I've tried all settings levels but the white noise is always evident when plugging straight into amps (tried it on three different amps!).

The only time the white noise is almost non existent is when I plug into the loop of my Mark V. I don't think that tells me there's a problem with my setup, cause I'm using two different H9's and the noise is evident in both units. I think this speaks more about the effects loop in the Mark V(it seems to take certain brilliance from the sound to engage the loop vs. hard bypass).