Thanks for the response Takumi. Unfortunately, that’s the issue though. In my guitar pedal, I do have the op amps before and after the seed rev7, and that noise becomes audible. Doing the experiment without the seed was to try to figure out if I could rule out the actual guitar pedals being the issue.
Here is an experiment for you all to try. Take 2 of the Daisy Petal hardware (my guitar pedal uses the exact same op amps and signal chain) and put Rev7 seeds in them. If you connect a guitar to 1 and then to an amp, you will hear no noise in the signal. However, if you take 2 Daisy Petals and daisy chain them. So the signal goes from Guitar → Petal 1 → Petal 2 → Amp, my bet is you will get the same noisy signal I’m seeing. If you were to put Rev5 seeds in both of those Petal’s you would not.
It’s also not a ground loop, as I’ve done this powering all devices from batteries and the issue remains.
My current theory (and I’m no EE) is that this new Audio codec in the Rev7 seed is expecting the outputs to be loaded, and when they are loaded even just a little bit, the noise is gone, but the op-amps at the output and then input of the next pedal are actually preventing the outputs of the first seed in Petal 1 from being loaded enough, and that same noise we saw on just the seed by itself persists but is now amplified.