First a bit of background: I use my amp/dac exclusively at my computer. No portable use (I have a portable amp for that). Until recently, I had a FiiO E17/E09K combo that worked well, despite its age. I bought the E17 used from the marketplace here and have used it for a number of years. A while back it simply stopped working. Wouldn't turn on, wouldn't charge. It was WELL beyond the warranty period, and I was at least the second owner anyway. I figured the battery inside had died, so I disconnected it. In doing so, the E17 started working again when either plugged in via USB or into the E09Ks dock. Weird, but ok. Last week we had a power outage at my house. It only lasted a couple of minutes, but it seems that was enough. The E17 will not turn on in the dock anymore...except that's not strictly true, and here's where the weirdness comes in... If I plug it into my computer via USB, it turns on. If I remove the power cord from the E09K it also works, but if I plug in the power cord it shuts off. I need the power cord for the amp to function, so although odd, that won't really work for me. So...unless someone has an idea here, I need a replacement. Probably won't buy it until the end of July or so due to vacation time coming up. Budget isn't that high, and it doesn't get used all the time; but I work from home so when I want to listen to music (or focus when my kids are making noise due to them being on summer break), I need something that works. None of my headphones are all that demanding, so I was initially thinking Schiit Fulla/M+M stack or a JDSLabs O2+ODAC, but I'm open to other suggestions. USB is a must, good quality is also desired as is something that can sit on a shelf, turned on, for long periods of time (in case I don't turn it off, which I usually don't). Never used tubes, but I also don't know how they would do being turned on for days/weeks/months at a time. Open to suggestions, though.