This is quite interesting actually.
I built 2 IC's, one with Mogami W2534 and Neutrik Profi, and one with BL-1 and Furutech FP-126.
Listening with my Senn HD650 (Creek 5350SE amp + Creek Destiny CDP) the BL-1 is very bright, even harsh sometimes.
This is odd because the Destiny is a very smooth player and the HD650 have the reputation of being rolled off the top.
At first I thought this was because of a recent recap of the CDP, but I dont have this issue with the Mogami IC.
I am reluctant to conclude that the BL-1 could have such an impact, but there is no doubt that the sound is harsh with that cable. It is very noticable (painful in the ear at moderate volumes), and that is not the case with the Mogami.
Wondering also if the Furutech RCA may be the difference here and not the cable