Audio IO 1U Help

I have an Audio I/O 1u module that I’ve used many times with my 7u cases and it’s worked great. I recently got the 1U stereo out module to use in the 7u to save space and have shifted the Audio I/O to my 4u case. I’ve paired it with the Audio I/O 1u jacks of course. But upon powering it on, the LED level indicators have me worried.

Nothing is plugged into any jack. The Line In attenuator knobs are at minimum but all LEDs on the Line In side are lit, both green and red. They all stay lit at all positions of the knobs. On the Line Out side, with the line out knobs at noon the green LEDs are lit. Again, nothing is plugged into any jack. When I turn the line out knobs down, the red LEDs light up at about 10 o’clock and stay lit all the way down to minimum.

I’ve tried reversing the ribbon cable, thinking maybe the polarities were reversed or something. No change in behavior. I’m at a loss. I’m also worried to actually connect anything to the output to test it, if it is blasting out maximum voltage levels for whatever reason.

To make things worse, I’ve now tried disconnecting the jacks entirely and am seeing the exact same behavior in the main unit. Is this just what the Audio IO 1u does when nothing is connected to the jacks pins? Does it indicate that my jacks module is defective in some way? I’ve had it for months but never used it because my Audio I/O has always lived in my 7u until now.

Ok so although I did read through a number of discussions about this module in search of answers before posting my own issue, it naturally wasn’t until shortly AFTER posting this that I finally found an existing thread about this very issue.

Turns out that the problem was not with the Audio I/O 1u after all, but likely some other module being connected improperly in my 4u case. I disconnected all modules but the Audio I/O and sure enough, the LEDs were behaving normally with nothing else on the rails. So I then reconnected all of the other modules, powering on the case after adding 2 or 3 more modules each time to verify that everything was good. And sure enough, I’m now back to all modules connected and powered on, but this time no misbehavors.

I’m guessing that, due to the unshrouded headers on the old TPS30 and a healthy dose of my own carelessness, I must have plugged in one of the modules misaligned, such that a couple of the pins were not connected to anything and the rest of the pins were connected to the wrong lines.

Either way - if anyone runs into the issue of all LEDs on the Audio IO 1u being lit up despite nothing being plugged in, there ya go. The slow but steady way of resolving it.


Glad you were able to sort it out!