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    On another board I had posted an article summarizing and detailing the amazing work of about a dozen people in creating a unique guitar pickup.  That article was removed along with dozens of other valuable articles because of a severe misunderstanding on the part of a few people, tempers flaring, and angry reactions rather than calm solutions.

    I can't do anything about that situation or the people and attitudes behind it... but I can restore this bit of knowledge to the Handmade Music community. Although I no longer have the names of the people originally involved in this project, to the best of my ability, following is a re-creation of the original article.


    The term induction pickup is simple way to say "transference of electricity".  The concept is simple: 

    1. Ferrous guitar strings (steel or nickel or chrome) disrupt the pickup's magnetic field.

    2. Copper within that field converts the energy generated into micro-voltage.

    3. A pass-through or step-up micro-transformer reduces amperage and increases voltage to a level that can be recognized and increased by a guitar amplifier.

    No battery or external power source of any kind is required, nor is a large coil required.  The only coil exists within the transformer and it is very small, largely impervious to RF or EM interference.  That fact makes the pickup highly resistant to hiss and noise.  It is a "single-coil, clear pickup".  I don't really like to call it a coil, as in my mind one piece of wire soldered to itself forms more of a loop.  So a more accurate name for this may be a "loop induction pickup" or "loop pickup" for short.  Minor technicality and unimportant to the issue that it works. :D

    Following are four different designs detailing how to make a loop pickup.   If you have any questions I can answer them in the comments. 


    Surround a thin bar magnet with a copper wire.  The N/S poles of the magnet need to be on the wide faces. (The above diagram shows "North up" but either pole can face upward.)  Wrap the magnet in packing tape to prevent shorting the wire, then tape it to the wire.  The wire should be a gauge that fits the hole in a pass-through micro-transformer (available on Amazon or Ebay).  The ends of the wire will be soldered near the far end of the magnet prior to assembly, as you do not wish to get the magnet hot.  Use either an industrial soldering iron or pen torch to solder the joint, as the thickness of the wire can be tricky to solder.  

    The side diagram shows how the wire passes down through the lid to the interior of the box.  You can use any micro transformer you wish;  I've tried several different kinds of varying types and strengths... and they all sound good.   Since sound is subjective, some may prefer one transformer over another.

    The wires run to the volume control, just as with a normal pickup.  If you wish, you can bend the thick copper wire so that the transformer sits underneath the magnet / wire area.


METHOD #2:  4-prong Transformer

    This is made similarly to method #1 but rather than using a pass-through transformer, uses a step-up transformer (4 poles, 2-in 2-out).  The large copper wire attaches to the two input poles.  Guitar wire runs from the two output poles to the volume control.  Other than that the concept is the same.


Method #3:  Full wire pass-through transformer

    With this method a copper loop on a thin wood backing surrounds disc magnets. (Alternately you can use a bar magnet as in the prior two methods.)  The magnets are insulated by tape as before.  The copper wire is soldered at one end (or a side) prior to installation.  The other end of the wire runs into a pass-through transformer with a large hole in the center, allowing both sides of the wire to run through the same hole.  This creates current as the wire runs in and out of the transformer.   The transformer itself is quite a bit blockier, but can be made of items such as disassembled power adapters (wall warts) with satisfying results.  This is the "scavenged and found" parts version of an induction pickup and would work well on a steampunk-themed git.


Method #4:  Plate Diagram

    Unlike the others, this is made from an aluminum or copper plate rather than copper wire.  This is a bit more time-consuming to build but offers a different sound.   In this design the plate is cut part way up the middle (to the end of the magnet) to separate sides of the plate, in effect creating a C-shape loop.  It is then bent so that the end of it drops down and underneath the box lid. (Alternately you can leave it flat and have the whole thing showing above the box, with only the transformer itself hidden below the lid.) 

    The tape-insulated bar magnet can be put on the top or bottom of the plate (I recommend on top).  Two bolts and nuts run down through the sides of the plate and clamp a copper wire, which runs through a pass-through transformer as used in the first diagram.   The wire from the transformer runs to the volume control.


    As can be seen in all of these methods, the basic principle is the same:   surround the magnet with a copper or aluminum loop,  which converts the magnetic distortion field to voltage, increases that voltage at the micro-transformer and sends it out to your amplifier. 

    The result is a pickup that produces crystal clear, noise-free and hum-free sound.  Just about anyone can make these; the designs are public-domain.   They are relatively easy to build once you have collected the parts.   Note that compared to other pickups these are relatively low-volume and don't have the rich body of other pickups.  These are clean-signal without distortion or typical noise issues.


