Electronics question

[Joe Nation]

I've got a single Fishman Fluence pickup to go in my 5-string project build. It comes with a push-pull volume pot, stacked treble/bass pot and a 3-way DPDT toggle switch to select the voice of the pickup. I'd like to fit a rotary switch in place of the toggle, so I can have three matching knobs. Would this 3-way rotary Schaller Megaswitch work?

 

My wiring skills are non-existent, so I'm all in a muddle about how these things work. The standard toggle has six tabs but the megaswitch has 12, I assume it's just a matter of establishing which tabs to solder and in what configuration, to get the right functionality. There are loads of schematics on Schaller's website are for wiring up conventional pickups in conventional configurations, but nothing shows the basic workings of the switch.

 

Edit: I just found this MEC switch, which looks similar but has 8 tabs. No schematics at all on MEC's website.

Edited April 8, 2022 by Joe Nation

[neepheid]

Wiring up rotary switches can be a mind-f. 

 

You sound like you're looking at 2P3T rotary switches.  That gives you 8 connections total (2 for the poles and 2x3 for the positions).  The 3 position Schaller switch probably only has 8 connections also, they were just too lazy to change the picture of the 2P5T (12 connections - 2+2x5)

 

I prefer to label the poles with letters and the connections with numbers.  In the case of the 2P3T, you'll have A and B, then 1-6.

 

In general, it'll work as follows:

 

Position 1: Pole A is connected to position 1, Pole B is connected to 4

Position 2: Pole A is connected to position 2, Pole B is connected to 5

Position 3: Pole A is connected to position 3, Pole B is connected to 6

 

In reality, you need to know how the switch you have works.  Hopefully there's documentation, otherwise there's a multimeter and a bunch of head scratching.

 

Now you need to know what the original 3PDT on-on-on switch is doing.  All it appears to be doing is selectively connecting some of the pins to ground.  This is borne out in the instructions.  Should be a pretty simple wiring, coupled with the fact that you're only using one pickup.

 

There are 2 connections on the pickup for voice selection, they are labelled Voice 2 (pin 1) and V2 MC Off (pin 3).  Coil tap is a separate concern - use the push/pull provided to do that as per the instructions.

 

For voice 1, neither of these connections should be connected to ground (ie. left open/high)

For voice 2 (mid cut), ONLY pin 3 should be connected to ground

For voice 3 (mid flat), at least pin 1 should be connected to ground.  In the standard wiring, it connects both to ground and pin 1 trumps pin 3 which is handled by the pickup.  I don't know if this is necessary, if I'm reading the wording of the instructions correctly.

 

I'd connect both poles of the rotary to ground.  Then I'd take pin 1 and connect that to output 2.  I'd take pin 3 and connect it to output 6.  To mimic them both being connected to ground in position 3 (if that's necessary), I'd make a link between output 2 and output 3.

 

 

So in position 1 (red), neither of the pins are connected to anything (voice 1) (because the rotary is connecting A -> 1 and B -> 4)

In position 2 (green), pin 1 is connected to ground,  pin 3 is connected to nothing (because the rotary is connecting A -> 2 and B -> 5)

In position 3 (blue), pin 3 is connected to ground (because the rotary is connecting A -> 3 and B -> 6).  If you use the link from 2 -> 3 then pin 1 is also connected to ground in this position, mimicking what the DPDT on-on-on is doing.

 

I hope that helped, and please someone tell me if I've got this horribly wrong.  I've only done this once before, albeit a more complicated 4 way scenario with 2 pickups.

 

[Joe Nation]

You're a legend, thanks @neepheid. I think you're right about pic of the Schaller, it's an M model which is 5-way. I've done some other research and although I couldn't find exactly what I needed, I think I've got it figured out - unless anyone else cares to weigh in?

[Joe Nation]

https://www.fishman.com/wp-content/uploads/2020/06/Fluence-SB1-Single-Bass-Pickup-w-Dual-Concentric-2-Band-EQ-1x9V.pdf

This is Fishman's wiring diagram for a single Fluence pickup, the 3-way switch is bottom-right. Looks like the black wire is the ground, the orange wire is pin 1 and yellow is pin 3, as per your diagram. I think you're right about the (off/off)(on/off)(on/on) switching of those two wires.

 

I thought about trying to do something really cool with the coil tapping, like humbucker/inside coils/outside coils on another rotary, or even a 9 way switch with a single position for each possible combination. But that seems like a bit too much faff for my taste. I'll stick with the push-pull volume knob for now.

[neepheid]

19 minutes ago, Joe Nation said:

https://www.fishman.com/wp-content/uploads/2020/06/Fluence-SB1-Single-Bass-Pickup-w-Dual-Concentric-2-Band-EQ-1x9V.pdf

This is Fishman's wiring diagram for a single Fluence pickup, the 3-way switch is bottom-right. Looks like the black wire is the ground, the orange wire is pin 1 and yellow is pin 3, as per your diagram. I think you're right about the (off/off)(on/off)(on/on) switching of those two wires.

 

I thought about trying to do something really cool with the coil tapping, like humbucker/inside coils/outside coils on another rotary, or even a 9 way switch with a single position for each possible combination. But that seems like a bit too much faff for my taste. I'll stick with the push-pull volume knob for now.

 

In a single pickup situation, I doubt changing which coil is used in single coil mode would yield tonal differences worth the hassle.  Changing inner/outer coils makes more sense in a 2 pickup scenario where it can alter the effective physical distance between the two coils remaining in service when both pickups are used together.  Even then, it smacks of "because I can" rather than creating any earth shattering sonic revelations.

 

When I did a single coil mod on a G&L Tribute L-2000, I simply decided that I'd use inner coils - that way I had a very rough approximation of an L-1000 in parallel and I dislike Jazz basses so I didn't see the point in doing outers.  Turns out I don't even care about bridge pickups, but it took me a few years to figure that out

 

In a single pickup scenario, just decide if you want it slightly more bassy (use north coil) or slightly less bassy (use south coil).  I like my basses to sound bassy, so if it was me, I'd favour north in this scenario - but I doubt it makes much of a difference either way.

[Joe Nation]

That's a good point, glad I didn't waste my time figuring it out! The Fluence has a solder bridge on the PCB to select the default single-coil, but you can wire it to a switch. I doubt my useless ears could tell the difference either way.

 

I have also just come across - I think - a push-pull 3-way rotary, so I could have the coil split on the same knob as the voices. Not sure if it's worth the hassle frankly, but I think I'd prefer if that way.