This is a unit that does the job, my studio is quieter now.
BUT, the noise I lost in audio, I gained in mechanical hum from the toroidal transformer inside this unit.
Its humming a bit, not much, but I can hear it if I turn off everything else.
Remember, it is a mechanical hum from the transformer vibrating inside the unit. (not much, but a little annoying)
The audible hum from my monitors I had before installing this unit is dead silent.