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Note: see additional designs in the comments following. For those interested, a link to a finished, marketed version of this pickup concept is available here.
In another thread of some 1,100+ comments and almost 20,000 views, a number of us here on CBN have been brainstorming a viable, reproducible, easily-constructed mag pickup that doesn't involve winding thousands of coils around a bobbin. After quite some time and discussion we have to admit...
Credits to contributors are at the end of this post. Following are photos, parts list and diagrams for construction. Total building time: 15-30 minutes. Versatility: considerable. Sound quality: equal to a standard 6-pole pickup, but more clear and bright with little or no perceptible hum or distortion.
Here are the photos:
We have here a copper wire loop soldered it to two prongs of a 4-prong transformer, with the other 2 prongs leading to a volume control or guitar jack.
The transformer is glued to a block of wood just as an experimental base. It allowed me to clamp the unit to my test-guitar that I use to test all my pickups-- basically strings, tuning keys and bridge on a stick.
I tried this using standard guitar audio wires to lead from the thick copper wire to the transformer-- no good. It seems essential to solder the copper wires directly to the transformer leads to maintain current flow.
I used alligator clips and standard guitar wire to lead from the back two prongs to the jack. No problem there. So we can solder standard wire directly to the output poles.
Volume is excellent. Sound is crystal clear without any buzzing or hum.
I call this community experiment an absolute success. Use something prettier than duct tape as a covering (to hold the magnet between the copper wire) and I would say this is a "finished, usable pickup" of final-stage design. It's fully functional, can be installed as-is through a very small slot in the face of the git (to the side of the neck-through), and the magnet/wire combo can be standard distance from the strings and still deliver good, quality sound.
So on a scale of 1-10 with 1 being "prototype on paper" and 10 being "ready for everyday use"... I'd mark this an 8 or 9. All it needs is the wood block removed and a more attractive covering over the wire and magnet. It is a fully-functional transformer-based pickup. (EDIT: Rate this a 10. I added the decorative covering tonight just before posting this. Looks great. Will post photo later.)
Here are the specs on the device:
Magnet: 2" x 1/4" x 1/16" Neo, N45
Mouser Electronics http://mouser.com
Potted Transformer part #553-CSE187LP
Current Rating: 30 A
Turns Ratio: 1:500
Secondary Resistance: 21 Ohms
Termination Style: Radial
Length: 24 mm
Width: 21.5 mm
Height: 18 mm
Frequency Range: 50 Hz to 400 Hz
Price: $3.91 each + shipping, with quantity discounts. Manufacturer will ship standard 1st class ground if the company is called and special request made. Otherwise it's expedited shipping and a bit pricey.
Note: onsite photo shows non-potted transformer. As the photos above show it is a nicely potted black cube with four prongs. Easy to install. Once a person has this method down I estimate building time 15 minutes. That's pretty awesome for a fully-functional guitar pickup.
QUALITY OF SOUND
This has about the same quality of sound as a regular single 6-pole guitar pickup. It's perhaps a bit more clear and "precise", without any distortion or hum.
At risk of self-promoting (I'm not... just well-acquainted with the product) comparing this to my FlatCat™ pickups... very different. Being humbuckers, FlatCats are far richer and more mellow in tone, as would be expected. I've never heard one of Elmar's pickups, but I can say the same for Dan's: considerably richer and more mellow than the Induction pickup.
So we're looking at a replacement for a standard single 6-pole pickup... but without augmentation it's nowhere near the sound quality of the flat pickups-- nor would it be expected to be since we're comparing a single pole pickup to a thousands-of-winds humbucker. It is brighter and more clear than a 6-pole single, which is a plus.
I have installed these on both CBGs and a 2-pickup 6-string standard electric, and it works great. We have a functional, working, easily-replicated design for a new kind of CBG pickup. Congrats folks.
Note: either the copper wire or the magnet must be insulated. It's fairly easy to wrap clear packing tape around the magnet (or even regular cellophane tape).
We could make a humbucker form of this using one of two methods:
1. Curve the copper wire on around another magnet placed at opposite poles to the existing magnet, then run the wire back down to the transformer. (I believe that would work).
