I set myself a little challenge with this one after reading Frederick Somerville's article on adding bass to the lower manual of his L-100....Frederick took a direct route by inserting an octavider pedal, giving him 16' tones available on the 8' drawbar.  I thought this was a very tidy modification but, as he points out, it is monophonic which means you can't accompany the bass with chords on the lower manual.

So figuring a way to play bass with the left hand and still have chords available left me two obvious choices, firstly to re-route pedal tones to the lower manual or alternatively divide the lowest 12 notes at the manual individually...I chose the latter and crikey...it took a fair bit of fiddling around before I got it working the way I wanted it!

The circuit took some time to come together, initially I got a single note divider working on a bread board using a signal generator to simulate the tonewheel source...easy peasy...then followed the fiddly stuff, adapting it to the actual organ!  Tonewheel coils are low-impedence...so the input had to be buffered to avoid losing signal on the 8' notes.  Tonewheel signals are a little 'hairy' and 'warbly' compared with pure sine waves...extra filtering needed!  Then getting the component count down while keeping the circuit behaving predictably was the next challenge...and so it went until I had weedled it down to 12 ICs to process the 12 individual notes...here's the result: