Distortion on the Power Line

Is that a consistent 7%, or high during the day and drops at night?  If it's drops at night it is likely Air Con, but even then that is a fair amount of THD. As it is incoming I assume the PS unit is measuring voltage THD.


It's pretty easy to determine if the issue is any part of the circuit from your PS unit all the way back to the transformer. Turn off all the breakers in your house except the one to your PS unit(s), and turn off the equipment connected to the PS. If the distortion is still high, then it's a local line issue not your feed. You could alternately just turn off all the loads in your house but the breakers are probably fastest. Without any loads, any corrosion, etc. will not impact THD.

heaudio123"Turn off all the breakers in your house except the one to your PS unit(s), and turn off the equipment connected to the PS. If the distortion is still high, then it’s a local line issue not your feed. You could alternately just turn off all the loads in your house but the breakers are probably fastest. Without any loads, any corrosion, etc. will not impact THD."

This is completely false, erroneous, and even "Dunning Kruger" in nature regarding it’s ignorance and abject failure to understand even the most basic element of the problem described hear. The PS Audio device itself presents a load to the circuit so any defect in that circuit wiring as has been described as a potential by other contributors to this thread such as bad connections could produce the result described by the OP. Dunning Kruger sails again.

Please ignore my troll. I have triggered him and he posts nonsense after many of my posts.


The static load of your PS audio unit is pretty small when it is not supplying power to anything else. That static load will not impact the THD. 


I am sorry that people like that have to ruin it for others. Feel free to PM me. 

Nurse! Thorazine! Aisle 6. Man down!

You’ve gotten some good answers here, but the distortion problem you’re having could just be the very nature of the electrical distribution system itself. The electrical grid in the US is a very dynamic system. Utilities are routinely seeking to balance loads and efficiently deliver power, and some electric utilities are also under state-mandated reliability improvement programs. So the circuit you are on today may not be the circuit you are on tomorrow. Even your supplying substation may change over time.

That businesses and factories have reduced operations or even closed entirely must have had a huge impact on electric demand and use. At the same time, residential electric use must be on the increase as so many people are confined to their homes, and often working from there, too. All of those factors combined make it likely that your electric utility has made changes to its distribution system. Whether that’s the cause of your distortion is a separate question. It might be a good idea to take the suggestions of @jea48, which might help narrow down the root cause of the distortion and is good advice in any event.