I have a Yahama powered mixer (emx-5000 20 channel) and was wondering if I would harm the console by not plugging in P.A speakers to it.

The scenario is, I have no mic preamp to record with and no money to buy one with and was hoping to use the powered desk to act as a preamp. Obviously I don't want everything screaming out of the speakers for noise sake and would run the signal from the desk straight into my multi-track. Would this be damaging to my EMX 5000?