I am trying to understand how to improve grounding on the Polysix and hence decrease the output noise floor.
Thankfully, the cool Kiwisix peeps provide some recommendations in their manual, which I am supposing (correct me if I'm wrong) can also be applied if we do not have the Kiwisix upgrade, be it the KLM-367 replacement or the PSU upgrade.
The first modification is to link the Output jack GND to the VCF FM CV In GND. This is Link #1.
Most of the rest is linking the various analogue boards to the PSU's largest Capacitor -ve leg.And then finally, connecting Link #1 above to that Cap -ve leg (which looks to me like it's acting like a star-ground for analogue here after all those mods).
Now, by default, without any of the mods above, when I check with my DMM on continuity mode, the two points in Link #1 are already connected.
Furthermore, by default (without the mods above), the Output jack GND also already has continuity going to the largest PSU Cap -ve leg.
Now, if I understand correctly how things should be done ideally, the Digital circuits should have their own return, the analogue ones have their own returns separately, and the Digital and Analogue should come together at a GND point but at a single place on the board.
It seems to me that adding Link #1 and the final mod of Output jack GND to the PSU Largest Cap -ve leg is in fact adding two more avenues for interference between the Digital side and the analogue side.
Doesn't these two new links enable more avenues for ground loops?
If there should be a mod for proper grounding and separation of digital from analogue, shouldn't some existing links be removed if necessary, in favour of a new, single-point where they join?
I want to mention that this isn't any criticism against the recommendations of Murray and Kiwisix, I just want to understand the system better and to confirm (or deny) my understanding and potentially find a better way if there's one.
Yash