bassbikemike

Thanks @codamedia and @Kilrahi. This is the first Helix product I've had so I'm really just still getting to grips with it... I actually tried using the Aux In 1/4" jack before I posted (just trying to get a mono signal out of the L channel to get started) but didn't get any audio through into my IEMs... Your responses made me go back and have another go. After some changes in Global Settings (Ins/Outs page) making sure that "Send/Return L" and "Send/Return R" = Line level and "Return Type" = Aux In (this was set to Return before), I now have it working correctly, so I'm made up. Now to get a Y lead 3.5mm stereo to 1/4" mono, like the one @Kilrahi linked to above. Even better that you can stream digital signal eg a Youtube clip into the Stomp and have that coming into the mix on the IEMs too! Thanks guys.

My only disappointment with the HX Stomp is that the inputs are only switchable - unless someone can tell me I'm wrong. My old Boss ME50 (which was inferior in EVERY other way) allowed me to Line IN an mp3 player on the 3.5mm jack and mix that with my bass signal so I could practice playing along with stuff on IEMs. The HX Stomp can't seem to do that though.