I just had the same problem with my Spider IV 75....no sound from the guitar, however the cd/mp3 input has sound through the speaker & headphones. I tried the factory reset...no luck. When I hooked up to the Spider Edit software and reloaded my saved settings, the amp now works! Only time will tell for how long. Psarkissian, do you have an explaination as to why after reloading the saved settings that the amp would start working again? Perhaps my experience will benefit someone else. As I use my Spider IV to play along with backing tracks, if it is a momentary fix I should know soon. I love the amp, and will be sad when it breathes it's last note.
