custom bass wiring - cap switch

[flateric]

Happy new year chaps! A quick question for your delictation.
Consider if you will a 2 pickup bass set up with a 3 way pickup selector switch and each pickup having its own independant volume and tone control. Now I want to add a 3-way on-on-on mini switch to switch in 2 different value capacitors (and have one position where it is bypassed) in order to access 3 different tone ranges. Think, if you like, the vintage treble switch they put on the Rickenbacker 4001. Now doesn't the cap have to be attached to the tone pot? In which case, would the switch only work via one of the tone post and therefore only one of the pickups - whereas I want this switch to act independant of whatever pickup combination is chosen.

[ChrisK]

I want to add a 3-way on-on-on mini switch to switch in 2 different value capacitors (and have one position where it is bypassed) in order to access 3 different tone ranges.

Simple is.

....doesn't the cap have to be attached to the tone pot?

Yeah, that's what makes it a tone circuit.

In which case, would the switch only work via one of the tone pots and therefore only one of the pickups - whereas I want this switch to act independent of whatever pickup combination is chosen.

Again, simple is. Leo solved this over 50 years ago to save cap coin in the first Strat. The cap is shared in the leg to signal ground from both pots. This is where you'd place the switch.


So, since we've been discussing exactly this concept most recently, I'm gonna say, "hey, pay attention."

This one gives three cap values from two caps.
Free "Woman Tone"

If you look in The Demented TeleBlender, S2 puts two caps in sequential value order to realize three values.

Now, if'n you take wolf's circuit posted by cyn1 and use a SP3T Center-OFF switch, you will have no cap in the middle position.

Wolf's site is a great resource for ideas and inspiration.
www.1728.com/guitar.htm

Don't be concerned that the pot is connected to signal ground and the switch is connected to the signal. (Your only clue is that series networks are not affected by the positional order of their linear components, and are also not affected by "gravity".)

Now, there will be some slight interaction between the pickups if both of their tone controls are turned down and only one is selected, since they will be sharing a common capacitor. If this is a problem (it might be a neat feature, what do I know), use a DPDT Center-OFF switch and two caps per section/pickup/tone pot.


This cap sharing can also be easily done with a DP3T Center-ON (ON-ON-ON) switch, but the same interaction issue will exist.

Since you prob'ly have the DP3T Center-ON (ON-ON-ON) switch, use this for reference.

Fun With Toggles & Push-Pull Switches

[flateric]

Chris - you're a star. Off to ponder now....