THE ELECTRIC GUITAR IS OUT OF THE ORDINARY

Talking about various musical instruments, it is impossible not to recall the, perhaps, popular and indispensable in modern orchestras and rock bands. Of course, this is the electric guitar.

The history of the acoustic guitar goes back many centuries. No doubt the instrument is very musical and the size is small. Just the thing — it’s too quiet guitar sounds. And if at home, in the circle of friends or tourist volume fire its “voice” is enough, what to say, for example, about the performance of the musician in a large concert hall? In the best case, the sound of his guitar audience will hear only the closest to the stage series.

Masters manufacturing musical instruments, has repeatedly tried to increase the volume of the guitar: did resonating box with a double bottom, increased its dimensions and pin sockets (like what was on the old gramophones). However, all these tricks gave only minor results.

Only in the early twenties of our century, invented an effective way to increase the volume of the guitar. Using a special transducer pickup published instrument sounds converted into an electrical signal, and reinforced with electro-acoustic system once again turned it into the same sound, but now it is many times louder.

Initially musicians used a variety of pickups. For example, the most simple of them — a conventional microphone. It is placed inside a resonant box and with the cord connected to the low frequency amplifier. Did the pickups and on the basis of piezoelectric elements. In such constructions, the piezoelectric element was attached to the deck and transformed into electrical signal mechanical vibrations, and resonate with the sound vibrations of the strings. Invented other ways of elektrifizierung acoustic guitar. However, they all remained very imperfect. The fact that perceiving sound vibrations the pickups sensitive not only to the useful signals, but also to background noise. Cost accidentally hurt the body and in the “speakers” is heard a zillion times creaking or crackling.

The best results were obtained when I tried to provide a guitar with an electromagnetic pickup (abbreviated ESS). This device creates a string around the magnetic field, responsive to their vibrations. At the same time, this pickup is not very sensitive to vibrations of the soundboard, background noise.

Fig. 1. The principle of operation of the electromagnetic pickup:

1 — constant magnet, 2 — coil, 3 — string guitar, 4 — the magnetic field lines.

Fig. 2. Schematic diagram of the electromagnetic pickup.

Fig. 3. Device sensor pickup:

1 — frame, 2 — core (a permanent magnet), 3 — coil, 4 — base, 5 — conclusions.

How is the electromagnetic guitar pickup, what is the principle of his actions? Suppose that we have a permanent magnet in the form of an elongated cylinder, and over it wound the wire, the ends of which is connected to the input of the amplifier (Fig. 1). Now place this design under one of the metal strings of the guitar. String must be of magnetic material such as steel.

As is known, a permanent magnet creates around itself a magnetic field (Fig. 1 conventionally shows the distribution of its lines of force). While the string is stationary and is directly opposite from the magnet, the whole system is in a state of “equilibrium”, and the output signal of the pickup no.

And now we hit the string, and it performs an oscillatory motion. What happens in this case? Vibrations of a string will lead to deformation of the magnetic field of the pickups. After moving strings, for example, from right to left synchronously with it in different directions will “stretch out” and field lines. This happens due to the magnetic properties of the strings — it’s as though lines of force takes over. While the magnetic flux penetrating the coil changes continuously. Those of you who remember school physics course, immediately realized: an alternating magnetic flux in the coil causes the appearance of the electromotive force. As a result, the input of the amplifier receives the electric signal with a frequency equal to the frequency of the vibrating string. As their attenuation is reduced and the amplitude of the output signal. The same thing will happen if the string oscillates up and down.

It is necessary to note one more feature of the electromagnetic pickup. Because he does not perceive vibrations resonating of the guitar body, the “pure” sound of the strings passed to the amplifier without the participation of the acoustics, it becomes a kind of “electronic” tone.

Fig. 4. Pickup:

1 — sensor, 2 — winding, 3 — core, 4 — base.

Fig. 5. The body of the pickup:

1 — base 2 — cover, 3 — dielectric trim, 4 — hole for connecting cord, 5 — holes for fastening cover to the base, 6 — holes for mounting pickup, 7 — holes for mounting the pickup to the body of the guitar.

Fig. 6. The option to install the pickup:

1 — deck, 2 — latch, 3 — screw, 4 — pickup 5 — nut, 6 — outlet.

We told how the electromagnetic pickup for the one string. Now imagine that we made such coil magnets for each of the six strings of the guitar, combined the findings of the coils in series, and the free ends connected to a powerful amplifier. And what — we got a real guitar with electromagnetic pickups.

By the way, the design EMSS, which we were told was not unique. Sometimes doing just one pickup, common to all strings. To do this, take a flat elongated magnet, and a coil wound over its ends.

Over time, the guitar lost much of what at first was like its acoustic predecessor. First, the musicians refused resonating box — now it was not needed. The guitar has become much thinner, and also lost the socket — hole in the center of the body. Then, trying to give the new tool a little more originality, began to change the shape of the neck, body, their color. On deck appeared guitar pickups, a variety of mechanical clamps, vibrators, volume controls and tone controls. So the guitar gained its new “electric” appearance.

