The New Z-Series™ Pickups from Zexcoil®

You may have heard some rumblings about our new Z-Series™ pickups.

Well, the rumblings are true, we have been developing a new Zexcoil® platform for the past year or so. As you can imagine, producing a six coil, hum canceling pickup is expensive. Every part in a Zexcoil pickup is custom made to our specs, and we don’t share any common parts with any other pickup. You can’t go to a guitar parts supply house and set yourself up to make Zexcoils, like most conventional pickup winders can. We came to the realization that, in order to remain viable, we needed to come up with an improved version of our unique design that would retain all the good parts of our current line while being less expensive to produce. We did that, and more.

The new Z-Series pickups share much with our Legacy Series™ (the new name for the original line). Both incorporate our patented, hum canceling Zexcoil one-coil-per-string platform and both use our patented T3 Tone Tuning Technology™, our catchy name for the underlying materials engineering that shapes the tone of our pickups. The Z-Series is basically just a re-engineered version of the original Zexcoil, where we’ve communalized parts, eliminated unnecessary parts and removed multiple laborious production steps. In effect it’s a refined, improved and more efficient imagining of a Zexcoil in many respects.

Figures 1 and 2 illustrate exploded views of the Z- and Legacy Series pickups. These designs share the same bobbin and coil. Similar pole piece materials are used in both designs (with some differences that I will explain below). The Z-Series uses six magnets, a dedicated magnet for each bobbin/coil, while the Legacy Series uses only two, with each magnet serving a group of 3 coils. The Z-Series does not utilize the pole piece caps that most Legacy Series models do. Many of our models incorporate a laminated pole piece, and the pole piece caps on these models serve to provide a nice finished look, while also adding a significant mass of magnetically permeable metal in the flux path, close to the string. Since Z-Series models are potted in the covers, pole piece caps are not required. Potting in the cover also serves to eliminate a large part of the labor involved in producing a Zexcoil.

There are a few other things that make the Z-Series different, and in some sense “better” – at least more efficient from an electrical standpoint. One thing that isn’t obvious from Figures 1 & 2 is that we have rebalanced the coil and pole piece allocations in each slot. As a result, we get more of the output via pole piece mass (more magnetically permeable material in the core of the coil concentrates more of the magnetic flux in the core and results in higher output) so we can reduce the number of windings in the coils. Fewer windings yield lower resistance. So in tech speak, we get more Henries with fewer Ohms. We’ve also folded this improvement back into the Legacy line, because we can!

Elimination of the pole piece caps is effectively the elimination of an “eddy current speed bump” in the middle of the flux path. While the Legacy Series Zexcoils incorporate caps, these designs were also optimized around the caps being in place so they sound great the way they are. But the fact is, the caps aren’t required to generate a signal and when the caps are removed the pickup becomes more efficient. For instance, all other things being equal, a pickup without pole piece caps will generally have a higher Q value (see below) than a pickup with caps.

The incorporation of individual magnets for each coil also results in an efficiency gain. While we originally did it just to simplify the design (the Z-Series magnets are interchangeable in terms of North/South magnetic orientation – so only one part is required – while the Legacy Series magnets are “handed” – requiring two parts), what we didn’t appreciate until we built one, tested and played it, is that decoupling the coils magnetically is a fundamentally more efficient way to do it. The same way that removal of the pole piece caps improves Q, magnetic decoupling of the coils results in a similar “improvement”.

Add all of these benefits up and it enables us to use a less exotic, and also more magnetically permeable, pole piece material in the Z-Series. For instance, the pole piece configuration that sounds like slightly lower Q AlNiCo 3 in the Legacy Series design sounds like higher Q AlNiCo 5 in the Z-Series format. And, in relation to the efficiency gains from increasing pole piece mass discussed earlier, a more magnetically permeable pole piece allows us to get higher output at even lower resistance. So much so that the “vintage” output Z-Series models have similar or even lower resistance than their conventional counterparts. A significant implication of this efficiency gain is that these vintage output models are totally compatible with, in fact optimized for, 250 kΩ potentiometers. You can just drop them into your existing controls!

We will be officially introducing Zexcoil Z-Series pickups very soon.

Appendix – A brief discussion of “Q”

The parameter “Q”, or the quality factor, is used in many branches of physics. In a general sense, Q is a measure of the energy stored in a system compared to the energy lost by the system in a given cycle. For an oscillator, a high Q means the oscillator will ring for a long time. For a mechanical system, like a pendulum, a high Q means the pendulum will swing for a long time. Systems with higher Q can generally be thought of as more efficient since they make better use of the energy that is input to them. For an inductor, like a guitar pickup, Q is a function of frequency. The most convenient definition of Q for a guitar pickup is taken at the resonant frequency. The Figure below shows how Q at resonance is calculated from a plot of impedance versus frequency for a guitar pickup. So for a guitar pickup, a taller, narrower resonant peak is indicative of higher Q.