The power (voltage) fluctuates greatly, 108.1 - 134.2, and is constantly going up and down rapidly as proven by a meter that I hook up before the power conditioner. The voltage still goes up and down if the meter is plugged in after the conditioner, but the conditioner makes a huge difference in the amount of hiss. I use a simple Furman PL and the difference in hiss with or without the unit is extremely noticeable, way beyond even considering not using a conditioner. The P.A. had so much hiss without the power conditioner, we turned it off between sets, but the hiss was completely eliminated with a conditioner and you can not tell if the P.A. on. My bassist, after seeing the voltage jumping around and hearing the difference with just the conditioner, has ordered a voltage regulator to go with the conditioner.