Received my DX1 yesterday, I quite like the cable and there seems to be nothing wrong with mine. I like the generous length, and also the cable itself - it's sleek and modern, I have never seen a USB type B cable like this. Every single type B I have, including those bought last year and received with various equipment, looks like it's from a 1999 printer.
I have to say, my first impression of a Topping product is extremely positive. The device is sturdier and heavier than I expected, and the packaging is superb to say the least. Love the silicone RCA caps, wish I have enough of these for all the unused interfaces on all my equipment.
The aluminium case is super thick - I bet it will survive a tank running over it.
As for the sound, it's plenty powerful with my low impedance headphones (Hifiman HE-400 and Truthear Zero IEM). The difference between low and high gain is very significant, which is great.
I have felt the effect of low output impedance compared to other two sound interfaces that I have with me (both of which are bad). Other than that, I could find no difference even compared to objectively much worse devices. Which is not to say DX1 sounds bad in any way - only that hearing any difference between two DACs is extremely difficult. I'm glad I didn't go for a more expensive device like DX3 Pro+.