear (with a DAC Jr and Pass Labs amps). However, the guys lending me the equipment are experts on current for trams and locomotives (!) and cannot add much to my understanding of how the figures should be interpreted for audiophile stuff. I hope that you could shed some lights on this matter and what to look for.

In short it can measure and report on (over time) frequency, voltage and transients, as well as harmonics (also individual) and THD. It measures on phase to neutral and neutral to ground. Since I live in Sweden we use 230V (which I can see is actually 239V btw…)

It would be extremely interesting to start to get some knowledge about these things - really down to the basics I think and where it all starts in a way. What matters and what doesn’t? As a starting point for investing in PS power cleaning gear, it would be interesting to understand the current (!) status. :slight_smile:

I suspect the purpose of your post is getting “lost in translation”.

You might want to try again by asking a specific question or making a succinct statement.

Otherwise, I am afraid you might not receive much in the way of response.

Respectfully yours.

I’ll try to give you some basics to narrow down the details. I worked for an electric utility for 33 years and I have a PS Audio Power Plant. I bought the Power Plant because my oscilloscope showed that the sine wave was flat topped and mis-shaped, and the Power Plant tells me that the utility supplied voltage Total Harmonic Distortion (THD) is about 5%. The Power Plant output is at about .1% and it makes a huge difference with my audio and video enjoyment.

First - frequency is not much of a concern for high end audio, as long as you use equipment rated for the local AC line frequency.

Second - the line voltage always fluctuates in response to energy consumption at your point in the electric system. Electric utilities are compelled to keep the voltage within a specific range so 239 volts is probably within the range. Likely it will change by a few volts at different times of the day, yet it will not be totally predictable. On the Web, check your local utilities standards for voltage, and measure it for a period of time. Years ago I was suspicious that the outside utility transformer was too small for the number of homes connected, so I did some measuring and saw that the voltage sagged far too low. I called the utility and they agreed the transformer had to be replaced. Yet, the more normal voltage fluctuations are often too much for high end audio and video.

Third - the incoming voltage THD measurement is very important, and viewing the sine wave shape can confirm what is being measured. Again, utilities are to meet a standard for power quality, however good “power quality” is more than just low voltage THD. If you find the THD is actually reasonable (such as less than 1%) a power plant can still improve audio/video performance as mentioned in PS Audio marketing information, such as reducing ground loops, electronic noise, etc.

I hope this helps.

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Some good information about power quality— worth reading

https://www.passlabs.com/press/power-supplies-commentary-consumers

Thanks @MarADyr, that was really very valuable info, especially about the importance of (a low) THD. I have around 2% so understanding that it could go as low as 0.1 with a Powerplant is really worth considering.

Yes, that’s a good article. I have seen it a while ago (since I have a couple of XA100.5:s) but it was fun reading it now again with the perspective of power quality in general.

One conclusion could be that it is almost impossible to know (without A/B listening tests) to what extent for example the Pass Labs blocks succeed with cleaning the AC power as described in the article.