I've uploaded a youtube video of me trying a few different situations demonstrating the noise the Owl pedal produces. I'm using firmware v14. Hopefully this will help users and provide assistance fixing bugs.
It shows me using a Polytune2 with no input into a Scarlett 6i6 with the preamp cranked to show the noise floor. The highest it reaches is -66 db (RMS). This noise level is the same as many of my other pedals when bypassed. They all show -66 db on their own and when chained together using a Strymon Zuma isolated power supply, the highest they reach is -65 db.
The Owl pedal, when powered using USB brings the noise floor up to -40 db, even when bypassed and input/output gain as low as they can go, for a total of 26 db of added noise.
When powered using an isolated power supply (same one used for the Polytune2) and input/output gain bottomed out, the noise floor lowers to -48 db, for a total of 18 db of added noise.
Throughout this, I turn the remote control on and off, saving it to the Owl with no change to the noise floor, ruling out the knobs' ADC as the culprit. The block size also does not seem to have an effect on the noise floor either.
Changing the sensitivity to High, raises the noise floor to -45 db, bringing the total noise added to 21 db.
I then changed patches to another default patch, and then a user patch. The noise varied around 1 db with these changes.
This determines that the lowest amount of noise in an ideal setting is +21 db, which unfortunately makes it hard to recommend for any practical use outside of experimentation. +21 db imho makes it about 18 db too noisy for recording or practical live use. However, I'm not sure if this is a firmware issue or a hardware one. It's a shame, because I'd kill to be able to use some of these effects on my pedal board.
I've also tried firmware v12 with similar results.