I re-read my previous post and it requires some revision. Sorry, Mark.
BTW, I know this is a frustrating problem and finding the answer is equally frustrating, but the problem and the solution will be found!
...try swapping the L&R interconnects from your preamp to the Dodds to flip-flop the channels (in other words leave the ICs connected correctly at the preamp, but plug the left IC into the right Dodd and vice versa). If the problem switches from one speaker to the other, then you know the amp is the issue.This should read, "then you know the amp is NOT the issue, and the problem is upstream."
If the problem does not flip-flop, then restore the ICs.In this scenario, the amp IS the issue.
BTW, I know this is a frustrating problem and finding the answer is equally frustrating, but the problem and the solution will be found!

