Volume and tone control of a modern stereo complex. Encyclopedia of radio electronics and electrical engineering

Encyclopedia of radio electronics and electrical engineering / Tone, volume controls

 Comments on the article

The sensitivity of the human ear noticeably depends on the frequency, which is clearly seen from the curves of equal loudness in Fig.1.

Ris.1

To ensure high quality reproduction over the entire volume range, it is necessary to compensate for the corresponding differences in hearing sensitivity. Currently, this problem is solved with the help of volume controls with loudness close to optimal.

Many radio amateurs involved in the design of high-quality equipment know how difficult it is sometimes to find a variable resistor with taps for a thinly compensated volume control.

Meanwhile, there are several ways to use ordinary resistors for loudness compensation [2], [3].

The controller described in [2] is taken as the basis of the proposed controller (Fig. 4).

Fig.2 (click to enlarge)

In order to obtain the maximum signal-to-noise ratio at low volume, the tone block on a low-noise microcircuit is first turned on and only then the volume control.

The rise of the frequency response at frequencies below 300 Hz with a slope of 6 dB / oct. define elements of environmental protection R28,C10.

Knee frequency f=1/2-R28C10

The rise in frequency response at frequencies below 100 Hz corresponds to 12 dB / oct., due to the additional action of the circuit R23, C8. The R20C7 circuit helps limit the rise in frequency response at frequencies below 20 Hz. The rise in frequency response at frequencies above f=l/-RC 8 kHz is limited by resistor R25 at 10 dB.

If you need a sharp decrease in volume ("intimate" effect), switch S2 is provided. At the same time, the effect of thin-pension remains practically unchanged. With the same switch, it is advisable to change the sensitivity of the power level indicator.

Out of compensation for almost all schemes remain frequencies in the region of 3...4 kHz, requiring a cutoff from 4 to 8 dB over the entire range of volume changes in a narrow frequency band, as well as frequencies of 12...16 kHz near the edge of audibility, requiring their steep rise .

Taking into account the high level of the other links of the stereo complex (players, tape recorders, tuners, etc.), i.e. having a flat frequency response over the entire sound range, for tone control, as a rule, a two-band tone control is enough.

The circuit of the amplifier "Arktur-001" [5] was taken as the basis for the development. In addition to adjusting the tone in the regulator, the signal is amplified three times. This decision made it possible to abandon the normalizing amplifier.

In order to eliminate the above disadvantages of a thinly compensated volume control, a third tone control at a frequency of 3,5 kHz was introduced, with which you can get the effect of "presence" by setting the desired rise in the frequency response, as well as more complete compensation by attenuating the signal by 4 - 5 dB. For the same purpose, an inductance was introduced into the RF regulator, which contributes to a steeper rise in the frequency response at a resonance frequency of about 15 kHz.

Taking into account the difficulties with ferrite rings (their shortage and the complexity of winding), the inductance of the mid-frequency controller is made on a transistor equivalent - a gyrator. The operation of such a gyrator is described in detail in [6].

The regulators are fed from a bipolar stabilized source with a voltage of + 15V through RC filters 100 Ohm, 100 uF (not shown in the diagram).

The equalizer can be used as a non-inertia noise suppressor [7] in the tape recorder path, making a recording with a midrange rise of about 5 - 6 dB and, accordingly, playback with the same blockage. In this case, the noise reduction will be approximately the same 5 - 6 dB.

The resonance frequency of the MF is calculated by the formula

Fo=1/2-(R6R10C3C4)1/2,

where resistors are in kΩ, capacitors are in uF, frequency is in kHz.

Substituting the values ​​in the formula, we get:

Fo=4 kHz

The quality factor of the resonant circuit is equal to two. With C4 equal to 2700 pF, the resonance frequency is 3,5 kHz.

All five variable resistors are of the SPZ-33-23P group A type, which are soldered directly into the boards. The volume control is made on a separate board. All electrolytic capacitors are K50-35, the rest are K73-17 or KM-56. Fixed resistors of type C2-23 or MLT with a power of 0,125 W. The inductor is wound on a 2000NM K18x5x5mm ring and contains 100 turns of PEL-1 0,27 wire. Instead of an equivalent inductance (elements R6, RIO, R11, C4, VT1), between points A and B, you can turn on an inductance of 60 MH, 250 turns of PEL-1 0,18 wire on the same ring. In this case, the capacitor C3 with a capacity of 0,01 μF must be replaced with 0,033 μF.

In the absence of rings, the inductance L1 can be completely eliminated, while the rise of the RF components of the signal will be in a wider frequency band.

