You'd have to ground it elsewhere as the K7 doesnt have a ground connection on it. Suspect a phono pre amp would come with one.
I'm using K7 with an LP5X and Amiron Home cans, its a bit quiet with the LP5X's built in amp so I've had to purchase a separate phono pre amp (Gone for a Schiit Mani 2). Hoping the gain is sufficient, its not arrived yet.
Not the fault of the K7, thats plenty loud enough.
Also to add, had mine since early Febuary and no issues with sound drops on either USB or line in, 6mm or 4.4 balanced. FWIW I didn't even install drivers, in fact windows doesnt even recognise the K7 yet works absolutely fine.
The light doesnt bother me, the volume delay is a minor irritation which I dont even notice now.
I'm pleased with the K7. I think its a bargain that will suit and exceed the needs of most people looking at a dac/amp in this price range and function, for me its attached to my PC and having the benefit of an easily switchable input to use with a turntable. It replaced my Xonar STX sound card (Which I still think is superb...)
That said I try keep a lid on the whole 'audiophile' thing else you end up splitting hairs with everything. £1000's spent for almost nothing in return. (a personality defect I'm sure affects us all on here, perhaps an engineering mindset that causes myself to look at the finer details of everything be it washing a car or listening to music).