January 17th, 2012
JBE on Series and Parallel Pickup Wiring
Series and parallel pickup wiring is sometimes a bit confusing. This is because we often use the terms “series and parallel” to refer to how pickups are wired together, as well as an optional wiring scheme for an individual pickup. However, the technical concepts of series and parallel wiring are the consistent across applications. This blog will describe what series/parallel wiring is and how we can use it when wiring pickups in our guitars and basses, or when seeking other tones from our pickups.
Parallel wiring is the usual way of connecting pickups in a guitar or bass. It applies to both single coil as well as dual-coil pickups. (Although the term humbucker is often used, the term is perhaps more aptly used to refer to a PAF-sized pickups, like our HB and HB Two/Tone ™ and Gibson’s and others, full-sized pickups. ‘Hum-canceling’ will be used to refer to other noiseless pickups such as our single-coil-sounding Gatton T-Style, S-Deluxes, J-Style Bass, and Soapbar (P-90) pickups for example).
With parallel wiring, each pickup’s signal goes to output independently from one another. Even when all pickups are ‘on’ they are essentially independent of the other pickups in the guitar or bass. Therefore, parallel wiring is conceptually:
Pickup #1 –> Output
Pickup #2 –> Output
In this example, 1+1 =2 (pickups) and each pickup can be turned on/off independently or combined by the switch. How is this logically wired?
Using the JBE color-coding, the black hot wire (+) of each pickup is wired to the pickup selector switch and the green cold wires (-) are wired to a good ground. (Please note that wire color–coding my differ among manufacturers, so you need to know each wire’s job.)
In contrast, Series wiring means that each pickup’s signal is first combined before it goes to output.
Pickup #1 –> Pickup#2 –> Output
To extend the bad math example, 1+1=1 (pickup), What!!!! The process of tying the pickups together logically combines them into one ‘larger’ pickup that has a darker tone and is somewhat louder. How is this physically wired?
A switch really does the work here. Electrically, the cold wire (-) of one pickup is connected to the hot wire (+) of the next pickup in a daisy chain fashion. Telecaster players may recognize that this as a Tele with a 4-way pickup selector switch or a Fender S1 switch in the volume pot. (P.S. For you Strat players, the Fender wiring and the application of the S1 switch is completely different from how it is used in a Tele).
It is also possible to apply the series/parallel concept not to a set of pickups but to an individual pickup – notably, a dual-coil (hum-canceling or humbucking) pickup. The two coils of a hum-canceling pickup are like two single coil pickups side by side, and wired so that there is a link or bridge between the coils where the (-) of one coil connects to the + of the second coil.
Here again, as in the generalized series example above, 1+1 (coils) = 1 Pickup. (Please note that since a single coil pickup has only one coil, there is no way to wire it in series to itself, but it can be wired in series to an adjacent pickup).
How can we use Series/Parallel Wiring?
All this series/parallel stuff got some folks to thinking about how to take advantage of it to create new tones. They argued that if they broke the series connection between a humbucker’s coils, they would be left with two independent pickups (coils), each with a set of + and – leads. By simply ignoring one coil you are theoretically left with a single coil (albeit noisy) pickup. Connect the coils back together and you return your pickup back to a noise-canceling humbucker pickup.
This is not new. Many of you will immediately recognize this as coil splitting, a common application which turns a humbucker into a single coil pickup. When connected to a switch, the switch makes and breaks the series and parallel connections. In this way we can achieve both a darker full-bodied as well as single coil tone from a humbucker pickup.
The trouble with coil splitting is that a humbucker coil on its own was not designed to produce a good single coil tone. The pickup was designed to have a fat sound and no noise. So, turning one coil off is not really a good idea. You get a faux single coil tone plus your humbucker is now noisy as a single coil pickup. JBE addresses this application in a better way with our HB Two/Tone ™. The Two/Toneemploys coil tapping vs. coil splitting to get true single coil tone with no noise. Moreover, you have the ability to switch noiselessly on-the-fly back to a full-bodied humbucker tone. See our website for a more detailed explanation. It’s really cool.
The main point relative to our discussion is that a dual coil pickup, by design, is a series connection between the two coils, and can be implemented in several ways:
1 Internal jumpers within the pickup itself,
2 Via a 4 wire cable that extends the internal jumper outside the pickup using separate wires so the musician can break and make a connection via a switch (series/parallel switching arrangement) to switch between humbucker and coil split tones
The majority of JBE pickups use a 4 wire cabling arrangement. Other manufacturers make the series connection internal to the pickup, making it impossible to split the coil as discussed above.
An alternative approach to coil splitting is to wire the dual coil pickup in a parallel fashion. Both coils remain operational and you can still wire the pickups to a switch to allow you to switch between the resultant tones. The parallel connection will be relatively noiseless and provide a more useful single-coil approximation than is achieved with coil splitting. But again, the best alternative is an HB Two/Tone™ pickup.
OK, great! Here is where it gets even more interesting. All JBE pickups are dual-coil hum-canceling designs. With a JBE pickup you can wire the coils in parallel to derive an open and somewhat stringy sound aside from the already great single coil tones these pickups produce.
A good application of this is with an S-Deluxe Neck/Middle pickup in a Strat (or Nashville Tele). By running the pickup’s coils in parallel and using a switch or push/pull pot to switch from its native series to parallel mode, you can get even more authentic in-between tones in the 2nd or 4th switch position of a 5 way switch. I tend to like this for quaky rhythms and to slightly thin the tone or get a more open/stringy sounds. Plus if you use a push/pull pot in place of an existing volume or tone control, you do not alter the guitar or bass to add a switch.
Series/Parallel wiring as it relates to guitar and bass pickups, refers to
1 How two (or more) pickups are wired to produce a thicker and darker tone by acting as one big pickup,
2 How one dual coil pickup can be wired to produce a more stringy, open tone, and improve the in-between sounds (aka out of phase) tones of your Stratocaster or Nashville Tele.
We discussed how breaking the series connection in a humbucker pickup allows you to coil-split the pickup.
Please note that JBE does not recommend splitting the coils (i.e. turning off one coil) of a T-Style, S-Deluxe, J-Bass or other JBE single coil sounding pickup model). These pickup models were designed specifically to deliver authentic single coil tone without noise. While it is certainly technically feasible split them using the 4 wire cable used for the pickups, the result is a low-fidelity sound that has minimum utility, other than as an effect, but which a player may find useful from time to time. Consider parallel wiring first.
We also discussed an application of parallel wiring for the middle position of your Strat or Nashville Tele that will enhance the in-between sounds of a three-pickup set.
Now, armed with this info, it is up to you to figure out how all the possible ways you can use these wirings to suit your playing and tonal tastes. If you’d like to share your custom wiring diagrams with us, please send a schematic.
Series/Parallel using a Push/Pull pot, 4-Way switch and Fender S1 wiring diagrams are available on the JBE website for your reference.