Simple MIDI in cable

How to make a SUPER simple MIDI cable to send data to your joystick / MIDI port.

I had a M-Audio USB uno, which worked great on my ghetto keyboard, but on my newer setup, it would constantly dump garbage notes. Rather than go spend yet another wad of hard earned money, I realized that I probably had most of the parts at my house already.

Step 1: Do Your Homework

After googling around for a bit, I came across a few basic schematics. This one was the schematic I was planning on following, but I had to deviate slightly.

My local Fry’s Electronics didn’t carry a 6N138, but they had the NTE equivalent which I found was a NTE3093. I had resistors at home, but I found I was out of 220 ohm, so I went with 270 ohm, which appear to work just as well.

I didn’t care about sending MIDI signals out of my PC, so I left that part out of my design. I wanted all the parts to fit within a DB15 casing.


Step 2: Make It REALLY Small

After verifying that the schematic did in fact work, it was time to start stacking the parts on top of each other. With only 4 components, this was going to be easy. Building projects using this method can be a great space saver, but will make it HELL trying to repair or debug something, so be sure that everything is working as it should first.

To make this go a little easier, I broke off the 3 extra pins from the IC.

Step 3: Hope That Things Still Fit.

Now that all the parts are in a nice little ball, I put some heat shrink over them to protect and insulate them. Since it fits in the DB15 hood with no issue, I do what I do with most of my projects, fill them with hot glue. The glue keeps parts from shaking around, breaking or falling out. Plus, it gives the plug a satisfying weight.

I inject the plug half with glue then smash down the top piece, cutting off the excess with a razor. Then tape around it tightly, and give it 15 minutes to cool down.

I now have a nice MIDI in converter cable with all the parts self contained in the cable. It works much better than my M-Audio USB uno. Hooray for old technology.

This write up was also posted to Instructibles: