Left/Right imbalance

[flamerz]

First off, yes I have switched sides, I have tried many sources and another person has confirmed my belief. I've searched the topic, and that should cover most of your questions. None of the OP's from the search results had checked as thoroughly as I. I've resoldered a couple times when the balance was normal, and a few times since it's become imbalanced. I've matched the left/ground and right/ground impedance on the jack and on both drivers. What's the deal? I couldn't remove all of the solder from the jack during my last couple resolder attempts, which both took place today. Some of it is on the metal part circled red in the following picture:
 

 
Does anybody have any insight? Thanks in advance.

 

[flamerz]

bump
 

 

[shadow419]

You would think that with matching impedance you wouldn't have any such issues.  I guess the only thing I could suggest is using a virgin trs plug.  It kinda sucks, but it's possible that on insertion of the plug into the jack that extra solder could be causing the Z to go up on one of the channels.