Hi! I have been trying to record some guitar tracks to get mixed elsewhere, but I am having a problem. I plug my guitar to my presonus firestudio mobile, and I get this helicopter-like sound that doesn't go away, regardless of if I'm playing the guitar or not. What I mean by "helicopter" sound is it's a repeating "puh-puh-puh-puh-puh" akin to the sound helicopter blades make. It's driving me nuts as it affects my guitar recording. I have substituted cables and it DID work once before, but now all of the cables still result in the "puh-puh-puh" sound. Do you think it's a CABLE issue? Or an issue with my presonus firestudio mobile interface???