Thanks for the replies, although it seems to be the answer to a slightly different question lol (unless you are actually answering someone else's question, in which case my apologies for the misunderstanding!).
I know I can use my favourite music to burn it in - and I will be; but my question specifically is regarding whether it's safe to use the iBasso burn-in cable (plus their 4.4mm adaptor) with the WM1Z plugged in and playing continuously 24-7 until the 200 hours is reached?
I'm often getting an hour or less of listening time per day recently, so rather than wait 200 days (!!) to be able to hear the modded WM1Z at its best, I'd prefer to just plug it in and leave it for 8 days or so and then incorporate it back into my daily routine, thus getting greater value for money in the process
But just need to check that's not going to do any harm to the unit/battery?