The build quality feels good but the device itself is on a bad spot overall. The case is metallic and doesn't feel cold to the touch nor it grabs fingerprints, it has an optical input which is nice. It uses a thick USB cable instead of a microusb; what happens then is that the bulky cable is too rigid and tends to lift the case on your desk. ~15 years ago the TDA1305T was used in high end audio, nowadays is a very cheap DAC with some limitations even if still very good. Compared to my T440s's DAC. It improves sound but the change is not significant enough to be really noticeable overall. The sound flavour is still interesting as I own a Fulla2 DAC/amp and I am inclined towards neutrals, though. The amp works very well and the (cheap) knob gets the job done. It feels precise. There are similar or better quality DACs on smaller formats like the SA9023A (usb stick) about the same price and truly portable. Or the Fulla with an outstanding DAC and build quality and same size.
Build quality is really good, the case feels nice and sturdy and the knob feels nice to turn. In my case, the dac makes my headphones a lot more focused towards the high end and treble, while removing a lot of bass/low end/lower mid. Not quite what I was looking for, but if you have bassier/warmer headphones, it might make them lean more towards neutral. Still, does what it advertises and build quality is good, so 5 stars.