I cannot believe that the plug is the cause of the brightness and lack of bass, or any other sonic differences apart from microphonics coming from wiggling the plug. Also, i'ts only the outside that is plated, the rest of the plug is "ordinary" metal. Amping and lack of burn-in sound more likely.
It could also be your ears/gray mass that need to adjust to a "new" sound.
Possibly, going to listen to them for the next few hours, but honestly, I think a more powerful amp might do these more justice (the SR-71A still does a blinding job with every other headphone and IEM I own). I can't wait for the Continental to arrive. Yes it's still a portable, but I've heard it packs a much greater punch than most portables, including the Rx MkII.
Edited by Naim.F.C - 8/10/11 at 7:43pm