Don't know how high-end it is considered, but I just bought a new Audio-Technica AT33SA moving coil cartridge last week. I am at the 20 hour mark of the recommended 30 hour burn-in. When I first got it set up and started listening to albums, it sounded a bit thin. As the hours of listening increased the cartridge really started warming up nicely. Right now I am happy as it is sounding really nice. If it sounds better after 30 hours, then that is just a bonus!
