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.