| The problem with having three tone controls in a passive setup is that when the volumes are all the way up, the tone controls will act as masters. All three tones will have the same effect over the entire signal.
There are two ways around it, but both come with a compromise.
One way is to actively buffer the signal paths from each other, but this means you will need a battery, and of course, the pickups will not load against each other the same way they do in a passive setup.
The other way is to add resistors in series with the signal paths, to isolate the signal paths from each other. This means a drop in output and treble, however.
It would be a much better idea to simply have one tone control for all three pickups. | 
