Question

Thanks so much for your response, and I apologize for my inadvertent ambiguity - I don't know where the 'and out' came from, and I understand your confusion. It only goes to Main L/R of the headphone amp, and  I have edited my post for clarity, and also I have a pic here that basically shows the config.

I actually also have the exact cans you're referring to, and they sound the same as well. very confusing. Any additional thoughts would be very welcome, and again, apologies for the confusion.

Answer 1

Your pic has a place marker but no pic appears. I looked at the configs in the ART manual and it looks straight-forward enough. I re-read your original post and that addresses my concerns about grounds, ground loops, etc. Maybe it's time to try a different headphone amp.

Answer 2

Yep, @johnellard you were absolutely right - just received my HPamp back after a lengthy RMA, and it was repaired. It was a broken ground on the input PCB that caused the issue.

Thanks again!

Answer 3

You're welcome, Michael, and I'm glad you got your issue resolved.