The RCA connectors are Neutrik spring-loaded NF2C Profi connectors, and the person who built them used silver wire to connect them to the XLR connectors and silver solder, and they have floating ground wires that connect to the ground lug on the back of each Dos Locos. I’m told they sound better than stock Neutrik XLR/RCA connectors.
@superkat The correct way to wire a balanced line phono input is the shields of the left and right channel are tied to pin 1 of the XLRs. There is no need for the ground wire; if there is one you can assume its wired incorrectly.
I've been running a balanced input for the phono section in my system since 1989.
If you are coming from RCA connections on the turntable, the ground post is tied to the shields of the interconnect, and so become pin 1 on the XLRs. The shield must not come in contact with the 'ground' connection of the RCA. The RCAs are tied to the + and - outputs of the cartridge so you can see why this is so.
If the cable is built correctly you'll find it to be quite neutral even if the cable is inexpensive (it must be low capacitance BTW). The reason to run balanced line is to eliminate interconnect cable colorations; if there is any place this really has to be right its the input to the phono section!

