I've lost the power cord to my Marshall JCM 900 100 watt head. On the back of the amp near where I plug the power cord in, it says "120 V 50 - 60 Hz 375 watts." It's 3 pronged going out and 3 pronged going into the wall. I'm looking to buy a replacement power cord but don't know the correct specs for the power cord. Would I be OK getting a replacement cord saying its "15 amp" ? Thanks in advance for your help!