I’ve had my OP-1 for a few weeks now, and I absolutely love it. I wanted to expand my synth capabilities, so I bought the Moog Model 15 app for my iPhone 7. The app works great as a line-in to the OP-1 through the mic input, but one issue I’m still having is some high frequency noise only present when plugged into the iPhone. My current setup is pretty simple: iPhone 7 --> lightning to headphone jack adapter --> 1:8" cable --> mic input. I’ve tried to use Nitro as a LPF, but it muddies the whole mix and I’d prefer to keep a crisp sound. Any ideas?
If any of the devices is connected to a charger try disconnecting them. Also make sure you rather up the volume on the iPhone than the gain on the OP-1. Ideally you’d want the gain to be 0 or less.
To check if the issue is OP-1 related or not you might also want to try and record your iPhone to a different device (e.g. Laptop/Desktop Computer).