My signal chain in the rehearsal room is: Guitar -> Line6 G30 -> Line6 HelixLT -> XR18 mixer -> AUX OUT to NUX transmitter -> NUX receiver to my KZ ZS12ProX IEM. If I connect the IEM to my Helix directly it works perfectly (meaning w/out the NUX), but with the NUX it's just terribly noisy. I tried on very low volume, where it's kinda ok-ish, but at that volume it's not usable. As soon as it gets to the level where you can really hear yourself on a gig, it becomes unusably noisy.