I just saw the picture of the underside and circuitry, and it looks to have a shared/common ground. I thought Class D/T amps didn't have a shared ground? When I was messing with the HE-500 with speaker amps, one of the limitations on using a speaker tap to TRS adapter was the requirement of a common ground, and all of the sub $100 class D/T speaker amps on the market had separate grounding and would go up in smoke if connected with a TRS adapter. And to get a balanced cable generally defeated the goal of a cheap speaker amp solution (to keep it economical). The king of affordable speaker amps for headphones ended being the Emotiva MiniX which is an AB amp and has a common ground, but is also $220. It's nice to see a potential new solution to the affordable speaker amp for headphones quandary.