The difference between Ball, Loop ends & Other Knots
When strings were made with Gut they all had a knot tied with a loop at the bottom. This was used to loop the string through at the tailpiece or secured in the ‘key hole’ in the tailpiece.
With the addition of fine tuners and different designs of tailpieces with fine tuners, and of course the strings themselves, it became necessary to create different tie options. This means that you can choose between a ball end that holds the string in place (in the tailpiece or fine tuner fork) or a loop that is held by a fine tuner hook or looped through itself.
With Gut strings they are mostly tied off with a knot. Some knots are in loop form and some are simply a granny knot, as in the image below.
For versatility some string makers make strings that have a ball on the E string which can be removed if your string requires a loop to hook onto the fine tuner. Of course this is only possible to do with a steel string.
Natural gut and other synthetic strings are not possible to do this with because of the material nature which determines how it is attached to the ball on the end.
The difference between Ball end and Loop end.Note. Mainly professional musicians with a preference for a loop end E string will use this. In most cases you will be looking for a ball end set of strings – especially for anyone with fine tuners and or a regular tailpiece.