I can confirm that make for DIY was great.

I used this FS: Passive SpeakerLink to RCA Adapters, thread as an example.

The Neutrik boxes are great !

I only used a different Neutrik box, which has RJ45 CAT6A on one side, and SPDIF 75 Ohm on the other one.

#1 568.2mm, HD621, G91DH, 513, 511, DSP3100 , DSP33C , DSP33, 2x MJ Pro 50 MKI, M1500
#2 G68J, HD621, DSP3100, DSP5200HC, DSP33, 3x MJ Pro 50 MKII, MS200, SB Touch, Vertex 2
#3 G61rsl, HD621, 596P, DSP7000, DSP5500HC, DSP33, 2x MJ Pro 50 MKII, M1500

Applied mods: NOS-SRx Filter by Mr. Apodizer
Mr. Apodizer Digi box