Distortion on the Power Line


I have a couple of PS Audio Power Plants.
The distortion off the wall has typically been 3.5 to  4.0.  For the last week it has been over 7%.  I checked around the house and can see no changes.  Anyone have any ideas what it is?  Have Russian Hackers moved in next door?  People huddling at home on their computers?

sm2727
Post removed 
Commercial air conditioning systems with variable speed motors are the most likely culprits.  They share the harmonic distortion with all their power grid neighbors.
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.