The simplest booster on transistors can be a good companion for the development of power devices. The circuits and designs are simple; you can independently prepare the device and test its operation, working with all the parameters. Nowadays field-effect transistors can be made from literally three elements into a miniature microphone booster. І connect it to a personal computer to reduce sound recording parameters. The same spіvrozmovniks under the hour of growth will be richer and clearer than your prom.

Frequency characteristics

Low (sound) frequencies are present in almost all everyday devices - music centers, televisions, radios, tape recorders and personal computers. There are also HF boosters on transistors, lamps and microcircuits. The beauty is that the ULF allows you to amplify a signal below the sound frequency that is perceived by the human ear. Sound boosters on transistors allow you to generate signals with frequencies ranging from 20 Hz to 20,000 Hz.

Then, use the simplest device to amplify the signal in this range. Moreover, it should be done as evenly as possible. The strength coefficient depends on the frequency of the input signal. The graph of the occurrence of these quantities is practically a straight line. As soon as a signal with a frequency range is applied to the input of the booster, the efficiency of the robot and the efficiency of the device will change rapidly. ULF cascades are, as a rule, assembled on transistors that operate in the low-mid-frequency ranges.

Class robots of sound boosters

All booster devices are divided into a number of classes, depending on what stage the process flows through the cascade:

1. Class “A” - the stream flows continuously throughout the entire period of operation of the power cascade.
2. In class “B” the flow lasts for half a period.
3. Class "AB" refers to those whose flow flows through the booster cascade for an hour, which is equal to 50-100% of the period.
4. In mode “C” the electric current flows less than half the time of operation.
5. Mode “D” ULF has become stagnant in amateur radio practice quite recently – just over 50 years ago. Most often, these devices are implemented with the protection of digital elements and have a very high efficiency factor - over 90%.

The presence of problems in different classes of low-frequency boosters

The operating area of ​​a class “A” transistor booster is characterized by very few nonlinear effects. Since the input signal generates pulses with a high voltage, this causes the transistors to become saturated. The output signal of the skin harmonics begins to appear (until 10-11). Through this, a metallic sound appears, characteristic of transistor boosters.

In case of unstable life, the output signal has a modeled amplitude relative to the frequency of the threshold. The sound on the left side of the frequency response becomes harsher. Apart from shortening the stabilization of the vitality of the booster, the design of the entire device becomes complex. ULF, which is used in class “A”, has a remarkably low CCD – less than 20%. The reason is that the transistor is constantly open and flows through it steadily.

For advancement (albeit insignificant) the QCD can be accelerated by push-pull circuits. One drawback is that the lines at the output signal become asymmetrical. If you transfer from class “A” to “AB”, non-linear problems increase 3-4 times. But the coefficient of corrosive action in all schemes will still increase. ULF classes “AB” and “B” characterize the increase in noise when the level of the input signal changes. It’s better to add thickness, but it won’t help to avoid any shortages.

Work in intermediate classes

There are a number of different types of skin. For example, the robot class is “A+”. The new transistor at the input (low voltage) is designated as “A”. Any high-voltage voltages that are installed at the output stages are placed either in “B” or “AB”. Such power plants are richly economical and are not in the “A” class. There are noticeably fewer nonlinear problems - no more than 0.003%. You can achieve even better results using vicorist and bipolar transistors. The operating principle behind these elements will be discussed below.

But all the same, there is a large number of high harmonics in the output signal, through which the sound becomes characteristic metal. There are also schemes of support workers that work in the “AA” class. The smell of non-linear components is even less - up to 0.0005%. All the same, the main feature of transistor boosters is the characteristic metallic sound.

"Alternative" designs

It’s impossible to say that they are alternative, but the fachists who are engaged in the design and selection of boosters for the clear creation of sound are increasingly giving priority to tube designs. Tube boosters have the following advantages:

1. The level of nonlinear effects on the output signal is even lower.
2. There are fewer harmonics in transistor designs.

However, there is one great minus that outweighs all the advantages - it is absolutely necessary to install devices for this purpose. On the right, the tube cascade has a very high reference value - several thousand ohms. The input of the speaker windings is 8 or 4 ohms. To please them, it is necessary to install a transformer.

Of course, this is not a great shortcoming - there are also transistor devices that use transformers to serve the output stage and acoustic system. Some experts confirm that the most effective scheme is a hybrid one - in which single-cycle boosters are combined, as long as they are not affected by negative feedback. Moreover, all these cascades function as ULF class “A”. In other words, it will stagnate as if the pressure on the transistor is repeated.

Moreover, the CCD of such devices is high - close to 50%. It’s not easy to focus more on the performance of KKD and tension - not to mention the high intensity of the sound created by the force. Of much greater importance are the linearity of the characteristics and their brightness. Therefore, it is necessary to show respect to us in advance of them, and not to push.

Circuit of a single-ended ULF transistor

The simplest booster, based on the scheme with a carbon emitter, is in class “A”. The vikorist circuit has a conductor element with an n-p-n structure. The collector lancet has a support R3 installed, which encloses the flow that is leaking. The collector connector connects to the positive life wire, and the emitter connects to the negative wire. If there is a combination of feeder transistors with a pnp structure, the circuit will be the same, the axis will only need to change the polarity.

With the help of a separate capacitor C1, it is possible to boost the input variable signal from the constant flow generator. In this case, the condenser is not suitable for passing the exchange stream through the base-emitter path. The internal support for the emitter-base junction together with resistors R1 and R2 is the simplest voltage distributor. Consider resistor R2 to be 1-1.5 kom - the highest typical value for such circuits. With such tension, life continues to flow steadily. If you power the circuit with a voltage of 20 volts, then you can calculate that the value of the power factor of the strum h21 stock is 150. It is necessary to determine that the booster HF on the transistors is connected to similar circuits, just like kiss the little bits differently.

In this case, the voltage of the emitter is higher than 9 and the drop on the “E-B” line is 0.7 V (which is typical for transistors on silicon crystals). If we look at the booster on germanium transistors, then in this case the voltage drop on the “E-B” section is more than 0.3 V. The flow at the collector end is more similar to what flows in the emitter. You can calculate it by dividing the voltage of the emitter on the support R2 - 9V/1 kOhm=9 mA. To calculate the value of the base stream, 9 mA is required to divide the gain factor h21 - 9 mA/150 = 60 μA. In ULF designs, bipolar transistors are used. The principle of work differs from that of the field.

On resistor R1 you can now calculate the drop value - the difference between the base voltage and life. The basis voltage can be explained by the formula - the sum of the indicators of the emitter and the “E-B” transition. With a live voltage of 20 Volts: 20 - 9.7 = 10.3. You can calculate the value of the support R1 = 10.3 V/60 μA = 172 kOhm. The circuit has a C2 capacity, which is necessary for the implementation of the Lancug, where possible the exchangeable storage of the ether flow can take place.

If you do not install capacitor C2, the storage area will no longer be separated. Through this, such an increase in the sound on the transistors will result in a very low amplification factor along the h21 string. It is important to remember that the visceral organs were caught by the equal jets of the base and collector. Moreover, take the stream of the base with the one that flows from the lancug out of the emitter. The fault lies mainly in the supply of voltage to the base of the transistor.

But it is necessary to ensure that along the base lancet absolutely immediately, regardless of the obvious leakage, the flow of the manifold flows obligingly. In circuits with a carbon emitter, the current flow increases at least 150 times. In addition, this value is also insured for the expansion of boosters on Germanium transistors. In some cases, the vicor of silicon, in some strumas, the K-B lancet is even small, these values ​​simply do not matter.

Substation on MOS transistors

The modification on field-effect transistors, represented on the circuit, has many analogues. This includes a number of bipolar transistors. This can be considered as a similar butt with a sound-enhancing design assembled behind a circuit with a carbon emitter. The photo shows a diagram, vikonana by diagram, with a zagalny dzherel. R-C connections are assembled on the input and output lances so that the device operates in class “A” booster mode.

The alternating current from the cylinder to the signal is reinforced by the constant voltage of the capacitor C1. Obviously, the boost on field-effect transistors is due to the gate potential, which is lower for the same characteristic as the turn. In the diagram, the gate is connected to the igniter behind an additional resistor R1. This is a very great idea - expect 100-1000 kOhm resistors in designs. Such a large reference is chosen so that the signal is not shunted at the input.

This operation does not allow an electric current to pass through, as a result of which the potential of the gate (if there is a signal at the input) is the same as that of the ground. At first, the potential appears higher, lower near the ground, only because of the voltage drop on support R2. It is clear that the shutter has low potential, low on the cob. This itself is necessary for the normal functioning of the transistor. It is necessary to pay attention to those that C2 and R3 in this power supply circuit have the same significance as in the considered structure. And the input signal is disrupted by 180 degrees before the output signal.

ULF from a transformer at the output

You can make such a booster with your own hands for your home wiki. It follows the scheme that works in class “A”. The design is the same as in the above-mentioned objects - from a carbon emitter. One feature is that you need to change the transformer to make it work. There is not much of a similar boost to the sound on transistors.

The collector circuit of the transistor is connected to the primary winding, which develops an output signal that is transmitted through the secondary dynamics. On resistors R1 and R3 there is a voltage divider, which allows you to select the operating point of the transistor. This lanyard will ensure the supply of displacement voltage to the base. All other components have the same meanings as in the above-mentioned circuits.

Push-pull sound booster

It is impossible to say that this is a simple booster on transistors, the fragments of this robot are a little foldable, below those looked at earlier. For push-pull ULFs, the input signal is split into two phases, different in phase. And the skin of this type will be powered by its cascade, viconim on a transistor. After the skin tension has increased, the offensive signals are connected and sent to the speakers. Such complex transformations of the building will respond to the signal, the fragments of the dynamic and frequency power of the two, but on the circuit board, the transistors will be identical.

As a result, the sound brilliance at the output of the booster is significantly reduced. During the operation of the push-pull booster in class “A”, it is impossible to clearly produce a folding signal. The reason is that the movement of the struma flows through the shoulders steadily, asymmetrically, phases of co-operation occur. The sound becomes less intelligible, and when the signal is heated, it becomes even stronger, especially at low and super-low frequencies.

Transformerless ULF

Low-frequency booster on a transistor, vikonaniy with a transformer, regardless of the fact that the design can be of small dimensions, is still not thorough. Transformers are still important and bulky, so it’s better to worry about them. A highly effective circuit is based on complementary conductor elements with different types of conductivity. Most current ULFs follow such circuits and belong to class “B”.

Two hard transistors, which are used in the design, work behind the emitter repeater circuit (field collector). With this voltage, the input is transferred to the output without loss of power. If there is no signal at the input, the transistors are between switched on and still switched on. When a harmonic signal is applied to the input, the positive voltage of the first transistor is activated, and the other one is in the counter mode at that time.

Well, it’s too positive to go through this building. Otherwise, the other transistor is turned on negatively and the first one is completely short-circuited. In this case, more negative feelings are revealed in the obsessed ones. As a result of tightening, the signal appears at the output of the device. Such a transistor boost circuit is very effective and ensures stable operation, clearly related to sound.

ULF circuit on one transistor

Having taken into account all the features described above, you can assemble a booster with your own hands on a simple elemental basis. The transistor can be purchased from the KT315 or any foreign analogue - for example, the BC107. For reasons of convenience, it is necessary to use headphones based on 2000-3000 Ohms. A voltage must be applied to the base of the transistor through a resistor with a 1 MΩ support and a decoupling capacitor of 10 μF. Live circuits can be created with a voltage of 4.5-9 Volts, a voltage of 0.3-0.5 A.

If support R1 is not connected, then there will be no stream in the base and collector. However, when the voltage is connected, it reaches a level of 0.7 and allows a flow of about 4 µA. In this case, the power factor appears to be close to 250. From this, you can perform a simple expansion of the booster on the transistors and find out about the collector flow - it turns out to be as high as 1 mA. Having collected this booster circuit on a transistor, you can carry out its verification. Before exiting, connect your headphones.

If you press your finger, a characteristic noise will appear. If it is missing, then, most likely, the design is assembled incorrectly. Check all the connections and the values ​​of the elements. To start the demonstration, connect the audio output to the ULF input of the player or phone. Listen to the music and appreciate the richness of the sound.

- Susid steamed on the battery and knocked. Having played the music louder, just a little bit.
(From the folklore of audiophiles).

The epigraph is ironic, but the audiophile is not at all obligingly “sick all over” with the physiognomy of Josh Earnest at a briefing on food supply from the Russian Federation, which is “before” the fact that the neighbors are “happy”. I want to hear serious music at home, like in the hall. The strength of the equipment required for this is such that lovers of decibel power such as these simply do not fit there, where sensible people have reason, but in the remaining cases it is reasonable to go into prices for types of power supplies (UMZCH, podsil yuvach pressure of sound frequency). And at the same time, the need to get to the brown and spluttering spheres of activity - sound technology and burning electronics. The age of digital technologies is inextricably linked and can become a highly profitable and prestigious profession. The optimal first layer for all drains is on the right - make the reinforcement with your own hands: The UMZCH itself allows, with basic preparation on the basis of school physics on the same table, to go through the path from the simplest structures for the evening (which, prote, are bad for “sleeping”) to the most complex units, through which from the back a good rock band is playing. Meta of these publications – highlight the first stages of this journey for the beginnings and, perhaps, inform new evidence.

In simplest terms

So, now let’s try to create a sound booster that simply works. To get a thorough understanding of sound technology, you need to gradually master the theoretical material and not forget to gain a wealth of knowledge in the world of learning. Perhaps it will be easier to acquire wisdom if you move and move like you work in a warehouse. This article also cannot do without a theory - it is necessary to know the basics and what can be explained without formulas and graphs. In the meantime, it will be enough to use the multitester.

Note: If you have not soldered electronics before, ensure that the components do not overheat! Soldering iron - up to 40 W (more than 25 W), maximum permissible hour of soldering without interruption - 10 s. The soldering joints for heat dissipation are placed at a distance of 0.5-3 cm from the soldering area on the side of the body using medical tweezers. Acids and in. Active fluxes cannot be frozen! Solder - POS-61.

Livoruch in Fig.- The simplest UMZCH, “who just works.” This can be obtained on both germanium and silicon transistors.

At this point, it is important to master the basics of the UMZCH with direct connections between the cascades, which give the purest sound.

• Before the first increase in life, the speaker (speaker) must be turned off;
• Instead of R1, we solder the clamp from a constant resistor of 33 kΩ and a changeable (potentiometer) of 270 kΩ, then. first approx. four times less, and the other approx. double the larger nominal value compared to the output for the circuit;
• We supply life, turning the potentiometer motor, at the point marked with a cross, we set the indications of the VT1 manifold strim;
• We know the food supply, the time-sensitive resistors and the dimming of their fuss;
• As R1 we set the resistor to a value in the standard series, closest to the standard value;
• Replace R3 with a constant lanyard 470 Ohm + potentiometer 3.3 kOhm;
• Just like that, for pp. 3-5, incl. and the voltage is set to the same half of the live voltage.

Point a, the signal is received and the signal is received. the middle point of the force. For UMZCHs with unipolar food supplies, set it to half of its value, and for UMZCHs with bipolar food units, set it to zero according to the lead wire. This is called regulating the balance of power. In unipolar UMZCH with amniotic disconnection, switching on the connection for an hour of development is not obligatory, but rather starts working reflexively: unbalanced 2-polar booster from connecting the building to sleep their own hard and expensive output transistors, or else “new, good” and a very expensive heavy-duty speaker.

Note: components that require selection for a well-designed layout in the layout are indicated on the diagrams with either an asterisk (*) or an apostrophe (').

At the center of the same figure.- A simple UMZCH on transistors, which already develops a voltage of up to 4-6 W at an input of 4 ohms. I want to do it the same way as before, in the so-called. class AB1, not intended for Hi-Fi sound, but if you replace a pair of such boosters with class D (div. further) in cheap Chinese computer speakers, their sound will noticeably improve. Here we learn about another trick: hard output transistors need to be placed on radiators. Components that require additional cooling are outlined in dotted lines on the diagrams; True, far from it; Inodes - from the designated required area where heat dissipation is dissipated. Adjustment of this UMZCH - balancing after additional R2.

Right-handed in Fig.- Not yet a monster at 350 W (as per the indications on the cob of statistics), but still a completely solid beast: a simple booster on transistors with a voltage of 100 W. You can listen to music through nogo, but not Hi-Fi, robot class – AB2. However, for the sound of the square for a picnic or gathering in the open air, a school assembly or a small shopping hall, there are a whole number of annexes. An amateur rock band, looming behind such a UMZCH on an instrument, can successfully perform.

This UMZCH has two more tricks: first of all, in very tight boosters, the cascade of expansion of the tight output also needs to be cooled, then VT3 should be placed on a radiator of 100 square meters. div. For output VT4 and VT5 the required radiators are 400 sq. div. In other words, UMZCH from bipolar conditions cannot be balanced at all without vantage. Either one or the other output transistor is at the junction, and the connections are at the junction. Then, at the increased voltage of the stripping stream, with the balance being balanced, bring the output transistors out of tune. Therefore, for balancing (R6, guess what?), the power supply must be +/–24 V, and instead, a resistor of 100…200 Ohm must be switched on. Before speaking, the squiggles on the various resistors on the circuit are Roman numerals, which indicate the urgent need to dissipate heat.

Note: The lifeline for this UMZCH requires a power of 600 W. The filter capacitors that smooth are 6800 µF at 160 V. In parallel with the electrolytic capacitors IP, 0.01 µF ceramic capacitors are switched on to prevent self-excitation at ultrasonic frequencies, thereby burning the output circuits sistory.

On the floors

Next Small – another option is to power up a pressing UMZCH (30 W, and with a live voltage of 35 V – 60 W) on pressing field-effect transistors:

The sound of the new one is already drawn to the highest level of Hi-Fi (as, obviously, the UMZCH works on the corresponding acoustic systems, speakers). Tight flooring does not require great effort to get out of the way, so there is no pre-tension cascade. Even tighter field-effect transistors do not burn out the speakers due to frequent malfunctions - they themselves burn out faster. It’s still unacceptable, but it’s still cheaper, but it doesn’t change the way to the bass head of the Guchnomovtsya (RR). Balancing and maintenance of this UMZCH is not required. There is only one thing, like the design for cobs, only one: high-pressure field-effect transistors are much more expensive than bipolar ones for boosting with the same parameters. Vimogi before IP - similar to before. In case of emergency, 450 W is required. Radiators - 200 sq. div.

Note: There is no need to apply pressure to the UMZCH on the field-effect transistors of the pulse generators, for example. computers. When you try to “drive” them into the active mode, which is necessary for the UMZCH, the stench either simply burns, or the sound is weak, and the sound is “insignificant”. Those who worry about pressing high-voltage bipolar transistors, for example. from a small pile of old televisions.

Just up the mountain

If you have already harvested your first crumbs, then it will be completely natural to remember the eggplant UMZCH Hi-Fi class, without going too deep into the theoretical net. To expand the fleet of devices, you will need an oscilloscope, an audio frequency generator (AFG) and a millivoltmeter with the possibility of changing the stationary warehouse. The prototype for repetition is better to take E. Gumeli’s UMZCH, described in the report from “Radio” No. 1 for 1989. For your everyday life you need a few inexpensive, available components, but the brightness satisfies even the highest demands: power up to 60 W, darkness 20-20,000 Hz, frequency response unevenness 2 dB, coefficient of nonlinear responses (KHI) 0.01%, level of air noise -86 dB . However, it’s difficult to satisfy the supporter Gumeli; If you stick with it, you can join hands with someone else. Moreover, actions from the known circumstances will richly facilitate the successful UMZCH, div. lower. Bearing in mind that not everyone can get to the “Radio” archives, it would be best to repeat the main points.

Schemes of a simple high-acid UMZL

UMZCH Gumeli circuits and specifications before them are given in the illustration. Radiators of output transistors - 250 sq. div. for UMZCH for fig. 1 room 150 sq. div. for the option per fig. 3 (numbering is original). Transistors of the forward cascade (KT814/KT815) are installed on radiators bent from aluminum plates 75x35 mm with a thickness of 3 mm. Replacing KT814/KT815 with KT626/KT961 is not a good idea, the sound will not improve significantly, but it is seriously impossible to improve it.

This UMZCH is very critical in terms of electrical life, installation topology and wiring, so it is necessary to improve it for a structurally complete appearance and without the standard power supply. When you try to power it from a stabilized IP, the output transistors burn out immediately. Also in Fig. given the seating of the original wooden boards and inserts for better fitting. It can be added to them that, first of all, when the alarm “wake” is turned on for the first time, they fight it by changing the inductance L1. Otherwise, the pins of the parts installed on the board are to blame for not reaching 10 mm. Thirdly, it is unnecessary to change the topology of the installation, but, as required, the frame screen (earth loop, shown in color in the figure) is responsible for the main conductors, and the electrical paths pass behind it.

Note: rip in the tracks to which the bases of the power transistors are connected - technologically, for improvement, after which they are sealed with drops of solder.

The successful UMZCH will say goodbye a lot, and the risk of shutting down with the “wake-up” in the process of corruption will be reduced to zero, because:

• Minimize inter-block installation by placing the board on heat sinks of tight transistors.
• Be completely aware of the connectors in the middle, completing the entire installation without soldering. Then there will be no need for R12, R13 for the tight version or R10 R11 for the less tight version (they are dotted in the diagrams).
• Use acid-free honey for interior installation of audio cables with minimal maintenance.

There are no problems for the recovery of these minds from destruction, and the improvement of the UMZCH is reduced to a routine procedure, described in Fig.

