Signal Processors

This dual-channel compressor combines valve circuitry with an opto-compressor design. But does it deliver the best or the worst of both worlds?

I record guitar using a Line 6 Pod Pro going into a Roland VMC7200 mixing desk via S/PDIF. While the guitar is plugged in, every so often a little audio spike comes through the monitors. Can you tell me what this noise could be and how to stop it?