Well I managed to dig out another USB cable, still crackles! I turned Latency to 2 rather than 1 and the crackles stopped as soon as I hit ‘apply’. So it looks like it’s a latency issue, not good for somebody who likes to scratch 🙁
Can I do anything else here, seperate power supply or more ram?
Not happy as my old MacBook handled the latency better than this new one!