Wire for sound

The audio wire is a mystery. The necessity of their consolidation is beyond doubt. Between copper and domestic acidity, a very fine mixture of oxide is created on the faces of crystallites in the metal. Metal oxides are conductors, since the strum of the dart is weak without permanent storage, its form is created. Behind the idea, the creation of myriads of crystallites is responsible for compensating one for the other, but a little (apparently due to quantum inconsistencies) is lost. It is enough to be marked by powerful listeners for the purest sound of today's UMZCH.

Distillers and traders shamelessly recommend replacing acid-free primary electrical copper - it is impossible to separate one at a time. However, this is a sphere of confinement, where the procedure cannot be clearly defined: the cable is twisted in pairs for computer connections. If you put the network with long segments “left”, it will either not start at all, or it will constantly glitch. Pulse dispersion, as you understand.

The author, since only a few people have already talked about audio wires, understands that, in principle, this is not an empty balakanin, moreover, since acid-free darts at that time had long been used in the technology of special purposes, which is responsible for the activity of the good know. Taking this and replacing the standard cord of your TDS-7 headphones with a self-contained one made from a “window” with a bunch of high-conductor wires. The sound, by ear, has been steadily reduced for cutting-edge analogue tracks, then. on the way from the studio microphone to the disc, which was not subject to digitization. Recordings on vinyl sounded especially bright, using DMM (Direct Metal Mastering) technology. After this, inter-unit installation of all home audio was converted to “Vitushny”. This improvement in sound began to be understood by people who were not familiar with music before and after.

How to earn interblock darts from torsion bets, div. video.

Video: do-it-yourself interblock darts with twisted pairs

It’s a pity that the little “Vitukha” little beast soon went up for sale - it was badly trimmed in the rosettes, so it was cuddled. However, before the readers are aware, only with acid-free honey will there be a strong “military” conduction of MGTF and MGTFE (screenings). The little bit is impossible, because... At the initial stage, the fluoroplastic insulation comes out quickly. MGTF is widely sold and is much cheaper than branded, guaranteed audio cables. There is only one problem: it can’t be easily colored, but it can be corrected with tags. And also acid-free winding darts, div.

Theoretical Interlude

As a matter of fact, having already mastered sound technology, we came across the concepts of Hi-Fi (High Fidelity), high fidelity to sound. There are different ranks of hi-fi, which are ranked as follows. main parameters:

1. Smoothies of created frequencies.
2. Dynamic range - the ratio in decibels (dB) of the maximum (peak) output pressure to the level of atmospheric noise.
3. Let's compare the noise levels in dB.
4. The coefficient of nonlinear stress (KNI) on the nominal (satisfactory) output force. LPC at peak tension is taken at 1% or 2% according to the vibrating technique.
5. Unevenness of the amplitude-frequency response (AFC) of a smoothie of operating frequencies. For speakers - okremo at low (LF, 20-300 Hz), middle (MF, 300-5000 Hz) and high (HF, 5000-20,000 Hz) sound frequencies.

Note: The ratio of absolute values ​​of any value I (dB) is calculated as P(dB) = 20lg(I1/I2). Yakshcho I1

You need to know all the subtleties and nuances of Hi-Fi when dealing with the design and operation of speakers, and since there is a need for a self-made Hi-Fi UMZCH for the home, then, first of all, we need to clearly understand the possibilities before it becomes necessary. ї for voicing this placement, dynamic range (speakers), level of external noise and KNI. Achieving UMZCH frequencies of 20-20,000 Hz with a rollover at the edges of 3 dB and an uneven frequency response in the midrange of 2 dB on the current elemental basis does not become a big problem.

Huchness

The loudness of the UMZCH is not an end in itself; it is necessary to ensure optimal loudness of the sound produced by the receiver. It can be calculated using the equal density curves, div. There is no natural noise in residential areas below 20 dB; 20 dB in the whole wilderness and in the late calm. A level of intensity of 20 dB is still possible at the threshold of sensitivity - at the threshold of diversity - the whispering of voices is still possible, otherwise the music is perceived as a fact of its obviousness. A successful musician can determine which instrument is playing, but not what he is playing.

40 dB is the normal noise of a well-insulated Russian apartment in a quiet area or a country house - this is the threshold of noise. Music from the threshold of diversity to the threshold of agility can be heard due to the presence of a deep correction of the frequency response, first of all, in the bass. For which in the current UMZCH introduce the MUTE function (mute, mutation, not mutation!), Which turns on the corresponding. original lancets in UMZL.

90 dB is equal to the volume of a symphony orchestra in a loud concert hall. 110 dB can be seen in an expanded orchestra in a hall with unique acoustics, of which there are no more than 10 in the world, but at the same time there is confusion: louder sounds are perceived as marked by the force of the will, or even loud noise. The noise zone in residential areas of 20-110 dB is the zone of extreme sensitivity, and 40-90 dB is the zone of extreme sensitivity, in which unprepared and under-informed ears fully perceive sensory sound. It is clear that no one has it.

Pushing

The adjustment of the intensity of the equipment for a given intensity in the listening area is not the main and most important thing for electroacoustics. For yourself, it is better to go with acoustic systems (AS): understand their tension using a simple method, and accept the nominal (accepted) pressure of the UMZ equal peak (musical) speaker. If the UMZCH does not clearly deliver its results to such speakers, the stink is mainly due to nonlinearity in the sound path. However, the operation of the UMZCH has happened in recent years: the level of high-volume noise may be higher than the sensitivity threshold, because It is important to determine the level of voltage output to the maximum tension signal. Since it is quite simple to understand, then for a room in an ordinary apartment or a cabin and speakers with normal sensitivity (sound output) you can take the following. UMZCH optimal tension values:

• Up to 8 sq. m – 15-20 W.
• 8-12 sq. m – 20-30 W.
• 12-26 sq. m - 30-50 W.
• 26-50 sq. m – 50-60 W.
• 50-70 sq. m – 60-100 W.
• 70-100 sq. m - 100-150 W.
• 100–120 sq. m - 150-200 W.
• Over 120 sq. m - is indicated by the layout of the acoustic worlds of the house.

Dynamics

The dynamic range of the UMZCH is determined by the equal intensity curves and threshold values ​​for different stages of shock:

1. Symphonic music and jazz with symphonic accompaniment – ​​90 dB (110 dB – 20 dB) ideal, 70 dB (90 dB – 20 dB) pleasant. A sound with a dynamics of 80-85 dB in a Moscow apartment does not qualify as an ideal daily expert.
2. Other serious musical genres - 75 dB “highly”, 80 dB “more dahu”.
3. Pop music of any kind and soundtracks to films - 66 dB per eye, because Even during recording, these recordings are compressed at levels up to 66 dB and up to 40 dB, so that you can hear what you want.

The dynamic range of the UMZCH, correctly selected for a given location, is considered equal to the level of atmospheric noise, taken by this sign + this sign. advanced signal/noise.

KNI

Non-linear solutions (NI) of the UMZCH - the difference in the spectrum of the output signal, which was not present in the input signal. Theoretically, it is best to “shut up” under the level of loud noises, but technically it is important to implement it. We really take it to your respects. masking effect: at thickness levels lower than approx. The 30 dB range of frequencies perceived by the human ear is sounded as the frequency of sounds is differentiated. Musicians can sense notes, but cannot evaluate the timbre of the sound. People without musical hearing can avoid the masking effect even at 45-40 dB volume. Therefore, the UMZCH with a efficiency of 0.1% (-60 dB compared to the level of gain of 110 dB) is rated as a Hi-Fi ordinary hearing speaker, and with a efficiency of 0.01% (-80 dB) it can be used with sound that does not interfere.

