recnnected the Rotel and started switching cables around. I think the issue is in with the Arcam receiver on CD setting connecting to the left speaker. (Turntable setting doesn’t have this problem). Does that seem plausible?
Entirely plausible and sounds fairly likely given what you’ve said. Also, Arcam does not exactly have a sparkling reputation for reliability, so there’s that. Maybe it’s time to start thinking about upgrading the Arcam if that’s really the source of the problem.