Kit 26: Mini Electric Guitar


If you’re not a musician, or you slept through your physics classes, here’s a quick run down on guitars. First, take something that isn’t overly elastic or stretchy and fix it to two end posts, such as a steel wire, twisted horse hair or cat gut. Tighten the string down (generally by wrapping the ends around the posts and then turning one of the posts for adjustment). Now, pluck the string and it will vibrate at a frequency based on the tension and length of the string. This vibration moves the surrounding air to create sound waves of the same frequency as the string. If you mount the entire assembly on a wooden box, the cavity of the box acts as a resonator to amplify and direct the sound, as well as to create complex harmonics (integer multiples of the sound waves) that “add richness” to the sound. The more strings you have, the more notes that can be played at one time; and frets under the strings give you a wider variety of notes from the same string, reducing the number of strings you need for the sound range.

With an acoustic guitar, the body is placed under the general playing area, and the neck is added to allow for longer strings. Expect 6 strings on most regular guitars; 4 on bass guitars. All pretty basic and simple – it’s the crafting of the guitar that takes all the work, and the tuning of the strings that requires practice. Of course, knowing where to place your fingers for different chords also helps.

All of this goes out the window when we convert over to electric. The body becomes a solid sheet (wood or plastic), you can have multiple necks, and the shape of the guitar has little effect on the sound produced. In fact, the sound is made by using a coil (pick-up), located under the steel strings, and then feeding the electrical signal generated in the coil from the vibrating strings, through an amplifier or various processors before running it out to an external mixer and/or speaker. All that really remains the same from a physics viewpoint is the vibration of the strings and where you put your fingers along the frets.

Gakken kit #26, The Mini Electric Guitar (3400 yen), is a continuation of the SX-150 synth and wire recorder kits, in that the circuit boards are preassembled and that there’s not as much eye-hand coordination required for assembly. That, and the price tag has jumped again. Kit 1, the putt putt boat was 1600 yen, and now we’re consistently up at around 3400 yen per kit (#27, the 8-bit microprocessor will also be around this price). The book suggests an assembly time of 1 hour, and it took me about 1 and 3/4 hours because I was being careful and rereading the instructions multiple times before proceeding. There’s about 20 pieces, including the wires and screws. The body is about 15″ long and 5″ wide when fully assembled, and it’s got 4 strings.

For the most part, assembly is fairly straightforward (PDF instructions here). The tricky parts are in installing the strings and putting together the pickup coil. The book has a warning about uncoiling the strings, which is important because they unwrap really fast and can swipe you in the face if you’re not careful. There’s a small metal rod used for mounting the strings, and you want them in order from thinnest to fattest, with the fattest wire on top when holding the guitar for normal play. Run the strings from the back of the guitar up to the tuning pegs, then from the bottom of the guitar up over the end of the neck and back down to the 4 mounting screws. Be careful as you wrap the strings around the screws – you want to pick up most of the slack at this point, but if you use a pliers to hold the strings, you can damage them. Wrap the strings around the screws about 3 or 4 turns, then tighten down the screws to hold the strings in place. (Any excess wire can be concealed within the guitar body when you put the covers on.)

As for the coil, start by running the copper wire through one of the small holes in the coil form, get about 2-3 inches of slack wire and tape it down with cellophane tape onto the form, then bolt the form to the guitar body as shown in the book. Wrap the wire around the form, making sure to avoid kinks and snarls, until there’s about 2-3 inches left. Run the loose end through the mounting holes in the form, take the tape off the other end and run that end through the other hole as well (again, as shown in the book). When you wrap the copper wires to the leads for the plug end, make sure that the uninsulated parts of the wires make contact as you twist them together. Use cellophane or electrical tape for insulation and don’t let the two wires from the coil short out against each other. Finally, wrap a thin strip of cellophane or electrical tape along the coil to protect the copper wires. It doesn’t matter which ends of the coil are connected to the red and black wires of the connector jack, but you do want the red and black wires running down to the guitar body, rather than aiming up at the strings, when you wrap up the coil with the long strip of tape (see photo below).

After the coil is finished, put the magnet inside coil form, peel the paper off the one side of the silver seal (the rounded silver shape with the 4 holes) and put the seal on the top of the form to hold the magnet in place. Try to center the seal on the form as best you can (although, it’s not critical). Unbolt the coil from the body and mount it into place under the strings. Line it up so the holes of the seal are centered under each of the four strings (this is critical) and tighten the mounting screws down to fix the coil in place. When you screw down the amplifier circuit board inside the guitar body, make sure that you don’t pinch the wires between the posts and the screws.