References:

1. M. Sapozhkov. "Electroacoustics", M, 1978.
2. A.S. No. 1185573 publ-126-86 p.9
3. S. Fedichkin. "Loosely compensated volume control" "Radio" No. 9/84 p.43,44
4. N. Sukhov and others. "Technique of high-quality sound reproduction". Kyiv. Technique. 1985 p.27.
5. A. Vorontsov, V. Voronov. "Arcturus-001-stereo". Radio No. 1 / 77, p. 34 - 37
6. L. Stasenko. "Multiband with analogues of LC filters" "Radio" No. 10/79 p.26 - 27
7. N. Sukhov. "Inertial noise suppressor". "Radio" No. 2/83, p.50.

Author: A.I.Shikhatov

See other articles Section Tone, volume controls.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

Alcohol content of warm beer 07.05.2024

Beer, as one of the most common alcoholic drinks, has its own unique taste, which can change depending on the temperature of consumption. A new study by an international team of scientists has found that beer temperature has a significant impact on the perception of alcoholic taste. The study, led by materials scientist Lei Jiang, found that at different temperatures, ethanol and water molecules form different types of clusters, which affects the perception of alcoholic taste. At low temperatures, more pyramid-like clusters form, which reduces the pungency of the "ethanol" taste and makes the drink taste less alcoholic. On the contrary, as the temperature increases, the clusters become more chain-like, resulting in a more pronounced alcoholic taste. This explains why the taste of some alcoholic drinks, such as baijiu, can change depending on temperature. The data obtained opens up new prospects for beverage manufacturers, ... >>

Major risk factor for gambling addiction 07.05.2024

Computer games are becoming an increasingly popular form of entertainment among teenagers, but the associated risk of gaming addiction remains a significant problem. American scientists conducted a study to determine the main factors contributing to this addiction and offer recommendations for its prevention. Over the course of six years, 385 teenagers were followed to find out what factors may predispose them to gambling addiction. The results showed that 90% of study participants were not at risk of addiction, while 10% became gambling addicts. It turned out that the key factor in the onset of gambling addiction is a low level of prosocial behavior. Teenagers with a low level of prosocial behavior do not show interest in the help and support of others, which can lead to a loss of contact with the real world and a deepening dependence on virtual reality offered by computer games. Based on these results, scientists ... >>

Traffic noise delays the growth of chicks 06.05.2024

The sounds that surround us in modern cities are becoming increasingly piercing. However, few people think about how this noise affects the animal world, especially such delicate creatures as chicks that have not yet hatched from their eggs. Recent research is shedding light on this issue, indicating serious consequences for their development and survival. Scientists have found that exposure of zebra diamondback chicks to traffic noise can cause serious disruption to their development. Experiments have shown that noise pollution can significantly delay their hatching, and those chicks that do emerge face a number of health-promoting problems. The researchers also found that the negative effects of noise pollution extend into the adult birds. Reduced chances of reproduction and decreased fertility indicate the long-term effects that traffic noise has on wildlife. The study results highlight the need ... >>

Random news from the Archive A black hole gave birth to a planet 30.09.2017 A strange object emerged from the bowels of a black hole. This was witnessed by scientists from the American space agency NASA. Astronomers were able to see the anomalous behavior of a black hole thanks to the powerful orbital telescope Nuclear Spectroscopic Telescope Array, operating in the X-ray range. An unknown celestial body of enormous size separated from a black hole almost before the eyes of researchers. It is possible that this is a new planet, the birth of a supernova, and maybe some kind of "prisoner" who freed him. For a more accurate answer to the question about the nature of the unknown object, further observations are needed. It has always been believed that the gravitational force of black holes is so great that they "suck" all the objects that are near them. What scientists have seen can completely change all ideas about black holes, said Ohio State University professor Fiona Harrison.

Other interesting news:

▪ New Science - Forensic Seismology

▪ Huawei FreeBuds Pro 2+ headphones with thermometer and heart rate monitor

▪ 1600W chargers with 19" rack version

▪ Electrification of wines

▪ The connection between hunger and curiosity

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the site Encyclopedia of radio electronics and electrical engineering. Article selection

▪ article I did what I could, let those who can do better. Popular expression

▪ article Which animal survived on three ships that sank in World War II? Detailed answer

▪ article Commandant. Job description

▪ article Smoke detector. Encyclopedia of radio electronics and electrical engineering

▪ article Digital tachometer. Encyclopedia of radio electronics and electrical engineering

Leave your comment on this article:

All languages ​​of this page

Arabic	Hebrew	Polish
Bengali	Hindi	Portuguese
Chinese	Italian	Spanish
English	Japanese	Turkish
French	Korean	Ukrainian
German	Malay	Vietnamese

Home page | Library | Articles | Website map | Site Reviews

www.diagram.com.ua
2000-2024