Or even better get a vintage Moog Rogue - usually cost around 350 - 420 dependent on condition. Totally analog, not too big but have a decent keyboard and range and will hold their value. Many swear by them for sub bass, infact the Rogue was the synth engine of the Moog Taurus 2 bass pedals (the Moog on a stick as it was nicknamed ) I also have a Micromoog - rarer but equally useful for bass or lead sounds.