My THX AAA 789 when I plug in a 4 pin XLR to RCA adapter to go into my electrostatic headphones energizer (I know unneeded and unnecessary considering the energizer operates as a perfectly decent amp itself designed to run the headphones) the 789 starts cutting out switching from orange to white back to orange. This however doesn't happen on the Cavalli tube hybrid amp that I own when I used the adapter on that amp (yes I know this amp isn't balanced so that technically makes a difference). I bought the 4 pin XLR adapter because I wanted to see how my electrostatics sounded on while also connected to my other amps and see if I liked the sound any more, not necessary but I like sound what can I say. Currently I do not own any balanced headphones to test if the 789 works properly on those but I wanted to know the communities thoughts on whether the issue is with the adapter I used which works perfectly on my hybrid amp, or if it is the fact that it's a unbalanced connection on a balanced port, or if the issue is the amp itself which I would then exchange for a new one if that was the issue. Honestly if it's either of the first two issues I'm not concerned at all because I really only wanted to hear my electrostatics on my tube amp anyway cause it colors the sound. The only issue I have is that I will be picking up a pair of balanced headphones in the near future and I don't want to be running into an issue where the amp doesn't work with those.