As Mastermold mentioned, 70's is not the highest point in Fender's production quality. But there are some nice basses from that era that lived up until now as well (I would love to see some statistics on how many of the Fenders lived up to now).
I would personally divide the 70's into two sub-periods. Up until 1974 when Fender started switching to the 3-bolt neck joint, it is more likely to find a decent bass in my opinion. However, as of 74-75, they started using the heaviest possible ash on earth and the neck joint was so poorly designed that the already bad neck joint construction became even more obvious (try to shake the bass downwards and see what the neck does on a 3-bolt joint). I find most of these basses with the heavy ash bass and treble heavy but lacking mids. So I would definitely stay away from these... Again, this is just personal preference. It might work for someone else.
In the meantime, I have a '73 bass which is quite fine (and people love it as well). I remember going to the Main Drag Music in Brooklyn, NY to look for a pedal, but when I tried the pedal with the JB, I fell in love with it and ended up buying it. I must admit, though, when I tried a brand new Jazz Bass a few years ago, I wanted to get rid of the '73 and get that one right there. But the whole "vintage" thing stopped me from doing that. Not that I even care, as I replaced the original pickups with some Fralins and changed the control panel with better caps and pots, so no more authenticity!
Anyway, if you do not have the budget for a Fender from first half of the 60's, and you like to have a "vintage" Fender, first few years of 70's might work, but you really have to spend some time to find a decent one. I find most basses from those days having neck/truss rod issues. So, rather than spending all the time and money, I would go brand new or a Custom Shop... IMO and IME...
I would personally divide the 70's into two sub-periods. Up until 1974 when Fender started switching to the 3-bolt neck joint, it is more likely to find a decent bass in my opinion. However, as of 74-75, they started using the heaviest possible ash on earth and the neck joint was so poorly designed that the already bad neck joint construction became even more obvious (try to shake the bass downwards and see what the neck does on a 3-bolt joint). I find most of these basses with the heavy ash bass and treble heavy but lacking mids. So I would definitely stay away from these... Again, this is just personal preference. It might work for someone else.
In the meantime, I have a '73 bass which is quite fine (and people love it as well). I remember going to the Main Drag Music in Brooklyn, NY to look for a pedal, but when I tried the pedal with the JB, I fell in love with it and ended up buying it. I must admit, though, when I tried a brand new Jazz Bass a few years ago, I wanted to get rid of the '73 and get that one right there. But the whole "vintage" thing stopped me from doing that. Not that I even care, as I replaced the original pickups with some Fralins and changed the control panel with better caps and pots, so no more authenticity!
Anyway, if you do not have the budget for a Fender from first half of the 60's, and you like to have a "vintage" Fender, first few years of 70's might work, but you really have to spend some time to find a decent one. I find most basses from those days having neck/truss rod issues. So, rather than spending all the time and money, I would go brand new or a Custom Shop... IMO and IME...