Issue Resolved!
After doing some poking and proding on the passive circuit boards that govern the speakers I found no issues. All capacitors and resistors were within tolerance, all points soldered well. I sort of gave up after that point however while I was grabbing an LP out of the cabinet my sleeve caught the top of the A-B switch and immediately cut out my right speaker. After a bit of contact cleaner and some vigorous ON-OFF's it's back and even sounding better! Gummed up contacts... GO FIGURE!