OP, you aren't alone in hearing this undesirable noise, and the noise has regularly been referred to as 'squirrels' on The Gear Page. In the early days of having Helix I heard and disliked the noise too. With the current updates, though, the sounds seem much better and I suspect there has been some tweaking going on behind the scenes, plus it takes a while to become familiar with what each of the less familiar amp controls and various eq cuts can achieve. My Helix has never sounded better and I wouldn't want to be without it now. Update 2.20 is just around the corner as well. I guess what I'm saying is I wouldn't be too hasty to write off the Helix and, as you got it second hand, be sure it is running the latest firmware before making a final judgment. Good luck - I hope you get it sounding to your taste.