With more Eurorack modules added to the studio, I had a need for yet more adapter cables. Previously, I had made cables for patching between banana systems and 5U quarter-inch systems, and between banana and Eurorack mini-jacks. I now wanted cables specifically adapting Euro to 5U, and decided to build ten four-foot cables with 1/4 inch phone plugs on one end and mini-plugs on the other.
The quarter-inch phone plugs are: Switchcraft 250.
The mini plugs are: Rean/Neutrik NYS226BG.
The cable is: Canare GS-4 guitar cable.
The GS-4 cable has an extra black sheathing layer beneath the copper braid and over the insulation for the center conductor. The black sheathing is conductive! It must not be allowed to touch the center conductor.
Technique
I have made a lot of cables with shielded cable, and there are always two important considerations not to be overlooked:
- Mechanical strain relief, so that stress on the wire does not weaken the electrical connections
- The electrical connection of the shield braid to the ground sleeve on the jack
I solved both of these problems using #20 tinned copper buss wire. The buss wire is looped around trimmed shield braid and soldered to the braid and to the plug ground stem, for a perfect ground connection with added mechanical strength. This technique also has the advantage of avoiding the use of electrical tape or heat shrink. Everything remains exposed for easy repair, if needed.
When tinning the center conductor for the mini plug, do not twist before tinning, or the tinned wire may be too big for the little hole on the tip lug. Leave straight and add just a little tinning at the end to hold the strands together. Test the fit before proceeding.
It’s been pointed out that the Rean Neutrik 3.5mm plug linked to Mouser.com in this post has had design changes. Go to the link and look at the Documents section to find the design change notifications. You may want to choose a different plug.