Lumpy

The remaining assertion, perhaps because it is unpleasant, even to the point of bitterness, among the adherents of tube circuit technology: having said that, the correct sound is produced only by tubes, and not just any, but also other types of octal ones. Calm down, gentlemen - the special tube sound is not a fiction. The reason is the fundamentally different voltage ranges of electric lamps and transistors. This is due to the fact that the flow of electrons in a lamp collapses in a vacuum and quantum effects appear in it. The transistor is a quantum device, where minor charge carriers (electrons and diks) collapse in the crystal, which would burn out without quantum effects. Therefore, the spectrum of tube products is short and pure: it can be clearly distinguished from harmonics to the 3rd – 4th, and the combination storage (the sum of the difference in frequencies of the input signal and their harmonics) is even small. Therefore, during the development of vacuum circuit technology, the LPC was called the harmonic coefficient (CH). In transistors, the spectrum of transistors (like vimiryans, vypadkova, div. lower) extends up to 15 or more high components, and combinations of frequencies, if you like.

For solid-state electronics, the designers of transistor UMZCHs took for them the initial “tube” KNI of 1-2%; sound from the lamp spectrum of such magnitude is perceived by ordinary listeners as pure. Among other things, the very concept of Hi-Fi did not yet exist. It appeared - it sounded dark and dull. During the development of transistor technology, understanding arose about what Hi-Fi was and what it needed.

At this time of crisis in the growth of transistor technology, it is important to successfully capture sub-frequencies and side frequencies at the output of a good UMZCH using special damping methods. And tube circuitry can be taken into account, which has become a mystery. Whatever the basis may be, why can’t electronics be there? Here the analogy with photography will be pre-river. No one can notice that today’s digital SLR produces a picture that is much clearer, clearer, deeper in the range of brightness and color, and a lower plywood screen with an accordion. I don’t want to turn Nikon “clicks photos” like “this fatty gut got drunk like a bastard and I’m sleeping with my paws outstretched,” but I want Smina-8M to take a photo in front of which people will flock to the prestigious exhibition.

Note: And calm down once again - not everything is so bad. Today, low-pressure lamp UMZCHs have lost one of the most important conditions and essential importance, for which the smell is technically necessary.

Additional stand

Many audio lovers, having quickly learned to solder, immediately “go to the lamp.” This is not always worthy of condemnation, however. The interest in the revolutions is now justified and red, and electronics have become tube-based. The first EOMs were tube-based, and the on-board electronic equipment of the first spacecraft was also tube-based: the transistors were also tube-based, but did not absorb ground-level radiation. Among other things, lamp microcircuits were created under the greatest secret! On microlamps with a cold cathode. There is only one clue about them in open fires in the rare book of Mitrofanov and Pickersgil “Day-drying-powerful lamps”.

Let’s finish the lyrics until it’s done. For those who like to tinker with the lamps in Fig. - Diagram of a bench lamp UMZCH, intended for experiments: SA1 is the operating mode of the output lamp, and SA2 is the live voltage. The circuit is well known in the Russian Federation, but minor modifications have been made to the output transformer: now it is possible to “run” the 6P7S in various modes, and to select for other lamps the coefficient of switching on the screen grid in ultralinear mode; for the important majority of output pentodes and exchange tetrodes, VIN is either 0.22-0.25 or 0.42-0.45. About the preparation of the output transformer div.

Guitarists and rockers

It's a shame if you can't get by without lamps. Apparently, the electric guitar became a full-fledged salting instrument after the signal from the pickup began to be passed through a special attachment - a fuser - which directly creates its spectrum. Without this, the sound of the string would be even sharper and shorter, because The electromagnetic pickup reacts only to the modes of mechanical vibrations at the surface of the instrument’s deck.

Suddenly an unpleasant situation appeared: the sound of an electric guitar with a fuser arouses greater strength and brightness at great depths. This is especially true for guitars with a humbucker type pickup, which gives an “angry” sound. And how can you start rehearsing at home if you are forced to rehearse? Don’t go to the performance hall without knowing exactly how to make the instrument sound there. And rock lovers simply want to hear their favorite speeches in full juice, and rockers are decent and non-confrontational people. Hire those who are celebrated by rock music itself, and not by the surroundings of the outrageous.

So, it turned out that the fatal sound appears at levels of noise suitable for residential applications, such as tube UMZCH. The reason is the specific interaction of the spectrum of the signal from the fuser with the pure and short spectrum of tube harmonics. Here again the pre-river analogy: a b/w photo can be much more colorful than a color one, because It makes it difficult to see the outline and the light.

Tim, who needs a tube booster not for experiments, but due to technical necessity, will take a long time to master thin tube electronics, which stinks of others. This type of UMZCH operates more efficiently without a transformer. More precisely, with a single-ended, comfortable output transformer, which operates without permanent magnetization. This approach will greatly simplify and speed up the preparation of the most complex and most reliable assembly of a lamp UMZCH.

"Transformerless" lamp output stage of the UMZCH and the front boosters to the next

Right-handed in Fig. a diagram of a transformerless output stage of a tube UMZCH is given, and a variant of the front booster for the new one is given. On-board - with a tone control using the classic Baxandal circuit, which ensures deep regulation, but also introduces a small phase interference signal, which can be difficult when operating an UMZCH on a 2-segment speaker. At the bottom, the tone control is simpler and does not interfere with the signal.

Let's turn around to the end. In a number of foreign devices, this circuit is widely known, but it is identical to it, except for the capacity of electrolytic capacitors, which appears in Radyansky’s “Radioamator Advice”, published in 1966. Tovstezna book with 1060 sides. There was no Internet or databases on disks.

In the same place, right-handed in the figure, a short but clear description of a few parts of this scheme. Improved from the same dzherel given to the next. Small right-handed Its screen mesh L2 is powered from the middle point of the anode rectifier (the anode winding of the power transformer is symmetrical), and the screen mesh L1 through the vantage. Instead of high-impedance speakers, turn on a suitable transformer from the primary speaker, like the one in front. diagram, the tightness of the bend is visible. 12 W, because The active support of the primary winding of the transformer is much less than 800 Ohms. SOI end cascade with transformer output - approx. 0.5%

How to build a transformer?

The main gates of the voltage signal low-frequency (sound) transformer - the magnetic field is dissipated, the power lines of which are closed, passing around the magnetoconductor (core), vortex jets in the magnetoconductor (Foucault jets) and, at least - the magician Nitostriction in the core. Through this phenomenon, a large number of transformers are “sleeping” and beeping. They fight against Foucault strums by changing the thickness of the plates to the magnetic circuit and additionally insulating them with varnish when folded. For output transformers, the optimal plate thickness is 0.15 mm, the maximum allowable is 0.25 mm. For the output transformer, the plates are thinner than the following: the coefficient of filling of the core (the central core of the magnetic core) falls into the steel, the crossbar of the magnetic core to extract the given tension will have to be increased, through which it will be created and spent in a new amount grow.

The core of an audio transformer that operates with permanent magnetization (for example, the anode strum of a single-ended output stage) is subject to a small (indicated by the expansion) non-magnetic gap. The presence of a non-magnetic gap, on one side, interferes with the signal of permanent magnetization; On the other hand, in a magnetic circuit of the primary type there is a larger dissipation field and causes a larger overcut. Therefore, the non-magnetic gap needs to be adjusted to the optimum and adjusted as accurately as possible.

