Shifting Gears: The Series/Parallel module

[reTrEaD]

Whether we're talking about two coils of a HB pickup or two pickups, switching between series and parallel mode is a useful way to alter the tone. Series provides more output and increases the inductance (causing a darker tone). Parallel produces a brighter tone.

In following drawing we look at the connections necessary for Series or Parallel individually, then how to switch between the two. In this example we see two coils, as we would have in a HB pickup. Hence one coil always has it's (+) lead connected to hot, the other has its (-) lead always connected to ground. This is Local switching.





In Global (aka System) switching, we could have as many as all four connections routed to a pickup selector. But we'll cover that in another thread.

I've introduced some new labeling. It might be handy in future discussions. The labels are in two parts. The first refers to the function in the series mode. The second refers to the function in parallel mode.

The (+) of the Red coil is labeled as Hot/Hot.
The (-) of the Red coil is labeled as SL/Gnd.

The (+) of the Blue coil is labeled as SL/Hot.
The (-) of the Blue coil is labeled as Gnd/Gnd.

These designations might seem unnecessary now but when we look at using the S/P switch in a Global sense, embedded to a pickup selector, we won't always be pairing those connections the same way we are in the Local application.

Here are a few examples of additions.

[newey]

RT-

Great stuff! Now we can simply point folks in the direction of this thread for numerous series/parallel queries.

[blademaster2]

I used DiMarzio "Dual Sound" humbuckers for my first guitar I built, where they essentially included a DPDT switch in a Super Distortion pickup design with a coil tap.

I was expecting night and day difference: double the signal/inductance for series, half the signal/inductance with parallel. I know now why I was slightly disappointed (I was a teenager then and I wondered why they sounded so similar), the signal strength change is small on a db scale, and the inductance difference is audible but not profound especially for a tube amp input impedance and a good low-capacitance cable.

I do appreciate the difference now, but I have had much more variation in a more recent guitar where I selected single coil versus humbucker (on that axe I have a six-way rotary switch so I get series, parallel, out of phase, single1, single2, and single2 phase-inverted).

[Charlie Honkmeister]

Ummmm....   excuse me  reTrEaD ,  but wouldn't your  series/parallel switching diagrams  be incorrect for a humbucker,    since the coils are going to be in phase, and because they are in phase but working with different magnetic polarities,  will mostly cancel the string signal,  and not cancel the hum?  


Series link humbucker:    two winding starts together for series link,  or two winding ends together.   Electrically out of phase in series.  Magnetically in phase for string signal. 

Parallel link humbucker:   winding start of one coil to winding end of the other coil,  x2.   Electrically out of phase in parallel.  Magnetically in phase for string signal.  

Check the drawing below to see what's happening with the starts and ends of the coil windings.  

[reTrEaD]

starts and ends

The (+) and (-) on my drawing do not indicate starts and finishes. They indicate string-sensing phase. So they're 100% correct.

[Charlie Honkmeister]

OK,  thanks,  got it.   Since we are used to seeing pickup color codes ,  start/end wires,  etc.,  it was a bit confusing.

[Charlie Honkmeister]

Thanks very much for the diagrams!   Appreciate the clear drawings of some of the variations that are possible.

[reTrEaD]

Thanks for the compliment. Nothing groundbreaking here but I thought organizing it together in a visual form could be useful.