I bought this pedal hoping to use it in four cable mode to get the most out of it. I use a fairly high gain Friedman-style amp set at a moderate gain level. As soon as I plugged it in there was an unacceptable amount of white noise in the signal that was not affected by either the built in noise gate or adjustable output impedance. I tried different cables, power supplies and guitars. No change. I tried plugging into the front of my amp with only the HX One in the chain, using its included power supply, and the noise was still there. The only way I got rid of the noise with the pedal plugged in was when I put it in true bypass mode with the effect off. As soon as I turned the pedal on again the noise was back, along with the effect.
I then plugged the pedal into the effect loop of the same amp and the noise was gone. Whatever was causing the noise seems to have to do with the interaction between the pedal and the preamp.
After searching for solutions to this issue online I found that many have had issues placing the HX One before certain drive pedals and some people have had issues with certain amps. This appears to be either a hardware issue or a software issue that Line 6 has chosen to ignore. None of the people that had the issue seemed to have any solutions to the issue other than not placing the HX One in that spot in the signal chain.
Since this meant that I could not use the effects that I want to have before the preamp, the utility of this pedal was pretty much cut in half for me and the pedal had to go back.
It is a real shame for such a promising concept to stumble on the finish line like that.
