He has already done some troubleshooting videos, e.g. the quad copter one, and i would think veiwers sending in stuff would be iffy... most people would send in things like cell phones and speaker amplifiers such as yourself, while dave finds unique and obscure thing with the odd commercial product to keep things interesting,
as for your speakers popping when you turn it off, its from the amplifier dumping its bulk capacitance through the speaker coil, most cheaper units, such as my own compupal speakers do it, the only easy way to modify it is to add a delayed off relay, where the contact opening on the pod rapidly turns off a relay in between the speaker output, and then a delay be it an op amp and RC time constant or otherwise to turn the amplifier off afterwards,