M-Audio Omni I/O - mod to use it standalone, w/o computer

I know there are some on the forum with an Omni I/O breakout box (connects to a PCI card/Delta 66), and I just wanted to share a mod I just got finished with that lets you use it independent of the computer. The basic idea is to jump the outs of the breakout box to the ins, bypassing the computer, so it can be used in stand alone mode. Special thanks to Hugh Robjohns and Will Bailey on the SOS forums for helping me to get this going.

It involves buying a male 15-pin D sub:

, that is made to be soldered, so the back side of the pin would look like this:

I attached this D-sub to the “computer end” of the breakout cable, the other end being plugged into the Omni I/O box. Then I applied signal to each of the 15 solder sockets and noted which 4 of the 15 sockets sent signal to which direct out (1-4) on the Omni I/O box. Then I sent audio into each of the Omni I/O’s four audio inputs, and saw which of the 15 D-Sub solder sockets the signal came out of.

The results are as follows, as originally suggested by Will Bailey in 2013:

1 - analog out1
2 - analog out2
9 - shared ground/shield for out1 and out2

3 - analog out3
4 - analog out4
11- shared ground/shield for out3 and out4

13- analog in1
6 - analog in2
14- shared ground/shield for in1 and in2

15- analog in3
8 - analog in4
7 - shared ground/shield for in3 and in4

It’s important to keep in mind the numbering is like this, where the SOLDER end of the pin is shown:

So, on the 15-pin connector if 1 is soldered to 13 (Analog 1 Out/In), 2 is soldered to 6 (Analog 2 Out/In), 3 is soldered to 15 (Analog 3 Out/In), and 4 is soldered to 8 (Analog 4 Out/In), you can then plop the 15-pin D-sub right on the back of the unit, and the entire analog arm of the unit is now available … without a computer!

So now, in stand alone mode, you have 2 “free” decent pre-amps, a “free” decent dual output headphone amp, and a little mini-mixer with insert points, a Mono Out/Stereo Return aux bus, 4 direct outs, etc!

Final thing I did was buy a metallized protector hub to physically protect it, and maybe do some grounding as well (bought locally):








The nice thing is, it is completely reversible - if you want to use the PCI card or the S/PDIF, just pop the D-sub pin off the back of the Omni I/O box, and connect the computer to the unit in the usual fashion using the breakout cable.

Hope this helps someone!

Can you upload a pic with the exact numbering of the pins? Thank you