My subwoofer plate amp from China also has the same problem and very frustrating. I wonder if the same/similar auto-standby modules are used commonly in China, ending up in multiple products. I cannot leave my sub amp in auto-standby and have to leave it "on." Does Aiyima A20 mono at leaset have manual on-off option?auto-standby function on these units is deeply flawed. The threshold is set too high, causing the amplifiers to shut down automatically during low-volume playback