According to those who write the specifications, there IS more to it:

http://www.midi.org/techspecs/electrispec.php

Note the date on the diagram. The specific opto-isolator components mentioned may or may not be available, so you might need or want to substitute a more modern replacement.

If you only need MIDI out from a sound card, there might be some shortcuts but it is always sound card specific.

Some sound cards have pretty good buffering on the MIDI TXD pin, so basically you would only need two 220 ohm resistors there.

But for some sound cards that have only weak logic level output, it may not work, and would require logic chips or transistors to do the buffering. And if the output comes directly from sensitive sound card chip, there is a risk you'll blow the pin by connecting two devices with voltage difference (both or the other is not grounded before connecting), albeit MIDI interface should be electrically isolated at the MIDI input connector.

If you want to build this kind of cable yourself, I recommend stuffing the components inside the DA-15 connector plastic case. (Joystick connectors are size A connectors, not size B)

I am no authority for answering badmojo's question, but the topic hits right on one of my own.

How well does such a converter that includes joystick-passthrough work? My research has been inconclusive as to whether or not there would be conflicts or just some input/output cut off if I try the setup I have in mind. I wonder, would it be possible to, say, use the Thrustmaster PFCS plus WCS Mark II plus RCS, and with a passthrough still get MIDI from the SC-55 so there could be HOTAS plus General MIDI in US Navy Fighters?

You just need a cable that passes all joystick pins through. Some adapters might not, if they are built to split the single joyport for two separate joysticks, each with 2 axes and 2 buttons.

badmojo wrote:

I have one of these 'Joyport (DB-15) to MIDI' cables I bought from the interwebs (something like this) but it's pretty crappy, it has a passthrough for a joystick which doesn't work (and I don't want) and it's way too long, I just want a simple male DB-15 -> female MIDI DIN plug, the shorter the better.

Hmm? I have the same thing I use on my 486, and the joystick pass through works just fine.

Jepael wrote:

You just need a cable that passes all joystick pins through. Some adapters might not, if they are built to split the single joyport for two separate joysticks, each with 2 axes and 2 buttons.

Since the HOTAS setup only requires the single port, it sounds like that would not be a problem in the case of a MIDI adapter for the gameport which only has the passthrough so a joystick can still be used. However, the Thrustmaster setup utilizes all 4 axes, so am I still off?

Let's continue this thread...

How know that the soundcard has "a good buffering on the MIDI TXD pin" ?
I have these soundcards:
SB16 ct2900, SB16 ct4180, SB32 ct3600, SB128 ct4180, GUS MAX 1.8, Yamaha YMF719e-s

I thinking about making my own cable, since I can't seem to find any these kind of MIDI cables here in Finland.

So if I took DB15 from some joystick/pad, DIN5 from some AT keyboard and two 220R resistors, then make cable using below's link schematic, which is correct? Will it work, if soundcard has a good buffering?

https://www.google.fi/search?q=joystick+midi+ … JYs7yjEAx_XM%3A

here is a simplified schematic of a working adapter for 1x Midi-OUT, I have successfully used it with SB16s:

source: http://www.cryogenius.com/hardware/sbmidi/

The inverter parts are super easy to get hold of and dirt cheap. I built this thing for free based on this circuit (figure 2) using an old DB15->RJ45 ethernet adapter, two resistors, and a 7406N chip (inverter IC) & DIN jack harvested from a dead C64 motherboard.

Note the "incorrect" DIN-7 jack, from the C64. Accepts a DIN-5 plug fine though. MIDI-OUT only but adding MIDI-IN to this would be pretty simple.

Edit: here's some helpful explanation of the circuit I used on another forum.

^ nice !
I managed to fit everything inside a DB15 shell , pretty easy if you cut the 74xx IC legs

I have a regular game to MIDI / game cable and it works fine. Just bad luck in your case I guess.

It's also worth noting that the MIDI electrical specification was apparently updated shortly after this thread started. The URL I linked to now points to a new specification that accommodates the transition from 5 to 3.3 volt signalling:

http://www.midi.org/techspecs/ca33.pdf

So I connect this MIDI OUT(picture) to MIDImodule's MIDI IN port to get game music? (Like https://www.youtube.com/watch?v=YOCHWFdvfnw 2.06 ?)

keropi wrote:

here is a simplified schematic of a working adapter for 1x Midi-OUT, I have successfully used it with SB16s: […]
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here is a simplified schematic of a working adapter for 1x Midi-OUT, I have successfully used it with SB16s:

source: http://www.cryogenius.com/hardware/sbmidi/

Yeap, just add a capacitor to filter the power input of the 74LS00 and avoid those floating inputs.

Take a look at my self made adapter with a passthrough DB-15 connector:


Mine also has an optocoupler for a MIDI input, and I added a second (empty and visible in the images) 6-pin header for the MIDI-In DIN cable (the MIDI-Out is plugged on the first header). I did not bother making a cable for that, since I'm not going to use the MIDI-In right now, but all I have to do is make a cable, make another opening on the case and plug things in.

Finaly I got those midimodules & now I am about to make the cable, but just to be sure, in that keropi's schematic, those game port 15 pin mini db & midi out (din5), are both male versions & viewed from solderable side(inside)?

Capacitor to 74LS00, between 14 & 7? What size would be good? I have plenty caps from 1uf to 2200uf, 6.3V...50V.

JackH wrote:

Finaly I got those midimodules & now I am about to make the cable, but just to be sure, in that keropi's schematic, those game port 15 pin mini db & midi out (din5), are both male versions & viewed from solderable side(inside)?

Capacitor to 74LS00, between 14 & 7? What size would be good? I have plenty caps from 1uf to 2200uf, 6.3V...50V.

If you have the connectors, take a close look and you will see small numbers next to the pins on either solder or the other side. Maybe not all pins are marked, but at least pin 1 usually is. This way you can be certain which pin is which.

Yes, capacitor between 74LS00 pins 14 and 7, 100nF ceramic is fairly typical here (rated to withstand more than 5 volts of course). It sounds like your 1-2200 uF capacitors are electrolytic and while in general a 4.7 or 10 uF bulk storage capacitor does no harm here, they are not so good here at high frequencies, so the 100nF ceramic is better.

Has anyone identified a good salvage source for an appropriate high speed opto-isolator to use in place of the Quad NAND being used as a buffer?

I don't see the advantage of using an opto-isolator on the MIDI-Out port, and I used a simple 6N138 on my MIDI In, but I'm yet to test it.
MIDI UART isn't exactly high speed.

Advantage is fully isolated ground.