I heard this amp was great for busking. You can plug a microphone straight in without the aid of mixers or EQs. I have a dynamic Sennheiser E845 microphone and an RCF 310a amplifier. When I plug the mic in (XLR cable) the amp SEEMS to recognize the mic because there's a little green light called "signal" that turns on whenever I talk into the microphone but there's no sound coming from the amp! Why is this? I've already tried calling up Sennheiser and they just told me another number which is closed right now.