Yes, I do have the loop set to "instrument level." Also, I don't think the level hitting the front of the amp is the problem, because I'm able to set the Helix up to go into the front of the amp just fine. It works either going in front, or after the amp. I'm just not able to do both without getting the terrible squealing and distorted sound. I'm wondering if I have a ground loop problem going on in the FX Loop, but when I push the ground loop button on the back of the Helix nothing changes. Thanks for all the help! I really appreciate it!