I read somewhere the helix master volume should be turned up to 10 which is essentially unity gain. When I first plugged Helix into a board, I had a lot of hiss. I had the volume about 50% and consequently, the board's gain was turned way up to get a usable signal - thus a lot of hiss. So then I turned the Helix to 100% and the board's gain way down to compensate. Hiss gone. Here's what I've noticed though, I'm running into a Mackie DL1608. When the phantom power is on, it attenuates my Helix's sound by -10 to -20 and I have to increase the gain to compensate. Turn the phantom power off, and I get a great, strong signal to the board. Apparently the Helix doesn't play well with phantom power.