When it works, it sounds good. Internally, however, the quality of the workmanship is very poor, and the design is faulty to the point of being dangerous. The high voltage AC leads from the transformer are only tack-soldered to the board. When I plugged in a pair of Bose Quiet Comfort 15 headphones, the full wave bridge rectifier partially burned out and the resultant overcurrent caused one high voltage AC lead to spontaneously desolder itself and ground out to the case, blowing the fuse. Apparently, it has to have a resistive load on the headphone jack or it blows up. This is not mentioned in the documentation I received. QC15 headphones have essentially no DC impedance. The amp sees that as an open circuit, and that causes an overcurrent of sufficient magnitude to destroy its rectifier. In a couple of decades of using and repairing tube equipment, I have NEVER seen any audio tube circuit designed in a such a way that having an open on the output could cause damage. Shorts circuits, sure. Open circuits, never.
The manufacturer has disappeared from the Internet, is not answering any emails to his eBay seller account (DavidZheZhe), and has disabled new user registration and all email functionality on his website (littledot-dot-net). There is no way to contact him, there is no way to obtain support, and therefore no warranty. The product has obviously never been evaluated by UL or TUV as there is no way it could past muster from a product safety standpoint.