Issue with ddj 1000 sound quality

Hi, I’ve had the ddj 1000 for a couple of months and had no issues with it but suddenly the sound quality has just gone. The tracks are really crackling and vocals keep breaking up. If I record anything it’s even worse. I don’t think it’s rekordbox as if I listen to tracks on rekordbox through my headphones plugged into the computer everything is great, any ideas?