I bought a tube headphone amp off Ebay from US, listed as Brand New and New in Box, I paid near half price for it. It gets delivered, it's 110v, I use the supplied cable and use an adapter, which I use for my other 110v stuff. The amp is dusty, has scratches and I pulled white pet hairs off it. Flick the switch, nothing. Check tubes, sockets look grubby, tube pins look used. I clean off the dust, re-seat the tubes. Fllick switch, nothing. Check fuse and it's blown. So I go buy a set of fuses. The amp is rated at 120v @ 0.5A, the fuse pulled is 250v 0.5A. I replace with 250v @ 0.3A = instant blow I replace with 250v @ 0.5A = instant blow I replace with 250v @ 0.8A = instant blow I replace with 250v @ 1.0A = turns on, tubes light up, a horrible buzz sound, like can hear it 2m away. Front Trafo cover is getting hot, not sure if it's a normal hot or too hot. I turn it off after 2min, i didn't plug any headphones in to hear if buzz is total. I have a mutlimeter but no idea what i'm doing. What can be done or checked to test if it either works proper or is too dangerous to use. I've lodged a complaint already, so I can't pull covers off jus yet to look for burnt PCB or Trafo. Worse case it gets sent off to doctors to get a full inspection and re-build, price dependent ofcourse.