There are definitely only 4, so nope, no clarification.
I disconnected the transformer from the amp completely, so that the circuit (which never really turns off) couldn't be causing the imbalance. I'm at something of a loss. Unless the white wire is supposed to be on the center tap, too. I checked the diodes, remember, they were fine, too. I haven't changed anything, really so the imbalance has to still be there. I just don't know why.