What cord do I use to attach the amp to my computer? I am trying desperately to download the updates on this thing (it's a gift for. My boyfriend) and I have no idea what I am doing. Any help is greatly appreciated. (I am logged in under his name, but don't worry he never checks this email unless he is looking for something specific). I have the Amplifi 75 and a mac computer. I also have an iPad and an iPhone if that will help at all? Thanks so much!!