2. Put an identical unit right next to this one with the polarity reversed. I would consider this the superior option as this would allow "coil tapping" as well.
3. Humbucking really isn't necessary as this is "noiseless" tech as it sits. No coil wrap to pick up RFI or EMI... so no need for hum cancellation! To my knowledge, building a "humbucker" would increase power, but offer no advantage otherwise.
We have the technology. We can build it. Congratulations to everyone who contributed to that brainstorm session. Credits will be presented in comments (in alphabetical order) as soon as I can manage.
Be sure to read the comments section for further design information.
THE COMMENTS SECTION!
Edit: it was pointed out a correction was needed in the first comment, and as it couldn't be edited decided to delete it and just add it here. : )
Second version of this pickup: Single coil transformer with pass-through induction.
Third design: Pass-Through Single-Core Transformer Induction Pickup
Darryl's Coil-Through-Transformer design
Buggy's coil-though-transformer design
* Create a copper or aluminum plate with a cut down the middle, leaving one end intact. In the diagram above it's been bent so that part of it can slip under the box face, out of sight. That's just for pretty. In practice the plate can be left straight with a hole cut on the right side for the rest.
* Two holes are drilled in the plate and bolts & double nuts attached for holding a thick copper wire.
* The copper wire is passed through the hole of a 2-lead, center hole specific-strength transformer.
* Leads go from the transformer, either to volume control or straight to jack.
Why it works:
The magnet acts like any magnet does in a pickup. It creates a magnetic field which is disrupted by vibrating strings. The aluminum (or copper) plate acts as a single coil, replacing thousands of wire wraps with one single large-area conduction surface. The electricity flows with extremely low resistance, but very low voltage (far lower than a standard pickup). It is carried by the copper wire through the step-up transformer. That transformer reduces amps and increased volts, to convert the current to a voltage level readable by a guitar amplifier.
That's it in a nutshell. A lot of people have contributed here to this design. It's been tested and proved to work. Basically, a highly unique guitar pickup design produced by our community here. Pretty nifty, eh?
PS. I went through every page of that other thread, and here is a list of the conspirators CONTRIBUTORS to this project, in alphabetical order. I've included folks even if they just posted a one or two helpful entries. Every bit counts. (if I missed anyone, please let me know):
Ron "Oily" Sprague
A tip of the hat to Joseph Rogowski, who many years ago created a similar concept, although he never developed it to market stage and for some reason it didn't become widely known or used. Also acknowledgement to the Lace company who designed and mass-marketed the Alumitone, which although made in a different material, fashion and method, uses similar principles to those developed here on CBN.
An updated, finished and marketed version of this pickup is available here:
Yup. I think it's also likely that with one solid core the current tends to pass through the center (area of least resistance) and less to the outside, whereas with the strands more current is near the transformer coil. The closer the current is to the transformer coil, the better it's utilized. The jump in volume was tremendous.
forgive me a moment while I put on my "Mr. Wizard" hat, hope you like this:
In very high voltage applications such as the long distance power transmission lines up on the giant metal towers with enough juice to not only kill you but reduce your corpse to a smoldering heap, there is enough moving electron charges to push each other to the outer part of a conductor, little to none of the juice travels in the middle. BUT in household voltage (220v, 110v) and lower (git pickups in the 0.1v and below) the juice travels through the conductor uniformly.
Another neat bit is when a conductor carries a current through a ring of ferrous material (a transformer core in this case), it doesn't matter where in the opening it runs through, center or off-center, it transfers the same amount of magnetic field to the core. Like putting a stick of wood through a dowel cutter, it doesn't have to be centered, the dowel that comes out the other end is the same size and the amount of shaving we are harvesting for the furnace is the same. The thicker the primary loop we use, the bigger the magnetic field for the core to harvest from it.
So I'm still sticking to the idea that the reason the stranded 6 gauge 55 amp wire works better than solid is in the solder joint is better. the melted solder runs up in-between the strands touching much more surface area.
That's very interesting. I wasn't aware it didn't matter where the current was in the hole; I was under the impression the closer the current was to the transformer wires the better it would transfer. So... could be a solder thing... although I made sure to solder the solid-wire very well. What one really needs on this is a spot-welder. :D