Hoping someone can help. I'm using my iMac with os Yosemite, and a behringer usb interface ufo202 model to record cassette to mp3, with garage band. It is sounding great with the exception of a random scratch sound that occurs every few minutes. I tried turning off electronics in the area that might put out that signal, eliminated everything I could imagine except the usb interface. I like the ufo202 and the results except for the random intermittent noise. Can someone suggest an alternative to the Behringer ufo202?