I am looking to dig into the electrical aspects of my listening room such as the the supply wiring from the house panel to and including the receptacles in the room to see if there is room to cleanup any potentially dirty AC. I do not have any equipment beyond a traditional multi-meter, so I was curious about purchasing or renting a clamp on power quality meter such as the Amprobe ACD-41PQ which has the capability to provide THD readings on a line.
I figure I can measure the THD on the AC line into my listening room and then decide if I need to or want to take steps to improve the AC. Does anyone have any thoughts on my proposed process? Thoughts about the qulity and reliability of a clamp on unit like the ACD-41PQ to provide THD measurements? Is there a better way to go about determining the THD on my AC line?
I figure I can measure the THD on the AC line into my listening room and then decide if I need to or want to take steps to improve the AC. Does anyone have any thoughts on my proposed process? Thoughts about the qulity and reliability of a clamp on unit like the ACD-41PQ to provide THD measurements? Is there a better way to go about determining the THD on my AC line?
Are you sure that THD on the AC line potentially (hahahaha!) is a problem? Seriously, pretty much every device you add to the mains circuits that rectifies the AC into DC will create harmonic currents on the AC mains.
Now, higher frequency signals outside the audio band can and often will cause problems. You might to investigate Henry Ott's books on that subject. I think a careful web search will find some excerpts from most of his books.
A bigger problem usually is the common mode current paths that will exist between all the devices used in your audio system that are also connected to the AC power. Here is a good tutorial on that subject:
https://www.jensen-transformers.com/wp-content/uploads/2014/08/generic-seminar.pdf
Generally, people think only in terms of ground loops and hum, but there's loads of high frequency junk that goes way beyond the audio frequency range that will affect your system performance. How about all those electronic gadgets including your audio gear? If they are capable of putting junk into the system, they probably also can be affected by junk in that same system.
In order to measure those, you'll need something beyond the usual clamp-on current meter. You'll need a clamp-on current probe that works in conjunction with an oscilloscope or a spectrum analyzer. It probably should work to at least 10 MHz or so. That used to be a really expensive proposition, but you can make your own current probes now for pretty cheap or purchase something like a LittleBee-B1. There's a couple ways to do the oscilloscope/spectrum analyzer part and they're not really expensive either. They won't give the same level of traceability as you'd get by hiring a compliance lab who might make house calls. But since we don't really know what the pass-fail criteria is for home audio systems, that probably doesn't matter at all. You just want to know if you have big issues, little issues, or no issues, and when you improve your situation by making a change.
I'm not trying to discourage you - you have a good idea. But, the problem has more layers than it first might appear to have.
Now, higher frequency signals outside the audio band can and often will cause problems. You might to investigate Henry Ott's books on that subject. I think a careful web search will find some excerpts from most of his books.
A bigger problem usually is the common mode current paths that will exist between all the devices used in your audio system that are also connected to the AC power. Here is a good tutorial on that subject:
https://www.jensen-transformers.com/wp-content/uploads/2014/08/generic-seminar.pdf
Generally, people think only in terms of ground loops and hum, but there's loads of high frequency junk that goes way beyond the audio frequency range that will affect your system performance. How about all those electronic gadgets including your audio gear? If they are capable of putting junk into the system, they probably also can be affected by junk in that same system.
In order to measure those, you'll need something beyond the usual clamp-on current meter. You'll need a clamp-on current probe that works in conjunction with an oscilloscope or a spectrum analyzer. It probably should work to at least 10 MHz or so. That used to be a really expensive proposition, but you can make your own current probes now for pretty cheap or purchase something like a LittleBee-B1. There's a couple ways to do the oscilloscope/spectrum analyzer part and they're not really expensive either. They won't give the same level of traceability as you'd get by hiring a compliance lab who might make house calls. But since we don't really know what the pass-fail criteria is for home audio systems, that probably doesn't matter at all. You just want to know if you have big issues, little issues, or no issues, and when you improve your situation by making a change.
I'm not trying to discourage you - you have a good idea. But, the problem has more layers than it first might appear to have.
Do you really have a noise problem?
Use shielded cases and proper earthing.
Read up, and unless you have seriously bad wiring, or "golden ears", you are being OCD.
Those problems are textbook problems from the 1950s and later.
We had a poster from Italy who designed a temperature control system for the granite base plate of his turntable.
Granite has a very low coefficient of thermal expansion, it is used in measurement labs for surface plates and so on.
So he was wasting his time.
But it satisfied some deep need in his mind...
Go ahead, and share your experiences.
Use shielded cases and proper earthing.
Read up, and unless you have seriously bad wiring, or "golden ears", you are being OCD.
Those problems are textbook problems from the 1950s and later.
We had a poster from Italy who designed a temperature control system for the granite base plate of his turntable.
Granite has a very low coefficient of thermal expansion, it is used in measurement labs for surface plates and so on.
So he was wasting his time.
But it satisfied some deep need in his mind...
Go ahead, and share your experiences.