Background pulse noise


With the gain raised on the Mod Duo X inputs, there is an audible pulse noise. Deleting plug-ins from the web-gui will trigger this noise, as will scrolling past the Tuner menu item in the settings page. But even without these things causing it, the pulse will repeat on it’s own with some regularity.

How to reproduce

  1. Don’t plug anything into the Mod Duo X. Just have a pedalboard with a volume control and signal passing through the unit. So no real plug-ins being used. I used a level meter to monitor the signal.
  2. In the hardware settings, set the inputs to +12db.
  3. Turn off the hardware noise gate and compressor.
  4. You will hear background noise which sounds like USB traffic. Touching the USB cable input or power input can generate clicks.
  5. If you turn on the hardware noise gate, the issue becomes way more pronounced with clear pops each time the gate opens or closes - even though there is no signal going into the unit, the background noise will trigger the noise gate on and off and you will see the output green lights light up showing that there is some noise.
  6. You can remove the USB cable and still hear the regular noise.

Expected/suggested solution

At high gain, there shouldn’t be so much noise, particularly with no signal going into the unit.

Additional information

With the noise gate on at -60 db, you can hear clicks each time you delete a plug-in from the web gui. Also scrolling past the menu item “tuner” in the settings will always cause a click, if you are scrolling onto, or off of that item. This seems like internal processing noise.

More information is in this thread;

1 Like

Hi !

Sounds like the problem I reported some time ago. Background pulse, and weird low grinding sounds when turning the encoders or poking the unit nearby the PSU slot?
Support ended up offering a replacement with a test unit they still had, which i refused at that time.

The pulse is not present when you use the phones output is it? Only with the two TRS outpouts?