This on usb cables

Just yesterday I replaced the stock cable with an AQ Carbon 3 meter to connect my 10TB external hard drive to my Cambridge 851N network player. I was mainly motivated by the need for a longer cable, but I’d been surprised in the past so I thought I’d try a (relatively mild) upgrade. Instant improvement in sound—better sound stage, better clarity, maybe a little better bass. Not night and day, but I’d do it again in a heartbeat. The Cambridge goes through a Marantz AV8802a to Bel Canto ref 500Ms to Dali Mentor 6s. Nordost and Morrow cables. So my mid-fi system detects a change USB cables, go figure.

Thanks for your opinions.  
Did not know about the lending library, sounds like a great idea.   I live in a remote location in NY so there are no shops I can go to for a listen.   
I was wondering about the usb interface coming from the intel nuc as well,  thinking the quality of that interface may prevent qualitative improvements.   
Dave

Read/understand the fine print when borrowing from the lending library at the Cable Co.  They don't let you borrow cables for nothing - usually means that you end up buying cable from them at full retail price. Research + used cables seems like a better idea to me.