The oval pickups indicate it was either a copy of a Les Paul bass ('69-'71) and often called a 'Professional' because of its similarity to the Les Paul Professional guitar:
Or the '71-'82 Les Paul Triumph bass:
Both came with low-impedance humbucking pickups. The LP bass had a low impedance output only, so had to be used with either Gibson's dedicated low impedance bass amp, or an in-line matching transformer located at the input to a normal bass amp (you can get similar low/high transformers for mics). The Triumph came with an inbuilt matching transformer and a high/low impedance output switch.
The LP bass was very heavy as it was primarily driven by recording considerations (it was presumed it would be played sitting down). The Triumph was a lot lighter. Both had a 30.5" scale. The low-impedance design was pushed by Les Paul himself (like all the low-impedance guitars Gibson made). Les was a big fan of clean guitar sounds and rather forced Gibson to make the low impedance guitars and basses in order so that Gibson could still use his name on the new LP line ('68 onwards), even though a clean sounding Les Paul was not what most people wanted and they never sold that many.
They had a three position "tone selector" switch, three position pickup selector switch a phase switch (when both pickups on) plus passive treble and bass controls. Here, Gibson were showing off their know-how with passive inductor, capacitor and resistor tone-shaping circuits, similar to those used on the ES-345 and ES-355 guitars. They were reportedly very good basses with a very wide range of sounds.
Ibanez first made a Les Paul style bass, but with standard pickups and a LP guitar style 2 x Volume, 2 x Tone controls.
http://s93105080.onlinehome.us/Ibane...og/1971/17.jpg
But then from around '71 they also made copies of the two low impedance models.
http://s93105080.onlinehome.us/Ibane...og/1971/15.jpg. All the Ibanez bases had bolt-on necks.
Which version was yours, Smeggles?