I have been thinking about your proposed sound and thought I'd give it a little go today. I made the patch: http://mbpatches.com/micro/?id=3825
(I found that sustain at 50% also produced good results)
and recorded it from the microbrute into a xenyx 1202 mixer (straight, no EQ or effects) into a Komplete Audio 6 into Ableton. In Ableton I put an auto-pan effect (not a preset, I just set Amt to 78.6%, Rate to .65hz, Phase to 240 degrees and Shape to 33.3%, which makes into a soft square wave, panning gently, but not overly predictably, left to right). That track was 100% sent to both the master and return A. On return A, I put the reverb preset 'large factory' and return A was itself sent about 75% to the simple delay preset 'dotted quarter note' on return B. I used these presets because I like them and if you have as low as the standard version of Ableton, you have them, I did not alter them. Finally, on the brute itself, I used some sequence I made a while back and tapped the tempo until it felt slow. While the sequence ran, I manually changed the release time on the envelope and the rate of the sequence to inject a little randomness, similar to the randomness with which ran falls.
This is the result:https://soundcloud.com/instantiate/rain1
The above is enough detail so that you could replicate the patch almost completely, assuming you have the same or similar gear. The simple version of the signal chain is this: micro to auto pan to reverb with a little delay. Even if this is very far from what you had in mind in your first description I hope you find it interesting or inspiring.