Passive tone into a Thumb system

[bajerovaquero]

Hello
I´m installing a used Warwick Thumb pickups and preamp in another instrument.
It has 4 holes so I was wondering about adding a passive tone to fill the 4th hole. Makes a lot of sense because you cant shape the tone in passive mode anyway...

Is this a straight operation I mean hot to 250k pot with capacitor and ground?
Let me know if it would work or the extra resistor will interact with the active system.

Thanks

 

[line6man]

Some Warwicks have active pickups. If that's the case, you will want a lower value pot.

 

[RobbieK]

^ true dat.

also, some people like to run a passive tone pot from the bypass switch so it only kicks in when the bass is switched to passive mode.

 

[bajerovaquero]

Thanks for your responses! I appreciate

Here is the wiring diagram:

There are pots of 500 100 and 25k ....
I¨m going to wire first a 500k pot between hot and jack and listen what happens if not work then a 50K

Also I got some 250k dpdt pot so could you provide some schematic RobbieK?


Thanks

 

[line6man]

Thanks for your responses! I appreciate

Here is the wiring diagram:

There are pots of 500 100 and 25k ....
I¨m going to wire first a 500k pot between hot and jack and listen what happens if not work then a 50K

Also I got some 250k dpdt pot so could you provide some schematic RobbieK?


Thanks

The pickups are clearly stated to be active. This means you should use a 25k tone pot. (Or 50k, to taste.) Additionally, you may want to try higher capacitances than would typically be used for passive pickups, because the frequency cutoff point of a tone control is partly dependent on signal impedance. 0.1uF is a good place to start.

Note that tone controls behave a bit differently with buffered signals than when they are allowed to interact with the impedance of a coil.

For a tone control that is only in the circuit in passive mode, use this diagram:

 

[JP Morin]

the thumb pre already have a preamp bypass build-in. a "passive tone knob" would be useful but I'd use the fourth hole for something else... or plug it with a non used dummy knob or switch... May be a EMG afterburner in it, or a drive circuit ??