Hey soundog ,
I've spent the last week trying to get to the bottom of this and even brought in an engineer last night.
I'm playing through a Strat with DiMarzio PAF humbuckers. They sound clean on the dry signal so I know they aren't contributing.
I am on a solid state Mac OS Mojave so no issues there.
I've ditched my Mackie mixer for my little Apogee guitar interface. I get a MUCH cleaner signal through that little thing for whatever reason. I've turned my studio upside down & inside out, still no idea how to get a better signal through my Mackie...life's too friggin' short so Apogee it is.
We've established that I do a mild ground loop issue in my set up and that a power conditioner will go a long way, so I've got a Furman coming my way hopefully tonight or tomorrow.
Still got that damn overwhelming hiss on certain hard driven presets though!!! At the same time there are some crunchy presets that are beautifully noise-free...That leads me to believe that the issue is inside the plugin.
In case you're wondering what I tried with my Mackie mixer in an effort to feed the Helix the cleanest signal possible, I've tried the following:
-Swapped out guitar cables
-Walked away from my Mac to different areas of my studio incase my guitar was picking up something
-Moved the usb cable well away from any power cables
-Ran my guitar through a D. I. box with a ground lift
-Plugged my mixer into a different power outlet on a separate circuit breaker to eliminate the possibility of a ground loop
-Plugged my entire set up into a 2-prong power adapter to lift the ground (not that I'd want to do that long term but what the hey)
-Boosted the channel fader a tad further to help strengthen the dry signal
-Ran mixer and Mac through a power conditioner to eliminate the possibility of dirty power
...Still only a small difference once I got playing the hard driven presets in Helix Native...Nothing useable if I was to record. Yes, noise reduction tools at the mix stage are always an option, but I'd rather not have to screw around like that for the amount I paid.
I cut out all the boxes in the presets and made sure levels were at unity with and without plugin. No noise - Super quiet.
As soon as I add distortion the noise starts. I've never heard distortion pedals that add this amount of lollipop to the signal in my life! The tone rocks - the noise ruins it.
Man I'm stumped...WTF...my words exactly!
Still waiting on a response from my service ticket.