I’m sorry to hear about your Quaverato trouble. Thank you for sharing that video, it is very helpful to hear what you are describing. That is a very annoying issue. It does sound very much like a ring modulator.
I have never experienced this particular issue, so we’ll have to try to troubleshoot it together.
First, please try to use a different power supply. A battery would be best to test the pedal out…if you have a 9v battery snap to barrel jack adapter:
…or something like it that would allow you to hook up a 9v battery to the pedal. I’m wondering if the pedal is getting clean enough power, that is isolated enough. This test will see if it is an issue related to the type of power supply that you are using.
Another test you could try is to use “calibration mode” to test each side (high and low) separately of the signal path to see if the issue is caused by the combination of the 2 sides (like a typical ring modulator circuit). I’m interested to see if the weird sound is still occurring when only one side (high or low) is heard.
Try these tests and let me know what you find.
Good luck.
-Brach