Help on custom bass wiring (3 x pickups)

Pickups, wiring schemes, switch techniques and onboard active electronics for guitars
Post Reply
Posts: 2
Joined: 06 Jan 2019, 21:45
Has thanked: 1 time

Post by MetaL »

Dear all, I'm designing a custom bass wiring and it would be great if you could give your feedback & comments. This was asked from a friend of mine who needs many tonal possibilities from his instrument, here are his requests:
  1. 3 x passive pickups: 1 x neck + 2 x bridge
  2. Possibility to combine the bridge pickups in series (with 1 x volume) or in parallel (with separate volumes for each pickup)
  3. Possibility to mix neck&bridge: neck only, bridge combination only (see item 2), neck + bridge combination
  4. Finally (phew...) master tone & master volume
I came up with a modified Jazz Bass wiring (please see the linked schematics & wiring diagram) that should handle all those requests.

My main doubts are:
  • When neck + bridge combination is selected (ON/ON/ON switch in the middle position, neck goes in parallel to the combined bridges. Each bridge PU goes through a 250k pot, while the neck PU signal goes "straight" with no additional load. Do you think that this could "kill" the bridge pickup signal (e.g. neck PU with much more volume than bridges)?
  • Before reaching the bass jack, signal is going through 4 x 250k pots. Is this OK in your opinion? Or maybe it is better to redesign the master tone & volume using different resistance values?
Of course any additional comment or fix is greatly appreciated ;-)
Thanks in advance!

User avatar
Resistor Ronker
Posts: 422
Joined: 29 Aug 2011, 07:14
Location: The Netherlands
Has thanked: 76 times
Been thanked: 81 times

Post by Cub »

Hello and welcome to the forum.

It's a bit late for my tired eyes, but I will say this. Please suggest your mate to use a blend pot with a center detente for the parallel bridge pickups setting. That would make thing dialling in the right mix of the two pickups a lot more intuitive. On top of that, it will save you some real estate on the pickguard or control plate.

It doesn't look that terrible to operate like that either. Pickup selector switch, master volume pot, master tone pot, bridge mix pot, bridge mode selector switch.

I wish I were a chestnut tree, nourished by the sun.
With twigs and leaves and branches and conkers by the ton.

Posts: 2
Joined: 06 Jan 2019, 21:45
Has thanked: 1 time

Post by MetaL »

Thanks for the suggestion Cub; I agree with you that the blend pot would be a simpler alternative (would also be my personal preferred choice!)
The dual-volume approach is actually a specific request from my friend that wants to explore something different from the classical blend approach.
Let's see if I can steer him in the blend direction ;-) Thanks again!

Breadboard Brother
Posts: 55
Joined: 31 May 2018, 18:26
Has thanked: 17 times
Been thanked: 13 times

Post by thetragichero »

master volume + either individual volumes or blend/pan pot + tone control(s) is a whole HECKIN lot of potentiometers loading down the pickups, meaning they'd need to be 500k-1M or you'd suffer quite a bit of treble loss. this is not even taking into account how user-unfriendly those controls would be (and possibly useless/not worthy of the real estate required/hassle/component cost)

so tell me a little more about the pickups. you mentioned 1x neck 2x bridge pickups, instead of neck/middle/bridge like a strat (which only have a selector switch, 1 volume, 2 tone, for what it's worth). am I tho believe that the two bridge pickups are physically close to each other? if that is the case, then much like a bridge humbucker in a guitar each coil of the pickup briskly sounds the same so either or as a single coil is a waste.

so now I will digress about my main bass....


same configuration as an older American deluxe pbass but the body was parted out from a blacktop pbass
anyway... this originally had master volume, master tone, 3-way selector switch like a Gibson, and coil split for the bridge
didn't like the coil cut (hum + sounding like the full humbucker but quieter = not happy chris) 3-way switch could switch between pickups quickly but not very useful
now it is master volume, pickup blend, master tone, series/parallel for the bridge
unlike a guitar, I find being able to blend between pickups extremely useful (my usual tone is just on the favoring pbass side of the center detente. just enough attack and high mids to fill out the low-mid growl), will favor the bridge side with bridge in parallel and tone turned down for more arpegiated things
all in all it is quite intuitive and simple
(of course I'm going to add another hole put in a preamp to give treble and bass knobs but I guess this is why I can't have nice things lol)

anyway, that was a lot of words. I hope this helps flesh out what should or shouldn't be on there based on my experience

Post Reply