Those 2 resistors at the bottom are forming Vref....V+ > R1 > R2 >GND and Vol 1 is connected at the junction...so Vref. I should have labelled my wee arrows sorry
. When doing this I always look for 2 resistors of the same value from v+ to GND first. Having no reference point like this makes tracing very difficult...loads of components seeming connecting all over the shop on a schematic
The cap on Tone 2 is definitely the Output cap (purple trace)
Tone 1 has a cap to Vol 1 (Vref) and a restore from the out of Vol 2
Tone 3 has a cap from Vol 2 output AND a resistor to Vol 1 (Vref again)
It's definitely BMP.
Vol 2 does go to one of the cap...and that goes to Tone 3 forming the High Pass side
Vol 3 isn't connected to any cap. Only the resistor coming off Pin 6 (as shown in your pics)
Your colour trace is spot on. I think the confusion was just with identifying Vref. It's the long yellow trace going from Vol 1, all the way round to Boost 1+2 and all the way to the top 2 resistors.
But hey....between us we just saved someone the cost of a weeks holiday in Magaluf