    PS:   It has been claimed that this design was invented years before, but evidently was never marketed.  Kudos to the original genius of designing it... but that is of historic interest and for some reason never became widespread or in general use.   This post documents the work of a group of individuals flying by the seat of our pants and figuring out one step at a time how to make a different kind of pickup that would be easier to build than standard pickups.  The effort took some 95+ pages of research, documentation, discussion and experimentation, then was continued on 15+ pages of a second thread.   The resulting designs are what you see above, are public domain for anyone to use, is fully documented above, and can be built and/or sold by anyone who so desires, without restriction from anyone-- which is as things should be in the field of cigar box guitars. 

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Thanks for sharing.

You bet Jim.  Any questions about how these work not posted above, I'll be happy to answer if I know it.

WOW Wayfinder, lots of cool info to consider here.  Thanks!

About a decade ago when I was doing a lot of experiments with pickups I came up with a very simple idea which worked as a proof of concept.  I didn't pursue it much because of my workload.  The concept is a simple one to test, all you need is a test lead with a 1/4" jack on one end & 2 alligator clips on the other and a magnet. 

Attach the clips to a guitar string on each far end of the nut and bridge, plug into an amp and hold the magnet near the string.  That's it.  I was able to get a signal to the amp.  It wasn't very strong, but audible when the amp was turned up.  My VERY STRONG charging magnets worked much better.  After that test I built a prototype with 2 strong neo bar magnets glued under the string near the nut and bridge.  I made a diddley bow, buried one wire under the fingerboard and attached to a brass nut.  The other wire was attached to a brass bridge.  Both (hidden) wires ran to the jack.

It worked!  Here it is:

Let me know your results if you decide to test this.

That's very interesting Ted.  We actually discussed that possibility in the original thread (since the string itself is somewhat in the form of a wound coil), but no one tested it.  We wondered how it would react when the slide was run up and down the string.  Did it retain proper tone and sufficient volume?

If it did... add a step-up micro transformer to that setup and voila!  :D

Ted, could we get a closer look at that nut and bridge setup.  Not sure what you did there.  If I get a chance to test and verify, will be happy to do so.  Looks like a nice short project and a lot of fun.  I'll enjoy hearing the results.

Sorry WAY, no pics.  But the concept couldn't be simpler.  Each end of the string is attached to the jack, a magnet is placed nearby and the output sounds like the guitar string(s).  The simple way to explain it is that 

Sounds good.   So we run a wire from both ends of the string to a guitar jack, put a magnet underneath the string.  I have got to try this... find out the best position for the magnet, if adding a transformer increases the volume, etc.   Can't resist one like this.   Thanks Ted!  Whole new kinda Diddley Bow!  :D

I  tried  that Ted a few years ago when you 1st told me, it works ok but it is hard to make music, as your slide or fret reads in both directions to the nut and bridge, resulting in 2 tones, but it definitely works as a pick up
Ted Crocker said:

Sorry WAY, no pics.  But the concept couldn't be simpler.  Each end of the string is attached to the jack, a magnet is placed nearby and the output sounds like the guitar string(s).  The simple way to explain it is that 

Hmmm... resulting in 2 tones eh?  That actually sounds interesting.  : )

Gotta get off my tail and try this.  Will take what, 30 minutes or so to make a test run of one of these, maybe an hour.   And I definitely have lots of low-E strings sitting around. :D

Darryl, that only happens when you have a magnet near the nut, it picks up both sides of the string when fretted or with slide. Some interesting sounds...

I finally got around to making one of these. First pic shows initial try, in a wood frame to hold it above the strings. The pic does not show the packing tape between the copper wire and magnet. Success. The second pic shows the next two iterations actually installed in the box. The first is thin copper sheet, with the magnet (scavenged from a computer hard drive) underneath. The screws not only hold the assembly to the top but serve as attachment of another copper strip running through the coil. The last is a version I'm working on to make it a little prettier with the copper cut out to show the magnet.  Cheers!

Re-reading this Ted... do the sounds come out harmonic or discordant with 2 magnets?   I'm guess discordant, but figured I'd ask.   One magnet is enough of course, but you know how it is... that curiosity factor. :D

Ted Crocker said:

Darryl, that only happens when you have a magnet near the nut, it picks up both sides of the string when fretted or with slide. Some interesting sounds...

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