Noise output from VCV to 2600 via MOTU

Hey y’all.

So I picked up a MOTU 828mk3 so I could have DC coupled outputs from which to route CV from VCV Rack to some external synths, like the Behringer 2600 and a Pro 3. I have it routed like this:

VCV: LFO out to Audio module output (corresponding to the analog out on the MOTU)

Patch cable from MOTU analog out into 2600 FM on OSC

So, the LFO is modulating.

Now, I’m trying to run an audio signal out as well. So it’ll go from an OSC out to Audio module output to a 2600 audio input to the filter.

I noticed yesterday, when I ran the audio signal, there was a rhythmic clicking on top of the OSC out. And then to troubleshoot, I ran the LFO again to modulate the OSC on the 2600, and there was an intermittent flutter, almost like there was interference, that sometimes shows up and changes in frequency.

So I’m trying to narrow down where the problem is, and I’m thinking it is the MOTU at least.

  1. Scope in VCV rack doesn’t show any aberrations. Audio out directly to headphones does not have the same issues.

  2. Running CV pitch or modulation from a Keystep to the 2600 does not create the same issues.

Is the basic routing correct? Could it be a cabling issue (I’m using Hosa unbalanced 1/8th patch cables with a 1/4 to 1/8th adapter at the MOTU. Is it possibly a power issue at the MOTU? Or sampling rate? Possibly a software setting?

Any help would be appreciated, or tips on how to further troubleshoot.

Nevermind fixed it. There was some weird noise with the MOTU. Updated firmware on it and now working as expected.

Now… for some CV inputs.