USB cable

@melm  I thought it should work, since it is differential signaling (receiver detects the difference between +data and -data lines.  Receiver ignores any common mode (including GND reference).  Many people lifted GND (cut GND wire) and reported improvement in sound, but it might not work if system uses Single-Ended signal for handshaking.  Easy to try with cheap plain cable.  I will read more.

USB cables made no difference in some systems and huge difference in others.  It can be attributed to the type of the DAC.  When DAC is synchronous cable can affect timing, but with asynchronous DAC timing is not involved.  Better shielding plays role, but very expensive cable doesn't have to be better - try before you buy.

You almost always will need the ground as the common mode range of the differential transceivers is rather small.

Audio2design - It makes sense.  Thank you.

There are people who lift the ground after handshaking takes place.  Others install a small resistor in the ground line.

The best USB I've heard close to this price is the Laboga Emerald.  It's not the easiest to source, and judging by the absence of mentions on this forum, probably doubly so in the States.

Of all the USB cables I trialled it's the warmest, most analog and most musical I heard.  I ended up, however, with the FTA Sinope as it's similar in character but just better.  And 3 times the price.

The Emerald deserves more exposure as it really is excellent.