[SOLVED] 24i random dropouts during recording

[fret]

I've been using a 24i for the last 6 months plugged into a 424pci card in a PC to record the house band each week in an auditorium. There are 3x8way looms running out of the (analog) Allen and Heath sound desk's direct outs and into the 24i. On the PC side I'm just using Reeper (spelling!? sic) to record to .wav and then I export the recordings to .flac and take them home to mix on Logic. This all worked great for the first few months. No issues.

Then I started getting sections of audio where the signal would go from normal to extremely quiet for about 30 seconds to a minute. And it's getting more and more frequent. To the point now that most of the recordings are useless because of all the missing audio. Sometimes I can rescue it somewhat by chopping up the audio and normalizing the different sections, but usually the signal is buried so far down in the noise floor that I give up.

Now at the same time the MOTU unit is effectively recording silence the desk is pumping out normal signal to the FOH speakers. No drop outs are heard from the desk side of things so it's not an input issue. I'm also not ruling out the sound desk's direct outs.

So far I've tried reseating all the cables without success. And next week I'll record 8 of the channels using a separate system (FA-101 -> macbook) to see if I can reproduce the issue using a different recording method. If I can that means the desk is at fault. If I can't, or only the MOTU recorded channels drop out then I can assume it's a 24i related problem.

Reeper is running only the default settings. I haven't changed anything much there. It's really just capturing the audio to disk at this point. I'll try upping the buffer size just in case next time I record.

Is this a known issue? Or something new?
Are there other things I can try to isolate the issue?

Thanks.

[fret]

I decided that I wasn't going to wait till next week to go back and run some tests.

First I isolated the Motu 24i and the PC, by running 8 tracks of audio from my macbook + FA-101 in and recording that. After 10 minutes or so no issues.

Secondly I isolated just the sound desk, by running the same 8 tracks into the line ins of 8 channels, then took the direct outs back into the inputs of the FA-101. And when I recorded that... several channels dropped out within the first 2 minutes. Bingo. It's the desk

So nothing to see here... move along everyone.