REVIEW OF LANZAR POWER AMPLIFIER
Frankly speaking, I was very surprised that the expression SOUND AMPLIFIER was gaining so much popularity. As far as my worldview allows me, only one object can act under the sound amplifier - a horn. It has really been amplifying sound for decades now. Moreover, the horn can amplify sound in both directions.
As can be seen from the photo, the horn has nothing in common with electronics, however, search queries for POWER AMPLIFIER are increasingly being replaced by SOUND AMPLIFIER, and the full name of this device, AUDITORY FREQUENCY POWER AMPLIFIER, is entered only 29 times a month versus 67,000 searches for SOUND AMPLIFIER.
I’m just curious what this is connected with... But that was a prologue, and now the fairy tale itself:
The schematic diagram of the LANZAR power amplifier is shown in Figure 1. This is an almost standard symmetrical circuit, which has made it possible to seriously reduce nonlinear distortions to a very low level.
This circuit has been known for quite a long time; back in the eighties, Bolotnikov and Ataev presented a similar circuit on a domestic element base in the book “Practical circuits for high-quality sound reproduction.” However, work with this circuitry did not begin with this amplifier.
It all started with the PPI 4240 car amplifier circuit, which was successfully repeated:
Schematic diagram of the PPI 4240 car amplifier
Next was the article “Opening Amplifier -2” from Iron Shikhman (the article has unfortunately been removed from the author’s website). It dealt with the circuitry of the Lanzar RK1200C car amplifier, where the same symmetrical circuitry was used as an amplifier.
It is clear that it is better to see once than to hear a hundred times, so delving into my hundred-year-old recorded discs, I found the original article and present it as a quote:
OPENING THE AMPLIFIER - 2
A.I. Shikhatov 2002
A new approach to the design of amplifiers involves the creation of a line of devices using similar circuit solutions, common components and style. This allows, on the one hand, to reduce design and manufacturing costs, and on the other hand, it expands the choice of equipment when creating an audio system.
The new line of Lanzar RACK amplifiers is designed in the spirit of rack-mounted studio equipment. The front panel, measuring 12.2 x 2.3 inches (310 x 60 mm), contains controls, and the rear panel contains all connectors. This arrangement not only improves the appearance of the system, but also simplifies the work - cables do not get in the way. On the front panel you can mount the included mounting strips and carrying handles, then the device takes on a studio look. The ring illumination of the sensitivity control only enhances the similarity.
The radiators are located on the side surface of the amplifier, which allows you to stack several devices in a rack without interfering with their cooling. This is an undoubted convenience when creating extensive audio systems. However, when installing in a closed rack, you need to worry about air circulation - install supply and exhaust fans, temperature sensors. In short, professional equipment requires a professional approach in everything.
The line includes six two-channel and two four-channel amplifiers, differing only in output power and cabinet length.
The block diagram of the crossover of the Lanzar RK series amplifiers is shown in Figure 1. A detailed diagram is not given, since there is nothing original in it, and it is not this unit that determines the main characteristics of the amplifier. The same or similar structure is used in most modern mid-priced amplifiers. The range of functions and characteristics are optimized taking into account many factors:
On the one hand, the crossover capabilities should allow the construction of standard audio system options (front plus subwoofer) without additional components. On the other hand, there is little point in introducing a full set of functions into a built-in crossover: This will significantly increase the cost, but in many cases it will remain unclaimed. It is more convenient to delegate complex tasks to external crossovers and equalizers, and to disable the built-in ones.
The design uses dual KIA4558S operational amplifiers. These are low-noise, low-distortion amplifiers designed with "audio" applications in mind. As a result, they are widely used in preamp stages and crossovers.
The first stage is a linear amplifier with variable gain. It matches the output voltage of the signal source with the sensitivity of the power amplifier, since the gain of all other stages is equal to unity.