For transformers that operate with magnetization, the optimal type of core is made of Shp (perforated) plates, pos. 1 in Fig. A non-magnetic gap is created during core penetration and is therefore stable; This value is indicated on the passport on the plate or measured with a set of probes. The field of dispersion is minimal, because The barrels, through which the magnetic flow is closed, are complete. From plates Шп the cores of transformers are often collected without magnetization, because The plates are made of high-acidity transformer steel. In this case, the core is collected crosswise (the plates are placed in the sieved sections, first in one, then in the other), and its girder is increased by 10% compared to the one in the other.

Transformers without magnetization are better than winding on USH cores (changed height with widened windows), pos. 2. Changes in the dissipation field are achieved with the help of changes in the magnetic field. Fragments of the plates are available for Shp, and cores of magnetized transformers are often collected from them. To assemble the core, proceed as follows: remove the package from the W-plates, put a mixture of non-conducting non-magnetic material equal to the size of the non-magnetic gap, cover the jumper with the yoke from the package and tie it together with a clip.

Note:"sound" signal magnetic conductors of the ShLM type for the output transformers of high-amplitude lamp boosters have little value, they have a large dissipation field.

At pos. 3 shows a diagram of the core dimensions for the transformer layout, at pos. 4 design of the winding frame, but in pos. 5 - form of details. As for the transformer for the “transformerless” output stage, it’s better to work on the ShLMm in crossfire, because The magnetization is negligible (the magnetization flow is the same as that of the screen mesh). The main task here is to make the windings of the yakomog more compact by changing the field of distribution; Their active reference still outputs less than 800 ohms. The more free place to lose from windows, especially your transformer. Therefore, the windings are wound turn to turn (since there is no winding machine, it is too dry) using a thin strand, the coefficient of laying the anode winding for mechanical winding of the transformer is 0.6. The winding wire is of the PETV or PEMM brands, they have a acid-free core. PETV-2 or PEMM-2 are not required, they have a larger external diameter and the field of dispersion will be larger. The primary winding should be wound first, because It is this field of dispersion itself that emits the most sound.

The cover of this transformer needs to be removed from the openings in the plates and clamps (div. Fig. on the right), because "For complete happiness" the folding of the magnetic circuit is carried out in a row. in order (obviously, the windings with ties and external insulation are already on the frame):

1. Prepare diluted acrylic varnish or, as usual, shellac;
2. The plates with bridges are lightly coated with varnish on one side and placed as quickly as possible, without suffocating too much, against the frame. Place the first plate with the varnished side in the middle, step on it with the unvarnished side to the first varnished side, etc.;
3. If the frame is damaged, apply staples and tighten tightly with bolts;
4. After 1-3 minutes, if the varnish from the gaps might stick out, add more plates until the window is filled;
5. Repeat paragraphs. 2-4 until the steel is tightly stuffed;
6. I need to tighten the core again and dry it on the battery. 3-5 dib.

Thanks to this technology, the core provides very good insulation of the plates and is filled with steel. No costs for magnetostriction are detected. Please note - for cores and their permalloy, the given method is not static, because In the face of strong mechanical influxes of magnetic power, the pearl will inevitably be swallowed up!

On microcircuits

UMZCH on integrated circuits (IMC) are most often used by those who have a high-quality sound up to average Hi-Fi, and what is more important is the cheapness, flexibility, ease of folding and the complete absence of any maintenance procedures, such as require special knowledge. Simply boosting on microcircuits is the best option for dummies. A classic of the genre here - UMZCH on IMC TDA2004, which stands on the series, God bless the memory, already 20 years old, evil in Fig. Potency – up to 12 W per channel, live voltage – 3-18 V, unipolar. Radiator area – 200 sq. div. for maximum tension. Gidnisty-the building of prazuvati on Duzha Nizkoomn, up to 1.6 ohms, Navantazhnia, the perpetrators of the bastard 12 V, and 7-8 W, at the 6-voltive living, to the motorcycle, on the motorcycle. However, the output of the TDA2004 in class B is not complementary (on transistors of the same conductivity), so the sound is definitely not Hi-Fi: KHI 1%, dynamics 45 dB.

More importantly, the TDA7261 produces sound no brighter, but louder, up to 25 W, because The upper limit of the voltage has been increased to 25 V. The lower limit, 4.5 V, still allows you to supply 6 V on board, then. The TDA7261 can be run practically in all on-board modes, except for 27 V aircraft. With additional attached components (connection, right-handed in the figure), the TDA7261 can be run in the muting mode and with the St-By (Stand By) function. what to translate UMZCH into mode of minimal energy consumption depending on the intensity of the input signal for a long time. The cost is pennies, so for stereo you will need a pair of TDA7261 with radiators of 250 square meters. div. for skin.

Note: If you want to get boosted by the St-By function, be careful - it’s not good to have wider speakers with them at 66 dB.

“Non-economical” according to the life of TDA7482, shown in the figure, which works in the same name. class D. Such UMZCH inodes are called digital boosters, which is incorrect. For proper digitization, the analog signal is taken from the analogue signal at the same time as the quantization frequency, no less than twice the frequency of the corresponding frequencies, the value of the skin signal is recorded with a factory code and saving There is for further vikoristannya. UMZCH class D – pulse. The analogue is directly converted into a sequence of high-frequency pulse-width modulated pulses (PWM), which is fed to the speaker through a low-pass filter (LPF).

The sound of class D from Hi-Fi does not have anything special: KHI of 2% and dynamics of 55 dB for UMZCH class D are respected by very good performance. And TDA7482 here, it must be said, the choice is not optimal: other companies that specialize in class D produce IMS UMZCH cheaper and require less wiring, for example, D-UMZCH series Paxx, right-handed in Fig.

From TDA, the following means 4-channel TDA7385, div. Fig., where you can get a good booster for speakers up to mid-range Hi-Fi, with a frequency cut of 2 mugs or for a system with a subwoofer. Filtering of LF and MF-HF in one case or another should be carried out at the input on a weak signal, which simplifies the design of the filters and allows for better separation of the dark substances. And if the acoustics are subwoofer, then 2 channels of the TDA7385 can be seen under the sub-ULF pickups (div. below), and there are 2 inputs for the midrange-HF.

UMZCH for subwoofer

A subwoofer, which can be translated as a “subwoofer” or, literally, a “booster”, produces frequencies up to 150-200 Hz, in which range the human ear has virtually no direct impact on sound. In a speaker with a subwoofer, install a “sub-bass” speaker in a hotel room with an acoustic design, without a subwoofer as such. The subwoofer is placed, in principle, more conveniently, and the stereo effect is ensured by the adjacent mid-HF channels and their small-sized speakers, until the acoustic design of any particularly serious ones can be avoided. It is common knowledge that it is better to listen to a stereo than a subwoofer system rather than to save money by investing in the bass path and making it easier to place acoustics in small spaces, which is why they are gaining popularity among their neighbors. What about basic hearing and not particularly powerful ones?

“Processing” of the midrange-high frequencies into the subwoofer, and from there the stereo is very weak, but if you sharply “cut off” the subbass, which, to say, is difficult and expensive, then the effect of jumping in the sound is even more unacceptable to the ear. Therefore, filtering of channels in subwoofer systems is carried out twice. At the input, electric filters show midrange-high frequencies with bass “tails”, so as not to over-inflate the midrange-high frequency path, but rather to ensure a smooth transition to the subbass. Bass with midrange “tails” are connected and fed to the UMZCH for the subwoofer. The midrange should be filtered so that the stereo is not lost, and the subwoofer is still acoustic: place the subwoofer, for example, in the partition between the resonator chambers of the subwoofer, so that the midrange is not released, dividingly.

