With the rotary pickup selector, I needed to check what the specification needed to be. At the least, the following settings were going to be needed:
Bridge only
Bridge + middle (maybe out of phase)
Bridge + neck
Neck + middle (maybe out of phase)
Neck only
Normally for a three pickup strat style layout, a 2 pole rotary switch is enough. The neck and bridge pickups can share a pole because they aren't in use at the same time. But in my set up above, I would need at least a 3 pole switch, one for each pickup because I was combining bridge and neck. However, when the low pass filters were taken into consideration, there was also the challenge of how to sum three pickups into two channel eq.
Luckily, a four pole rotary switch would probably work, if I summed the four poles into two sides. Each pair of poles into one of the two filters. But there was still the challenge of how to manage the middle pickup in the settings. Again that would be possible if I assigned two of the four poles to it and had the middle pickup switch from one channel to the other, depending on whether it was summed with the neck or bridge pickup.
This arrangement does have the disadvantage of upsetting the filter settings with a pickup shift from position 2 to 4 but that would only really be felt if I was playing it live and I have no plans to do that. This is a proof of concept, a prototype which I'll use almost exclusively at home and it's main trick is going to be position 3 anyway so I put together a circuit diagram (without phase switching for positions 2 and 4) as proof of concept where position 1 was now just the piezo and all the others were moved forward by one. Lustihand also advised that in their latest edition circuits, separate boost switches were no longer needed, the boost was activated by push pull pots so there was a welcome visual simplicity and logic to the layout despite despite it being pretty versatile.
But while I was browsing on the Stewmac website, I noted they offered 6 position rotary switches with four poles and I started to wonder whether that might be useful. Then I remembered I had a spare Graphtec acoustiphonic preamp left over from my Shuker Headless bass and a quick search of the Graphtec website revealed they offered piezo saddles for the Wilkinson VS100 series bridges.
That got me thinking about a clean piezo/acoustic type sound for one of the six positions so I threw it into the diagram and it seemed to work. It would sit with the overall mission of the guitar for cleans.
And I also had a spare hexaphonic PCB which opened up the possibilities of pitch-to-MIDI.
Hmmm.