On the output stage of a 001, 1 voice is ‘hard panned’ to the left and 1 voice to the right. This means that, if you are in Poly mode, you will hear 1 note on the left output followed by 1 note on the right output and so on.
This was a conscious design decision: each 001 voice is purely analogue from the oscillators onwards (no DSP, no DA conversion) and we are able to obtain excellent Signal to Noise Ratio (SNR) from the outputs.
Also, voices can be distorted (Drive) and stacked (Stack mode) - the sum of these is very hot and for this reason we send half the voices to output L and the other half to output R.
The solution to this on 001 is simple - if plugging one jack only to the right output, you will have both voices coming out of the same (R) output channel.