Jack not playing well with Griffin iMic

I’m having trouble with using my iMic usb interface when using Jack audio in PD. Instead of a pure sine wave with the test patch I get a buzz. The problem is intermittent, sometimes it’s ok, but usually not. In the end I thought to disable jack in systemd to stop it loading at boot since the sound works well just with the alsa driver. However whenever I reboot patchbox seems to override the disabled setting in systemd and jack takes over the sound interface again, making it unavailable to alsa in PD. How would I go about disabling Jack in a more elegant way without causing problems for other patchbox modules?

What Jack settings are you using? USB devices usually need higher buffer sizes to work ok.

As for disabling Jack - Patchbox modules are depending on Jack to be running, otherwise their audio configuration won’t work.

You could try masking the Jack service and tinker around with launch scripts in /usr/local/patchbox-modules, but can’t say whether it’d work at all. If it doesn’t, you could come up with equivalent scripts for your needs based on the PB module scripts.

sudo systemctl stop jack
sudo systemctl disable jack
sudo systemctl mask jack

Thanks for your reply. Changing Jack’s settings makes no difference and under Alsa the iMic device works perfectly with a buffer of 64. I’ll investigate further and try the masking to see if it works. Ideally I’d like to have things working from boot without having to go disabling and enabling things.