How noisy is my line? Audio Prism Noise Sniffer

What the heck is woojum??

Do you mean boojum?

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.