Blackberry Jack
Head-Fier
I use the ibasso CB13 cable, but I believe that any silverplated occ cable of around 50-100$ will do the job. Although cables really make a difference, I dont think its reasonable to spend more than 100$ on it for some middle-priced IEM.I'm thinking of trying a new cable with my N40s. Given how much of a difference it made to my BGVP DM6 IEMs, it's worth giving it a go. Do you have details of the cable you bought? I could try my aftermarket cable that I bought for the DM6 as a start.
And dont forget to check the Final Audio eartips, they are really nice - made the bass punchier and took the mids slightly more forward - which made the vocals and some instruments shine.