|
Arabic
Bengali
Chinese
English
French
German
Hebrew
Hindi
Italian
Japanese
Korean
Malay
Polish
Portuguese
Spanish
Turkish
Ukrainian
Vietnamese|
ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING The sustained sound of an electric guitar. Encyclopedia of radio electronics and electrical engineering
Encyclopedia of radio electronics and electrical engineering / Musician The proposed simple device allows you to make the sound of an electric guitar undamped and get various effects, for example, a sound resembling a cello, an electric guitar recording played back to front (similar to the music of the Beatles), to realize a "soft attack" of sound, etc. The sound of an electric guitar becomes undamped if the signal taken from the pickup and amplified signal is again applied to the strings, i.e., a AF generator is formed, in which the oscillating strings act as a resonator (see figure). One string can vibrate at the frequency of the fundamental tone and at the frequency of the harmonic (overtone), and if two strings sound simultaneously, the beat frequency is allocated, which is formed as a result of the summation of the oscillations. An amplified signal is applied to the strings using an electromagnet YA1, the magnetic circuit of which is a permanent magnet (it is necessary to magnetize the strings). The function of an audio frequency power amplifier (UMZCH) can be performed, for example, by a tape recorder turned on in the "Record" mode; In the experiments, an Astra-207 tape recorder was used (nominal output power 2 W at a load with a resistance of 8 ohms). We can use any other amplifier with a sensitive input and sufficient output power.
The electromagnet YA1 is connected to the output of the amplifier (tape recorder), intended for an external loudspeaker, through the resistor R2, which protects the amplifier from overload. When the X1 plug is connected to the tape recorder, the contacts in the socket open and the internal loudspeaker of the tape recorder is connected to the output of the amplifier through the resistor R1, which serves to additionally control the volume. This is done due to the fact that the amplifier volume control slider is set to a position close to the maximum to ensure generation, and the volume is adjusted by resistor R1. If the effect is not used during the game, the electromagnet is turned off by the SA1 switch. This facilitates the operation of the amplifier, and the permanent magnet is less demagnetized by an alternating magnetic field. XS2 socket and XP2 plug for easy storage. The magnetic core of the coil is a permanent metal magnet with a radial slot and poles at the ends. You can use a magnet from a magnetodielectric (then a cut is not needed) or make a stacked magnetic circuit from ferromagnetic plates isolated from each other, and attach a permanent magnet to one of the ends (which one is selected experimentally). Approximate dimensions of the magnetic circuit - section 27x31 mm, height 32 mm. It cannot be made continuous, since in this case an eddy current will be induced in it, leading to heating of the magnetic circuit and losses. It is desirable that the section of the magnet overlaps several strings, then it is possible to achieve the generation of double sounds and quickly change the sounding string. The winding contains 550 turns of copper enameled wire PEV-2 with a diameter of 0,5 mm, wound round to round. Before winding, the magnetic circuit is wrapped with two layers of thick paper. Coil cheeks can be made of thick cardboard glued in two layers. It is desirable to impose a strip of thin paper on each layer, then the winding is even. The finished coil is wrapped with insulating material (for example, electrical tape), which, for reliability, is fixed with a strong thread. The coil is connected to the XP2 plug with a flexible shielded wire in insulation about 2 m long. The places where the wire is soldered to the coil should be insulated. XS2 socket and XP2 plug - any small-sized socket, for example, for miniature headphones. Variable resistor - PPZ-41 or any other type with a rated dissipation power of at least 1 W, fixed resistor - MLT-2. Switch SA1 - any, the main thing is that it be reliable. You can use the switch for open wiring by placing resistors in its housing. The handle of the resistor R1 engine and the XS2 socket are brought to the side wall. In order for the variable resistor to fit in the case, the base of the switch is slightly filed with a file. The wires with which the parts placed in the case are connected to the output of the amplifier should be as short as possible. The wire that connects the guitar to the sensitive input of the amplifier (the microphone input of the tape recorder) must be shielded to reduce the level of interference. If the guitar has electromagnetic pickups, when checking its performance, first turn on the one that is closer to the tailpiece. The guitar signal level and amplifier sensitivity controls (recording level in the tape recorder) are set to the maximum position; the slider of the resistor R1 - to the position of maximum resistance (to the right according to the diagram). Switch SA1 closes the circuit. The coil is brought end-to-end to the strings at a distance of 0,5 ... 3 cm and the amplifier volume control is used to achieve generation, for this the string is plucked. In a guitar with electromagnetic pickups, an inductive connection is formed between the electromagnet and the included pickups and self-excitation can occur without the participation of the strings: a “howl” will be heard in the dynamic head. In this case, the coil is transferred to the place near the fretboard where, with muted strings, self-excitation does not occur, but if there is no such place, the depth of positive feedback (POS) is reduced along the entire fretboard with the volume control. It can also be reduced by adjusting the signal level on the guitar and the sensitivity of the amplifier (recording level on the tape recorder). If the electromagnet is brought to the neck with the butt end, at a sufficient depth of the POS, a ringing sound with a high level of harmonics (overtones) is generated. And when the POS depth is set even more, generation occurs not at the fundamental frequency, but at the overtone frequency. This sound is facilitated by an inductive feedback circuit between the electromagnet and the pickup: an effect similar to the phenomenon of regeneration in a regenerative radio receiver occurs. In this position, there is a great tendency to self-excitation along the communication chain, so the area on the fretboard where you can play without interference (“howling”) is limited, as a rule, to the first four to twelve frets. If the coil is held sideways to the front of the neck and turned with its end to the strings to generate oscillation, this zone expands. When the electromagnet is held against the strings with the opposite end, a duller sound is generated, with fewer harmonics, although it is also possible to generate overtones by holding the electromagnet near where the string is pressed. In this position, there is no tendency to self-excite without the participation of the strings. If the volume control of the amplifier is set to a sufficient depth of the POS, the sound can occur without strings plucking, from the magnetic field of the coil. In this way, the effect of a "soft attack" of the sound is obtained when the coil is gently brought to the strings. In the "voiced" position, the coils achieve a sound similar to a record of an electric guitar played "back to front", and in the "deaf" position, similar to a cello. The generation of double sounds is less stable than the generation of a single tone. During the game, the electromagnet is held in the right hand, and with the left they play glissando, legato and vibrate the strings. If squeaks occur during the game, it is necessary to reduce the RF level with the tone control of the amplifier or use, if possible, wires with better shielding and shorter length. Please note: if you raise the bass tone control too much and set the amplifier volume control to a very high output signal level, overload may occur, and the resistor R2 will start to overheat (and after it the electromagnet YA1). And one more thing: the coil should not be brought close to the guitar pickups, so as not to weaken the strength of their magnets. Author: A. Branitsky, Minsk, Belarus
Artificial leather for touch emulation
15.04.2024 Petgugu Global cat litter
15.04.2024 The attractiveness of caring men
14.04.2024
▪ Budget microcontrollers Microchip PIC16F152 ▪ Martian soil suitable for life ▪ The brightest fluorescent material
▪ section of the site for those who like to travel - tips for tourists. Article selection ▪ article Lens and glasses. History of invention and production ▪ article The functional composition of JVC TVs. Directory ▪ article Varactor tripler at 430 MHz. Encyclopedia of radio electronics and electrical engineering
Home page | Library | Articles | Website map | Site Reviews
www.diagram.com.ua |
See other articles Section 
Latest news of science and technology, new electronics:
All languages of this page