Fender Goes Fretless
Sometime in 1970 Fender introduced a fretless version of their iconic Precision Bass model.
By all accounts this bass was identical to any standard Precision bass, except all the frets and fret lines were removed.
However, being a fretless bass the neck was designedand constructed a little differently than a stock fretted P-Bass.
A normal fretted neck will have some relief (neck bow) to allow the strings to ring without rattling against the metal frets.
Ideally a fretless neck will be almost perfectly straight with virtually no relief, as there are no metal frets to rattle and buzz against. This allows the strings to be as close to the fingerboard as possible which enhances the overall fretless sound and allows easier playability.
The fretless sound is a more mellow, jazz like "mwah" tone that was made very popular by bass legend Jaco Pastorius. Jaco actually converted a Fender Jazz Bass by pulling out all the frets, filling them with putty and coating the fingerboard with marine epoxy in the late 1960's. Strangely, Fender did not capitalize on Jaco's popularity and offer a Fretless Jazz Bass version until the 1990's.
Who Used Them
I've personally played several fretless Fenders but have never owned one. I've always been fascinated by the fretless Precision bass and have even thought about building my own from parts. By most accounts the Fretless Precision Bass was not a big seller during it's production run. It seems it was viewed as more of an oddity or speciality bass rather than a genuine everyday axe by most musicians.
There were however several well known bassists that used this interesting Fender. John Paul Jones of Led Zeppelin played one on several tracks in the early 70's.
David J. used one almost exclusively with Bauhaus and Tony Franklin used a modified fretless P-bass to back several artists.
The original 70's fretless Fender Precison bass has now become quite collectable as they are fairly rare. It's not uncommon to see them go for well over $2000. Personally I think I'll just put together one of my own...one day.