I just got my HX Effects about two weeks ago and this is my first multi effects. My plan was to use this on a small fly board. I've got my Dunlop Crybaby followed by a Xotic EP Booster in de front. I wanted to use a fuzz (and maybe an overdrive) in the loop, so I'm able to turn it on and off with the HX and place certain effects (like a phaser) in front of it in the chain.
Sadly, this doesn't seem to work as I intended to, and I'm wondering if I've got a faulty unit. When I put a fuzz in the loop set to instrument level, I got noise, loud squealing and feedback. When I set it to line level only the noise it's left, but it's so loud that it makes it unusable. It's only workable when I put in in the front, after the EP Booster.
Without the HX Effects there are no problems or noise with the fuzz. In this case I'm trying it with the Mythos Golden Fleece, but I get the exact same issues with the DOD Carcosa. I've tried different power, guitars, amps and everything else as well. I recorded the different setups so you can hear the issue:
Ofcourse I also filed a ticket with Line 6 about this, as well as emailing the store from where I bought it. But maybe someone here can chime in on this. I decided to keep the HX Effects after trying it without using external pedals, but these issues are a dealbreaker for me currently, so I'm pretty bummed out.