ZB Pickup In A Standard Wide Mount Format

[Scott Swartz]

I have been trying put the down time to good use, so in addition to practicing I have been doing some pickup experimentation. I have been working on multiple things but one thing I wanted to check out is what would my modern guitar (Williams) sound like with a ZB pickup? My vintage 1969 ZB sounds awesome but the ZB pickup does not fit the modern mounting dimensions.

I have been winding my own pickups for years, so I got some measurements from the ZB and 3D printed a prototype using the two row of magnets / steel baseplate/ center pole pieces ZB design, with the dimensions slightly modified (a bit narrower) to allow for a standard wide mount base plate.

Its wound to the same inductance as my ZB pickup in the middle position (which is what I always use), and the magnetic gauss levels measured at the strings are basically identical as on my ZB so the magnetic circuit is very close. Coil is wax potted to address the microphonic nature that ZB pickups can tend to have.

The tone is definitely similar to the ZB, the guitar itself is different or course, but the silky highs, tight lows, and the fast/precise transient response that ZBs have is there. Its also very quiet for a single coil, same as the ZB pickup is, due to the unique magnetic circuit and how it interacts with the coil.

I attached some pics of the pickup and it mounted on my Williams.

I am now taking orders for these over in For Sale : Amps And Accesories forum here:

https://bb.steelguitarforum.com/viewtopic.php?t=358735

[Dave Zirbel]

Put me down for one...maybe two!

Thanks!
Dz

[Jon Light]

That's slick. Nice job. I could be interested but my Williams is a 12 string. If you got enough 12 stringers expressing interest to consider doing it, there's also the question of string spacing. My Williams is considerably tighter than my Fessenden, (is that just a 12 string thing or are the 10 stringers tighter also?) making my Telonics blade pickup a safer choice.
That said, I'm always able to get my head turned by a new pickup. Consider my head turned.

[Bob Hamilton]

I'd take a couple of those Scott

[Scott Swartz]

Thanks for the interest guys, and I would like to address string spacing as Jon Light brought up, and also wide / narrow.

I have heard from the ShoBud ShowPro side of the steel guitar world via PM that there is interest in a narrow mount version, which is no problem, however these steels also use a bit wider string spacing.

The prototype in the pic is 75 mm or 2.95 low string to high string center to center, measured at the pole piece screws. In addition to what the difference may be at the changer, different brands have different tapers to the keyhead, complicating it further. The 75 mm is dead on for a Williams but might be slightly narrow for most other brands?

ShoBud Show Pro needs something more like 80 mm or 3.15 and narrow mount of course.

Would a 77 mm (3.03 inch) wide mount and a 80 mm (3.15 inch) narrow mount cover everyone's needs? I could also add a 12 string versions at 91 mm (3.59 inch) wide, would that split the difference between Williams and the brands that are a bit wider?

[Bob Hamilton]

3.03 would work for me.

[Jon Light]

91mm is dead-on for my Williams 12 (wide mount).

When you get to being ready to consider production and quote prices, I am watching with interest.
I was very surprised to read that this is a single coil pickup. I'd always assumed that there was hum cancelling going on with all those rows of...stuff. I am a committed humbucker user. But I did read your observation re: noise.

For 'data base' information, the Fessenden 12 is around 94mm. I've never known how sensitive, how important pole-to-string alignment is.
This picture of a BL 712 with my Williams just doesn't look like it would work well. Does BL also offer different spacing? Just wondering out loud. Don't mean to hijack.

[Scott Swartz]

Jon,

The easiest way to think of the ZB style pickup is "noise rejection" due to the very tight magnetic circuit.

As opposed to "noise cancellation" as in dual coil pickups with two opposite current (wound) coils.

There are guitar single coils that are known to be quieter via the same principle such as gold foils, hilotrons, and Fender Jaguar. The patent for the Jaguar pickup discusses it a little bit, US patent 3236930.

[Dave Zirbel]

Does the prototype have the same spacing as the zb original? That works for me. Thanks for doing this!

[Scott Swartz]

Dave,

My 1969 ZB pickup is 77.5 mm spacing, so the 77 mm option I am offering is extremely close. The "77" is actually 77.22 mm in the CAD software based upon how I divided the 9 spaces into an xx.xx millimeter resolution in the software.

[Dave Zirbel]

That should work...my zb pickup didn't even match the string spacing perfectly on my zb....and sounded just fine!