Before the UMZCH, there are few specific benefits for the subwoofer, for which “dummies” require perhaps greater tension. This is completely wrong, since, say, the design of the acoustics in the room gives peak pressure W for one speaker, the subwoofer pressure requires 0.8 (2W) or 1.6W. Eg. If the S-30 speaker is suitable for the room, then a subwoofer is required 1.6x30 = 48 W.

It is much more important to ensure the presence of phase and transitional situations: if there is a smell, there will be a jump in the sound. As far as the efficiency is concerned, it is permissible up to 1%. The volume of bass production of such a level is not a little (amazing curves of equal density), and the “tails” of their spectrum in the most sensitive midrange region are not selected from the subwoofer.

To eliminate phase and transient problems, a booster for the subwoofer will be used. Brooks: turn on the outputs of 2 identical UMZCHs simultaneously through the speaker; input signals are sent to the antiphase. The presence of phase and transitional problems in the Brookian is due to the constant electrical symmetry of the output signal paths. The identity of the boosters that form the shoulders of the bridge is ensured by the installation of paired UMZCHs on the IMS, mounted on the same chip; This, perhaps, is a single failure, if the power supply on microcircuits is reduced to discrete.

Note: The tension of the pavement UMZCH does not correspond to the way the deeds respect, it is indicated by the tension of life.

Butt of the bridge UMZCH circuit for a subwoofer up to 20 sq. m (without input filters) on the TDA2030 IMC is given in Fig. evil. Additional filtering of the midrange is carried out using lancets R5C3 and R'5C'3. Radiator area TDA2030 – 400 sq. div. Bridge UMZCHs with an open output have an unacceptable feature: when the bridge is unbalanced in the stream, a stable warehouse appears, it is possible to keep the dynamics in tune, and the protection circuits for the subbass often fail, turning on the speaker, if not ba. It’s better to protect the “oak” bass head with non-polar batteries of electrolytic capacitors (shown in color, and the diagram of one battery is shown in the embed).

A little about acoustics

The acoustic design of a subwoofer is a special topic, but if the chair is given here, then further explanation is required. Case material – MDF 24 mm. The resonator tubes should be made of good plastic so as not to rattle, for example, polyethylene. The internal diameter of the pipes is 60 mm, the protrusion in the middle is 113 mm for the large chamber and 61 for the small one. For a particular head, the subwoofer will have to be re-adjusted for the deepest bass and, at the same time, for the least influx into the stereo effect. To tune the pipe, take a lot of time and, hanging and hanging, try to achieve the necessary sound. The protrusions of the pipes are called not to respond to the sound, then they are cut. The adjustment of the pipes is mutual, so there will be some tinkering.

Headphone booster

It is difficult to use a headphone booster with your own hands for two reasons. Persha is a rumor “on the go”, that is. Stay at home, unless the pressure on the audio output of the player or smartphone is enough to unwind the “gudziki” or “burdocks”. The other is for high-end home headphones. A Hi-Fi UMZCH for a typical living room requires a dynamic range of up to 70-75 dB, while the dynamic range of the shortest current stereo headphones exceeds 100 dB. A booster with such dynamics costs more than tens of cars, and its intensity will be over 200 W per channel, which is quite rich for a standard apartment: listening is much lower than the nominal intensity. sound, marvel more Therefore, there is a sense of creating a low-pressure, but with great dynamics, strong boost for headphones: prices for daily UMZCHs with such protection are clearly foolish.

The diagram of the simplest booster for headphones on transistors is given in pos. 1 pic. The sound is the same as for Chinese “sounds”, it operates in class B. The cost-effectiveness is also not affected - 13 mm lithium batteries last for 3-4 years at full capacity. At pos. 2 - TDA’s classic for headphone “on the go.” The sound, however, is entirely decent, up to mid-range Hi-Fi, depending on the digitization parameters of the track. The amateur upgrades of the TDA7050 binding are innumerable, but the transition of sound to the next level of class has not yet reached anyone: the “mikruha” itself does not allow it. TDA7057 (item 3) is simply functional, you can connect the intensity regulator to an original, non-double potentiometer.

UMZCH for headphones on TDA7350 (item 4) is already covered for the development of good individual acoustics. This IMS itself selects boosters for headphones from most everyday UMZCHs of the middle and high class. The UMZCH for headphones on KA2206B (item 5) is also respected by professionals: its maximum power of 2.3 W is suitable for handling such serious isodynamic “bugs” as TDS-7 and TDS-15.

The little one shows a 50 W power supply circuit with output MOSFET field-effect transistors.
The first boost stage is a differential boost on transistors VT1 VT2.
Another power cascade consists of transistors VT3 VT4. The end stage of the power supply consists of MOS transistors IRF530 and IRF9530. The output of the power supply through the L1 coil is connected to 8 ohms.
Lantsug, which consists of R15 and C5, is used to reduce noise. Capacitors C6 and C7 filter life. Support R6 is used for regulating the flow of fluid.

Note:
Vikoristovite bipolar dzherelo zhivlennya +/-35V
L1 consists of 12 turns of copper and insulated rod with a diameter of 1 mm.
C6 and C7 can be rated at 50V, other electrolytic capacitors at 16V.
A necessary heatsink for MOS transistors. Dimensions 20x10x10 cm made of aluminum.
Dzherelo - http://www.circuitstoday.com/mosfet-amplifier-circuits

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• Below are the principles of circuits and statistics from the topic “ULF on field-effect transistors” on the site from radioelectronics and radiohobbies site.

  What does “ULF on field-effect transistors” mean, the principles of circuits of self-contained devices are defined by the term “ULF on field-effect transistors”.

  The electronic principle is based on the circuit of a clumsy high-acid power booster for 20 Watts, it is wired entirely on transistors, and at the output there are field-effect transistors KP904. Scheme of a simple and powerful low-frequency booster with an output stage based on KP912 field-effect transistors. Maximum output power – 65 Watt. The principle is based on the circuit of a wide-skinned AF voltage booster (UMZCH), connected to a symmetrical circuit on KP904 field-effect transistors. In radio amateur practice, there is a wide expansion of the need for AF tension booster (UMZCH), following a symmetrical scheme. The complementary bipolar transistors of the input stage are connected behind the push-pull differential booster circuit, and the next one is connected behind the circuit. The diagram is aimed at the stepping baby. Its main technical characteristics... The high intensity of the audio frequency of class AB, described in this article, is based on the output stage of a pair of complementary field-effect MOSFET transistors. This feature allows you to improve the operating characteristics in line with the equivalent output stage on bipolar... ... Karel Barton designed his High-End UMZCH on field-effect transistors with a hexagonal structure (HEXFET from International Rectifier). The input stages are based on discrete bipolar transistors with symmetrical differential cascade circuitry... The "Power" UMZCH of Endre Piret is remarkably simple, and also meets the standards of high-acoustic sounds creation. Originally (without primary differential boosters) the input cascade is a double-ended complementary cascade. for a primary resistive booster cascade with an OE and a split capacitor, theoretically... Circuit diagram of the UMZCH, divided by Matt Tucker. The first differential cascade is based on bipolar transistors Q1Q5 for a standard circuit with a strum mirror Q7Q8 in a vantage, and the voltage amplification cascade is Q9Q13 with an OE and a strum generator Q6Q2. .. The electrical diagram of the power supply principle is placed on the baby (replacement elements are placed on the arms). This design is a modernization of the design. Principle diagram of UMZCH using MOSFET transistors (200W). All the main parts of the power supply are a transformer, radiators... A series of basic circuit diagrams of high-voltage UMZCHs on field-effect transistors, which are distinguished by their simplicity and technical characteristics. The use of field-effect transistors at high voltage allows you to significantly increase the brightness of the sound with a completely simplified circuit...
  

