Does anyone have first hand experience with installing one of these? It's really just a resistor & cap but where does it go? My setup is 2 humbucker 1 vol 1 tone.
I don't know about this one but others put the cap and resistor in parallel with each other and in series to the split coil, black and green neck and white and red bridge in the above diagram.
Before you do that, listen to some YouTube clips if partial coil splits with a capacitor. In my opinion they sound awful. Muddy as well as thin. Really unbalanced EQ. What I find works really well is grounding via a 4.7k resistor which is just enough to stop it sounding really thin and when split has a decent single coil tone.
Something I have done to one of my guitars is the above but instead of going to ground it goes to the middle lug of a pot set up like a volume pot to give variable coil split so I can fatten single coil tone or add sparkle to humbucker by controlling the amount of coil split
Here it is in a strat, 3 push pulls - one volume, one master tone one variable coil split plus neck and bridge on .
Only when split if you look at my diagram you can see R4.7k indicating where the resistor goes for variable coil split. Otherwise the bridging wires go to middle lug on one side of the push pull, and the resistor goes from the pull lug in the same side to ground.
I highly recommend you do it on both - otherwise you'd miss the magical combo of single tone bridge with humbucker neck.