hung bros just doesnt do the soldering.
as long the wire is conductible, even with jumper cable/clothe hanger, it can be soldered with different heads to be a stereo/mono instrument cable as well, quality sound wise, thhats another thing.
i have used the cables bought from hung bros for my diy cable with my audio interface, it works, expect that one end of it is a female stereo jack. If wanna a mono plug on the other end, just combined the 2 shielded conductor into one and solder to the tip of the plug and the ground still goes to the sleeve.
heh, on the other hand, another much easier method is prolly this. 2 mono cable into this sorta below. I bought this from sheng shiong, so dont have to go too far nor pay too much for it. This below is a 2 mono to 1 mono output. If need 2 mono to 1 stereo, it can be easily gotten from homefix or sheng shiong as well.
If really particular about using the instrument cable of choice, 2 mono cables can be easily soldered with one stereo plug on one end and 2 mono plugs on the other end, it wont look nice, but confirmed will work.
hehe, theres another method, but geetar player prolly not gonna hear "mojo" in such cable