  Old and golden

  Old and golden

  The power supply circuitry has already undergone a spiral turn, and we are now expecting a “tube renaissance.” In accordance with the laws of dialectics, which we were so easily taught, the “transistor renaissance” may be coming. The very fact of this is inevitable, because the lamps, for all their beauty, are even intangible. Get home. Ale transistor boosters are wobbling their shortcomings...
  The reason for the “transistor” sound was explained back in the mid-70s - a deep gate connection. This gives rise to two problems. First - transient intermodulation reactions (TIM solutions) at the very booster, triggering the delayed signal in the gate loop. This can be fought with only one way - increasing the speed code and strengthening the output booster (without a return link), which threatens serious complications in the scheme. The result is important to predict: this way or that way.
  Another problem is that a deep turn-off ligament greatly reduces the output of the booster. And this, for most Guchnomovites, can lead to the culprit of these very intermodulation problems directly in the dynamic heads. The reason is that when the coil is moved into the gap of the magnetic system, its inductance significantly changes, and therefore the impedance of the head also changes. If the output support of the booster is low, it is necessary to make additional changes to the flow through the coil, which will give rise to unpleasant sounds that are mildly taken for the booster’s response. This can explain the paradoxical fact that, depending on the choice of speakers and boosters, one set “sounds,” and the other “does not sound.”

  secret of tube sound =
  high output support of the supporter
  + shallow lapel bell .
  However, similar results can be achieved with transistor boosters. All the circuits that are outlined below are one thing - non-traditional and neglected, neither “asymmetrical” nor “wrong” circuit design. But why is it so bad, as they say? For example, a phase inverter with a transformer is a true Hi-End! (Fig. 1) And the phase inverter with separate voltages (Fig. 2) is based on lamp circuitry.
  Fig.1

  
  Fig.2

  
  Fig.3

  These schemes are now undeservedly forgotten. And for free. On their basis, a vikory and natural elemental base, it is possible to create simple songs with high sounding vibrancy. You know, what I had a chance to pick up and hear sounded good - soft and “savory”. The depth of the gates in all schemes is small, there is little OOS, and the output support is significant. There is no irritable environmental impact of a permanent struma.

  However, the instituted schemes work with the class B That’s why they have their own “peremykalnye” solutions. To remove them, it is necessary to operate the output cascade in a “pure” class A. And such a scheme also appeared. The author of the scheme is J.L.Linsley Hood. The first mysteries in witchcraft dates back to the other half of the 70s.
  
  
  Fig.4

  The main shortcoming of the subsiluvach class A, which delimits the sphere of their stagnation - a great stream of calm. However, to eliminate the need for reconnection, another way is to use germanium transistors. Its worth - little difficulty in the mode B. (As long as I write a saga dedicated to Nimechina.) Another power supply is that it is not easy to know the transistors and the choice of connections. When repeating the same design, remember that the thermal stability of germanium transistors is low, so there is no need to save on radiators of the output stage.

  Fig.5

  This diagram shows a simple symbiosis of germanium transistors and polar ones. The sound is bright, regardless of its more modest characteristics, even harmonious. In order to refresh the ideas of a quarter of a century ago, I did not bother to collect the design on a mock-up, slightly modernizing it to suit the current ratings of parts. Transistor MP37 can be replaced with silicon KT315, but once everything is adjusted, you will still have to select the support of resistor R1. Based on 8 ohms, the voltage increases to approximately 3.5 W, the capacitance of capacitor C3 will increase to 1000 µF. And for work with 4 Ohm values, you will have to change the supply voltage to 15 volts, so as not to exceed the maximum voltage of the output stage transistors. Remnants of the fire OOS in a stationary stream are daily, the thermal stability is sufficient for work in the home.

  Two such schemes are particularly distinctive. The transistors of the output cascade of the alternating circuit are connected behind the circuit with a carbon emitter, which generates a small excitation voltage. No traditional voltage boost is required. However, for a steady stream of stench, it is switched on behind the circuit from the igniter collector, so for the life of the output cascade of vicors, a “floating” life source is not connected to the “ground”. Therefore, in order for the skin channel to exit the cascade, it is necessary to vikoristuvat around the body of life. When the pulse voltage is stagnant, this is not a problem. Dzherelo life of the front cascades can be hidden. Lantsugs OOS on a steady and changeable stream of separation, so that the stabilization stream connected with the lancet calmly guarantees high thermal stability at a small depth of OOS on the changeable stream. For MF/HF channels - a miracle scheme.
  
  Fig.6
  
  
  fig.7 Author: A.I. Shikhatov (compositions and comments) 1999-2000
  Published: collection "Designs and circuits for reading with a soldering iron" M. Solon-R, 2001, pp. 19-26.
  • Schemes 1,2,3,5 were published in the magazine "Radio".
  • Scheme 4 is included in the collection
    V.A. Vasilyev “Trans-Korean Radio Amateur Designs” M. Radio and Communications, 1982, pp. 14 ... 16
  • Schemes 6 and 7 are included in the assembly
    J. Bozdekh "Design of additional devices to tape recorders" (translated from Czech) M.Energovidav 1981, p.148,175
  • Report on the mechanism of intermodulation problems: What does the UMZCH mean in the least possible way?
  Zmist
  

  UMZCH on field-effect transistors

  UMZCH on field-effect transistors

  The use of field-effect transistors at high voltage allows you to significantly increase the brightness of the sound due to the simpler circuits. The transmitting characteristic of field-effect transistors is close to linear or quadratic, so in the spectrum of the output signal there are practically all-day paired harmonics, in addition, there is a slight decline in the amplitude of higher harmonics (like tube boosters ah). This allows you to insert a slight negative feedback in the boosters on field-effect transistors or to get rid of it. After conquering the space of home Hi-Fi, field-effect transistors began to attack car audio. The published circuits were primarily intended for home systems, otherwise there may be a risk of embedding ideas in them in a car.
  
  
  Fig.1
  This scheme is already considered classic. It has an output stage that operates in AB mode, oscillating on MOS transistors, and the front stages are on bipolar ones. The speaker will ensure that high readings are achieved, and to further reduce the brightness of the sound, the bipolar transistors should be switched off again in the circuits (see the picture below).
  
  
  Fig.2
  After all the reserves of increased sound brilliance have been exhausted, only one single-ended output stage of the “pure” class A. Strum is lost, which is absorbed by the front stages from the main voltage circuit both in this and in front This scheme is minimal.
  
  
  Fig.3
  The output stage with a transformer is a new analogue of lamp circuits. Here's a snack... The CR039 integrated generator designates the operating mode of the output cascade.
  
  
  Fig.4
  However, the wide-skinned output transformer is a foldable one from a prepared frame. Vitonchene solution - dzherelo struma in lanzyuzi drain - registered by the company