So.. I picked up a Fender Pro Junior... It's a little 15watt tube-amp.. In the store, the thing was exacrlty what you want in a 15 watt tube amp.. super clean, super loud.. sweet tone... nice and crisp.. The amp I purchased was not the same one I tested Anyway, I get it home and out of th ebox.. turn the tone and volume knobs all the way down... plug in.. turn it on.... Before I even touch the volume knobs? HISSSSSSSSSSSSSSSSSS I unplug the internal speaker and stick a 1x10 cab I have lying around.. literally.... HISSSSSSSSSSSSSSSSSSSSSSSS uhm.. Help?