hi y'all, i have a fender pa 100 tube head. it is rated at 100 watts at 4 ohms. it has two speaker outputs, each labeled 8 ohms. i have used one and two 8 ohm cabs with this amp with no issues. question: how would i hook up a single 4 ohm cab to this head? should i use a parallel speaker cable? should i have the amp rewired for a 4 ohm speaker output (if the transformer permits)? or am i missing something obviously simple?