I didn’t find a ton of information on this topic so I figured I would start a small guide showing my own work. The first thing is trying to find EL-8 connectors, they are only sold a handful of places. I went with Moon Audio for both the EL-8 connectors and their Blue Dragon headphone cable with quad conductors to create a balanced EL-8 cable. The last part of the cable is the Neutrik NC4MX-B that connects to the S.M.S.L. sAp-10’s balanced 4-pin out.
Here is the diagram that Moon Audio sent me a screen grab of to show how to solder the EL-8 plugs.
The above slideshow shows how I prepped the cable for soldering to the EL-8 cable. The main thing to remember when doing this is to keep your channels clearly sorted and identified, such as I did with using red/black heat shrink to easily show when soldering.
Then we have the finished product after putting the Neutrik NC4MX-B together. Keep in mind when soldering that end you must have that screw on part already down the cable from what you are working on. In the shot where I have the 4-pin soldered, that piece is pushed down the Blue Dragon cable.