(Close-up of the pick-up coil and wiring. Note the cellophane tape wrapped around the outside of the coil to protect the copper wire and hold it in place. Note also how the red wire comes off the coil at the top, above the tape, and threatens to touch the guitar strings. You don’t want to do this. You want the red and black wires to come off the coil from the side away from the strings. Note also the silver seal with the 4 holes, which holds the magnet inside the coil form. You want the holes to be centered under the strings.)

The kit uses two AA batteries. It has an internal amplifier and speaker, plus a big audio jack for plugging into an external mixer or amp. The tuning pegs at the bottom can be tightened or loosened as needed to tune the strings. Like a true electric guitar, the mini has a raw noise sound when you hit all of the strings at one time. To make it sound better, you’re going to need to be very careful about the tuning. I’m not a guitar player, so when someone I know tried to tune the mini, he gave up saying that the strings haven’t stretched out yet so the thing won’t stay tuned; I pretty much have to trust him on that. I do know that the positioning of the seal under the strings makes a big difference. If the holes aren’t centered under the strings, then one string is going to be interpreted as being two strings at one time, and one of those “interpreted strings” is going to sound horribly out of tune.

The output from the guitar jack is not enough to drive iPod earbuds. I did use a small external speaker, which worked but was very hissy. I don’t have a mixer or good amp yet, so I can’t say anything about the final sound output. All the comments I’ve gotten so far have just been that the mini looks like some kind of little ukulele.

The mook is great, though. It starts out with profiles of various Japanese guitarists (Sugizo, Scandal, Shonen Knife), and includes write ups of the axes that they posed with. There’s a piece on converting the mini to a Hawaiian steel guitar sound, and some sheet music at the back for Smoke on the Water and Silent Night. There’s a long piece on the history of electric guitars, from the original banjo/frying pan shape in the 1930’s, up through Jimmy Hendricks, Led Zeppelin, the Ventures and AC-DC. There are a lot of pictures of unusual axes, like Cheap Trick’s 5-neck monster, and a story on a Japanese artist that does custom paint jobs. Mods include putting the mini into a wooden shell, turning it into a steam punk pistol, and adding a smoke gun and electric light effect. Then there’s the 2 pages of effects pedals (wah-wah, distortion, etc.), examples of weird customized guitars (including a collapsible version and a 2-string shamisen) and instructions on how to learn to play the mini. There’s an article on a guy that makes life-like models of insects using tissue paper and paint, and a manga explaining why body odor makes you stink bad. I’m not sure about the Koress Project story, but it looks like a circuit board that allows you to control appliances via twitter tweets. Probably the best story is on the ex-Megadeth member who’s “gone native” in Japan – Marty Friedman. If you like Megadeth.

Musicians mentioned in the mook:
Tomoyasu Hotei (Bambina is HOT! But I like Karasu better).
Kazumi Watanabe (You Can Do It, and Nothing from Nothing)
Kotaro Oshio (Canon-Kanon, and Fantasy!)
Kyoji Yamamoto (James in my Casket, and Hurricane)
Sugizo (Enola Gay, and 1000 Knives)
Shonen Knife (Top of the World, and Twist Barbie)
Scandal (Don’t Say “Lazy”, and 09, 09, 26)
Yoshio Nomura (Rider Chips main page, Nomura’s Official Page) (Surreal is good)
Marty Friedman (Solo piece, and Tornado of Souls)

I’ve got to say, that if you think Japanese rock is dead, there’s got to be at least one video up there that’ll change your mind (assuming that youtube hasn’t banned it due to copyright issues).

Additional Links:
Ukulele Picnic (Hawaiian Guitar site)
Ukulele Duo (Guitar Art)
Pangra (Steam Punk Guitar Gun)
Tokyo Pistol (Graphic Arts site)

Bottom line is that this is a really cool looking kit, but it’s something that’s as hard as the theremin or the SX-150 to make sound good. Not sure about replacement strings, yet, but changing them will require disassembling the body. The mini’s best feature is that it’s small, and can be modded into other shapes. It’s a great introduction to the theory of the machine, and it’s easy to carry around. May be a good toy instrument for kids wanting an addition to their toy piano. (Oddly enough, while there is one photo showing one guy playing the guitar, theremin and synth each, there’s no mention of trying to feed the guitar into the synth; although, there is a suggestion of plugging into the “mike in” jack of your laptop.)

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