Just got my new Hartke head and want to check it out. I don't have a speaker bottom yet and my impulsiveness is killing me. I DO have a Behringer BX600 combo and it has this neat little imput titled "power amp in". The owners manual on the BX600 says that this is " ...to feed in the output signal from an external bass amplifier." It goes on tho say: "To use the power amp of you ULTRABASS for an external amp or preamp you need ot connect the line output of the external amplifier to the POWER AMP IN jack on your BX600." Can I plug the damn Hartke head in or not???? Do I have to wait till sunday when I go to my brothers to hear the head? My local music store guy said I can only plug a preamp in, but if I plug the head in it's gonna blow. HELP! The impatient little kid in me is about 5 minutes away from possibly frying an amp.