[Ross Shafer]

Great Job Scott, these look nice! Zirbman is one of Sierra's test pilots so I look forward to his opinion. It'd be awesome to have a new single coil source!

[Dave Zirbel]

Great Job Scott, these look nice! Zirbman is one of Sierra's test pilots so I look forward to his opinion. It'd be awesome to have a new single coil source!

I actually have an original zb pickup with triple coil tap that looks like it will fit the Sierra...I may throw that in this weekend. Stay tuned!

[Stu Schulman]

Scott,I would like a 10 string wide mount in white for my Desert Rose keyless, Send me a PayPal thingy
sturoomers@gmail.com

[Eric Dahlhoff]

Scott,
I've always been curious about what's inside a ZB pickup. Do you have a picture or diagram you could share?
What are those extra rows of thingys? Magnets? Does the coil loop around the center row of poles and also the outer ones?
Thanks, Eric

[Scott Swartz]

The coil is just around the center polepieces, and the two row are magnets. The creates a North South North magnetic pattern and a very even gauss at the strings across a long length of string

[Matt Sutton]

Hi Scott-
Joining the chorus here- I'd be interested in a triple tap one to go into my 70's Fender/Bud. Great instrument mechanically, but I've been spoiled by the sound and response of my ZB.

Also: Going to be doing a teardown/cleaning of the C6 changer on my ZB soon. Its very early (#1008), so let me know if there's any measurements, images, etc, regarding the PU that would be useful to you in your work.

[Scott Swartz]

Matt, Based on the smaller space available in wide or narrow mount format and my wiring method i am only doing single tap, but I can wind that to whatever you might want. I have posted a lot of additional info over in the But Sell Amps Accessories thread.

The resistance readings on you ZB pickup would be interesting to know.

[Eric Dahlhoff]

Here are resistance readings I've taken on ZB's I've owned. Seem to be all over the map! There are 10/11/12 strings, so that makes a difference too.

[Scott Swartz]

The readings do vary some but there are some generalities that are constant. The resistance is approximately doubling between low and mid on most, and then a factor of 1.7-1.8 from mid to high.

This matches the logic of the readings from my ZB:

Low Setting R = 6.26 K-Ohm L = 1.49 Henries (1/2 the inductance of a strat pickup!)

Mid Setting R = 13.57 K-Ohm L = 6.61 Henries

High Setting R = 23.80 K-Ohm L= 19.35 Henries

Inductance varies as the turns squared, so the doubling of resistance from low to high gives 4 times the inductuance, and then it triples mid to high from the 1.7 factor.

Extrapolating from the resistance for the inductance would hold if the wire size is held constant. I have seen posts in the past saying sometime two different gauges were used on the same pickup but none of these readings look like that to me. Also, the high resistances overall indicate either 43 or 44 ga wire, most likely 44 on most of those.

Its also important to note that the tonal balance we perceive does not track only to resistance or inductance, the magnetic circuit plays a part as well. A standard single coil wound for 6.5 Henries would be about 9 or 10 K-Ohms, much lighter than most people use in that design.

[Dave Zirbel]

Hey Scott, just wondering how the steel baseplate affects the zb pickup. Asking because I have a spare zb triple tap pickup without the baseplate.

Super stoked you are making these pickups!

Thanks

[Scott Swartz]

Dave,

The plate provides a low resistance path for the magnetic flux to travel between the bottom of the both rows of magnets across to the bottom of the pole pieces. The steel plate, the steel screws, the magnets, and the string itself themselves have high permeability, which is the measure of this. Put together it creates a low loss magnetic circuit.

This diagram from the Fender Jaguar pickup patent might help, its one magnet and two polepieces but the principle is the same.



Air has low permeability, think about the distance of air the flux lines travel through on a Strat or P90 pickup comparatively.

The ZB pickup will work without the plate no problem, just sound different with the larger air gap for various reasons.

Here is another mindbending thing, the metal is great for the magnetics, but any metal (including alnico magnets) near the the coil simultaneously causes losses in the coil called eddy currents. All pickup designs have to balance these factors.

[Dave Zirbel]

Thank you Scott. I would like to add the steel plate. Would a regular piece of sheet metal work?

Thanks

[Scott Swartz]

Yes you want low carbon, and readily available sheet metal will be low carbon. Galvanized is fine also that won't matter. Thickness, I would recommend 16 or 18 ga ( .060 or .048).

[Dave Zirbel]

Thanks!