I just acquired a used Spider V 240. It sounds great as a guitar amp. Really good. However, If I play music through it, from my iPhone or MacBook, the EQ is not good. It is lacking in the high frequencies, as if all the music is playing through the 12" speakers and not through the tweeters (But it is playing through the tweeters). Is there an EQ setting for music playback? I was hoping it was going to sound good as a music playback device, as they have advertised. I hope there is a way to fix this?