Judging by the dates of this thread, it may be too little too late but I feel compelled to make a comment. I owned the same solid state Stax combo as the poster of this thread, for about twenty years and was very satisfied until I finally bought an SRM-T1 tube driver unit with Lambda Signature phones here on Audiogon. It was a huge difference, owing to the tube driver unit, I believe. I keep thinking I'll buy some 007 or 009 phones but, at more than twice what I paid for this combo, I always hesitate to pull the trigger. I will buy one soon. But, back to your issue, you might look at some of these new orthodynamic units from HiFiMan or Audeze, they look promising and sound great!