Five-way rotary selector switch for two pickups

[Ricky Rioli]

Just wondering about the feasibility of this idea:

Two noiseless Jazz pickups

Five-way rotary selector switch:
1. Neck only
2. Both pickups, a trim pot cutting the Bridge
3. Both pickups on full
4. Both pickups, a 2nd trim pot cutting the Neck
5. Bridge only

 

[toughluck]

This means you need three holes, one for the switch, two for each pot, so it's not because you don't have room for a lot of components in there, correct?

What exactly are you trying to achieve? Two separate trim pots per pickup do the job without an extra switch, I guess you're interested in quickly switching between the settings without playing with blend?

It's feasible. You need a 2-pole (A-B), 5-position (1-5) switch.

Wiring:
- Neck pickup hot to A
- Bridge pickup hot to B
- A1 to A3
- A1+A3 bypass the trim pot (connect to output side of the neck trim pot)
- A2 to neck trim pot
- B5 to B3
- B5+B3 bypass the trim pot (connect to output side of the bridge trim pot)
- B4 to bridge trim pot

This wiring does what you're trying to achieve. You might be interested in a sixth position where both pickups go through their respective trim pots. If yes, then adding it as an extra position (position 6), you just need to go A6 to A2 and B6 to B4.
If you want it as an extra middle position:
1. Neck only
2. Both pickups, a trim pot cutting the Bridge
3. Both pickups on full
4. Both pickups to trim pots
5. Both pickups, a 2nd trim pot cutting the Neck
6. Bridge only

- Neck pickup hot to A
- Bridge pickup hot to B
- A1 to A3
- A1+A3 bypass the trim pot (connect to output side of the neck trim pot)
- A2 to A4
- A2 to neck trim pot
- B
- B6 to B3
- B6+B3 bypass the trim pot (connect to output side of the bridge trim pot)
- B5 to B4
- B4 to bridge trim pot

 

[WestyBassBob]

Seems unnecessary. Wouldn’t a simple VVT or T/Blend just be better?

 

[Jerry Catanescu]

Yes, it's possible and I've even done it once in the past. You need a double decker 5-position rotary switch (2P5T). The advantage versus VVT or a blend pot is recall-ability of one's favorite blended tones, that you can perfect with internal trim pots if you want.

 

[Ricky Rioli]

I've even done it once in the past

From the sounds of things, the only potential problem is lack of space in the cavity under a pg. Is the rotary switch much wider than a standard pot?

(example of a typical cavity pinched from a Google image search)

 

[Jerry Catanescu]

I don't really recall which switch I used, it was a long time ago, but it wasn't one of those huge clunky ones, if you know what I mean. Certainly not larger than a large pot. And very easy to turn, not much force needed. Probably a C&K, I'd think, based on my past habits...

 

[bench]

I zhink that's kind of what they fo on john myungs bongo....

 

[Ricky Rioli]

I zhink that's kind of what they fo on john myungs bongo....

THANK YOU!

I've had a vague memory of reading about a selector like this years ago, before I really understood how useful it would be, but couldn't for the life of me remember which bass it might have been

No, EB do not want to tell us how they do it:

 

[Jerry Catanescu]

I'd do something like this:

 

[fig]

I'd do something like this:

Quick question. Would the rotary switch be a 'make-before-break' or a 'break-before-make'?

I'm guessing 'make-before-break', but not sure.

I like the idea of having a few favorite preset mixes. Your circuit is going in my 'maybe someday I can use this' folder LOL.

Thanks.

 

[Jerry Catanescu]

Quick question. Would the rotary switch be a 'make-before-break' or a 'break-before-make'?

I haven't thought about that, TBH. I just used a switch I had on hand, which was very likely break before make (they're more common). It probably doesn't matter much unless you plan to switch settings in the middle of playing a note.

 

[micguy]

Break before make would be better in this application - that means that, for a very short time when switching, you'll have both contacts shorted together - with a passive bass, that's just fine. Break before make means that, for a short time, you'd have no signal (except maybe hum), which would be an issue if you switched while a note was going on.

If you use the "wrong" switch, you won't blow up anything.

 

[Jerry Catanescu]

My G&L bass has a factory 3-way mini toggle selector (ON-ON-ON). It's certainly break before make and it's never bothered me. I haven't heard other G&L players complain about that either.

 

[fig]

I haven't thought about that, TBH. I just used a switch I had on hand, which was very likely break before make (they're more common). It probably doesn't matter much unless you plan to switch settings in the middle of playing a note.

I never really thought about it either 'cause I rarely use rotary switches. Recently, though, I'd re-drawn a toggle actuated circuit to rotary actuated. Make-before-break was the better choice, so now it's on my mind LOL. As micguy just said, nothing would blow up. But there's always that tiny possibility of spontaneous inter-dimensional transference...

Break before make would be better in this application - that means that, for a very short time when switching, you'll have both contacts shorted together - with a passive bass, that's just fine. Break before make means that, for a short time, you'd have no signal (except maybe hum), which would be an issue if you switched while a note was going on.

Am I misunderstanding something?? That first sentence sounds like a description of make-before-break?

 

[Ricky Rioli]

I'd do something like this:

View attachment 7251283

What's the thinking behind the choice of 50k pots?

 

[Jerry Catanescu]

They don't have to be 50k but it seems like a sensible value to me. They're wired as variable resistors in series with the pickups to drop some voltage to taste in positions 2 and 4. They can go anywhere between zero and their max, so the max value doesn't matter that much if you never get to it. You can try 100k if you want. No harm done. I actually replaced them with fixed resistors once I found out which values I wanted for my particular bass and pickups.