I have a low level hum/whine coming from my copper pipes at times. It stops when I turn off a tap. Ive tried to pinpoint noise thinking it was coming from checkvalve at the main, toilet, water softner, studor vent etc.... nothing, it just kinda everywhere if that makes sense.

Pressure from city is spot on 60 psi.

Whats likely happening here?

The most common sources are a pressure reducing valve, or a water softener, but we do not know if you have either. Heat traps in the water heater could cause it if it only happens when you use hot water.

I have a softner but I do not hear the noise in proximity to the unit. The softner is a new installation, however the whine was here prior to that with an old softener in place.

Its your Pressure regulator. It is located next to your main shut off valve for the house.

Don't have pressure regulators here. Only thing at main is a check valve...

Turn off toilets
And check again, possibly fill
Valve/s or loose washers on angle stop, or vacuum breaker on hose Bibb

Our town has used a meter yoke for many years that has a built-in check valve. About 12 years ago during a water quality issue, large amounts of different chlorine compounds were used. This caused many rubber parts to swell and fail. The check valve rubber washer became wavy and caused a loud humming noise throughout the homes anytime water was turned at any faucet or a stool was refilling, even though the meters were in a pit as much as 50 feet or more from the home, Replacing the washer stopped the noise, and it never failed again.