Got mine today. Installed super easy on my Win8 lappy. Sounds great from the very short time I've had with it! Only gripe is it's going to be a pain to roll the tube because they didn't use standard screws on the case.
FrankiologyIt takes time for tube/tube-hybrid amps to warm up. You might get some crackling the first 30 seconds or so, but it shouldn't go longer than that.
FrankiologyMake sure you aren't overdriving the input. You should feed it the "line out" from the audio source. If you don't have a line out to feed the line in on this amp, be sure to turn the volume down on the source until the sound is clear from this amp and then adjust the volume up/down on this amp to suit your needs.
heliosphannI keep mine at work, and the first thing I do is flip the power switch when I walk in my cubicle. By the time I'm settled it's good and warmed up. Love this DAC.