Annoying digital noise (sort of regular clipping)

hello,

I’m new to the forum and on my steep learning curve with Audacity.
I use a 2010 mac book pro with lion operating system.
I use a Roland Quad Capture audio device through USB 2.0.

No problems to record or mixing. but few seconds into the playback from audacity or exported files, a fast clicking (sounds quite digital) appears and ruins all the recording. seems to me that it kicks in when more than 2/3 tracks start to playback, including stereo and mono recorded ones.

I was wondering if that may come from buffering / jitter or any other set up?

i appreciate your help !! thanks a lot!!

Cristianna

https://forum.audacityteam.org/t/new-os-new-audacity-glitching-help/47975/6