I'm wondering. The Pi zero and Pi 1 have a processor with only one core. This core has only one thread (linux command: lscpu). During music streaming multiple processes are running. The CPU can handle only one process at a time. This means that the processor will interrupt the audio streaming sometimes. How is it possible that this isn't audible? Maybe perhaps the DAC chip has a buffer or that the interruptions are so short that the interruptions in the audio isn't noticeable?
Does a DAC chip have a buffer?