If you're hearing distortion from stylus wear it's likely to be much more apparent on the inner grooves. That was very apparent when I had an old, worn Koetsu. Try to determine if there's a correlation between the distortion and inner grooves.
700 hours should be perfectly fine in *optimal* playing conditions, but there's no telling how many actual hours it had before you, or how exactly it was treated / cleaned.
700 hours should be perfectly fine in *optimal* playing conditions, but there's no telling how many actual hours it had before you, or how exactly it was treated / cleaned.