On modern electric guitars set of electromagnetic pickups, but the tools themselves are diverse. There are the usual six-string and twelve strings — this tool allows you to “juicy” is rich in harmonics sound. There are electric guitars with a short neck — from them we can extract the sounds are very high pitched. There are even electric guitars with two necks — one of them has six strings, and the other twelve. Finally, it should be said of such an instrument as the bass guitar. It has only four strings, but they are much thicker than regular guitar. This instrument, like the bass, sounds the lowest tone.

“Electronic” sound of the modern guitar is not only a result of the lack of acoustic color. Originality to give the sound and a variety of electronic consoles to guitars. For example, the “wow effect” gives the instrument a shimmering, gently trilled sound, and “Leslie”-the system creates the impression that the sound belongs gust of wind, then again approaching. There are other online systems “fuzz-box”, “diston”, “booster”, “vibrato” — the list can continue.

Modern electric guitar — the device is quite complicated. Even the most simple of them is not so easy to make at home — alone mechanical work on making the body and neck are worth! But electrify your acoustic guitar without too much difficulty. How? Will tell you more about that.

Schematic diagram of the electromagnetic pickup for acoustic guitar shown in figure 2. As you can see, it consists of six series-connected sensors L1—L6 (one for each string), which is an inductor with permanent magnets as the cores. With the input of the amplifier the pickup is connected by means of shielded wires with plug ХР1 at the end.

The sensor (Fig. 3) consists of a cylindrical frame with internal Ø 2 mm and height 15 mm, diameter 10 mm, cheeks (made of cardboard or heavy paper), on which is wound bulk wire sew or PEL 0,075—0,1 to fill the frame winding. Inside the frame is inserted a permanent magnet Ø 2 mm, length about 18 mm. it will fit any ready, for example, the magnetic letters of the alphabet. Each sensor is glued to the base — Board with a thickness of 1-2 mm, cut from fiberglass. For greater strength the magnet will secure it in the hole previously made in the Board.

The design of the cartridge in the assembled condition shown in Fig. 4. The distance between the centerlines of the sensors must be equal to the spacing between strings (indicated by the letter d). Board dimensions-base is 6—7dx20 mm. At the edges of the base and drill four holes Ø 2.5 mm. Conclusions sensors connect according to the schematic diagram, and to the free ends of the pickup podaite shielded cord, for example, from a household radio.

If the clearance between the strings of the guitar to the pickups of less than 10 mm, the sensors can be positioned on the base in “chess” order.

The body of the cartridge, made up of the base and cover, make from a sheet of aluminum about 1 mm thick (Fig. 5). Its dimensions depend on the dimensions of the pickup, so the exact data we do not specify. The base is made of eight holes: two for attachment of the top cover have an internal thread M2, two for fixing to the body of the guitar and four to set up the Board with the sensors. Top cover, in addition to the two mounting holes Ø 2.5—3 mm, has another for a connecting cord. In addition, at the top of the cover cut a window size of about 5,5dx10 mm, is closed by a dielectric plate, for example, of thin colored or frosted Plexiglas. Hole it is necessary that the metal casing is not screened concentrated around the sensors magnetic field. The top cover of the cartridge, it is desirable to paste over with a film “under the tree”.

Collect EMSS in the following order. Mount the sensors and pripal to them connecting cord, install the cartridge on the base and secure with four screws with countersunk heads and nuts. The shielding braid of the cord it is desirable to combine with a metal base — in this case, the body will act as a shield, protecting the pickup from interference. Then the connecting cord thread specifically for him, the hole in the top cover and install it on the bottom of the case so that both sides of the petal with the holes to mount the cover was inside. Two screws secure the cover to the free end of the connecting cord solder the plug to connect the guitar to the amplifier.

Now we have to fix the pickup on the sound box of the guitar — it is best to install it in the plug hole. From a piece of rubber with a thickness of 8-10 mm manufacture two clamps of a width of 10 mm (can use ordinary pencil erasers). Length of clamps depends on the diameter of the outlet and the dimensions of the housing of the cartridge. Their profile is shown in figure 6 by means of two screws with nuts the retainers are attached to the pickup. Due to the elasticity of rubber all design effortlessly installed in the socket body of the guitar. Furthermore, the clips act as shock absorbers, preventing unpleasant to hear the chatter of the deck resulting from resonance phenomena.

Assembling an electric guitar, remember that it will sound louder the closer to the strings you place the pickup. But do not overdo it, otherwise the strings will touch his body. Pay attention to the location of the sensors EMSS. Their centerline shall be located strictly in front of the strings depends on the sound quality of the instrument. And of course, show the accuracy and care so that the pickup turned out small and fits in the socket of a guitar.

After Assembly of the electric guitar can be connected to the amplifier. If you do not use the amplifier, player, recorder, radio, or gather in one of the schemes published in our journal.

V. ANCEV

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