The next stage is the bass boost control. In amplifiers of this series, it allows you to increase the signal level at a frequency of 50 Hz by 18 dB. In products from other companies, the rise is usually less (6-12 dB), and the tuning frequency can be in the region of 35-60 Hz. By the way, such a regulator requires a good power reserve of the amplifier: an increase in gain by 3 dB corresponds to doubling the power, by 6 dB - quadrupling, and so on.
This is reminiscent of the legend about the inventor of chess, who asked the Raja for one grain for the first square of the board, and for each subsequent one - twice as many grains as for the previous one. The frivolous Raja could not fulfill his promise: there were no such quantity of grains on the entire Earth... We are in a more advantageous position: an increase in the level by 18 dB will increase the signal power “only” 64 times. In our case, 300 W are available, but not every amplifier can boast such a reserve.
The signal can then be fed directly to a power amplifier, or the required frequency band can be selected using filters. The crossover part consists of two independent filters. The low-pass filter is tunable in the range of 40-120 Hz and is designed to work exclusively with a subwoofer. The tuning range of the high-pass filter is noticeably wider: from 150 Hz to 1.5 kHz. In this form, it can be used to work with a broadband front or for the MF-HF band in a system with channel amplification. The tuning limits, by the way, were chosen for a reason: in the range from 120 to 150 Hz there is a “hole” in which the acoustic resonance of the cabin can be hidden. It is also noteworthy that the bass booster is not turned off in any of the modes. Using this cascade simultaneously with a high-pass filter allows you to adjust the frequency response in the interior resonance region no worse than using an equalizer.
The last cascade has a secret. Its task is to invert the signal in one of the channels. This will allow you to use the amplifier in a bridge connection without additional devices.
Structurally, the crossover is made on a separate printed circuit board, which is connected to the amplifier board using a connector. This solution allows the entire line of amplifiers to use only two crossover options: two-channel and four-channel. The latter, by the way, is simply a “double” version of the two-channel one and its sections are completely independent. The main difference is the changed layout of the printed circuit board.
Amplifier
The Lanzar power amplifier is made according to a typical scheme for modern designs, shown in Figure 2. With minor variations, it can be found in most amplifiers of the middle and lower price category. The only difference is in the types of parts used, the number of output transistors and supply voltage. The diagram of the right channel of the amplifier is shown. The left channel circuit is exactly the same, only the part numbers start with a one instead of a two.
A filter R242-R243-C241 is installed at the amplifier input, eliminating radio frequency interference from the power supply. Capacitor C240 does not allow the DC component of the signal to enter the power amplifier input. These circuits do not affect the frequency response of the amplifier in the audio frequency range.
To avoid clicks when turning on and off, the amplifier input is connected to a common wire with a transistor switch (this unit is discussed below, together with the power supply). Resistor R11A eliminates the possibility of self-excitation of the amplifier when the input is closed.
The amplifier circuit is completely symmetrical from input to output. A double differential stage (Q201-Q204) at the input and a stage on transistors Q205, Q206 provide voltage amplification, the remaining stages provide current amplification. The cascade on transistor Q207 stabilizes the quiescent current of the amplifier. To eliminate its "unbalance" at high frequencies, it is bypassed with a mylar capacitor C253.
The driver stage on transistors Q208, Q209, as befits a preliminary stage, operates in class A. A “floating” load is connected to its output - resistor R263, from which the signal is removed to excite the transistors of the output stage.
The output stage uses two pairs of transistors, which made it possible to extract 300 W of rated power and up to 600 W of peak power. Resistors in the base and emitter circuits eliminate the consequences of technological variation in the characteristics of transistors. In addition, resistors in the emitter circuit serve as current sensors for the overload protection system. It is made on transistor Q230 and controls the current of each of the four transistors in the output stage. When the current through an individual transistor increases to 6 A or the current of the entire output stage to 20 A, the transistor opens, issuing a command to the blocking circuit of the supply voltage converter.
The gain is set by the negative feedback circuit R280-R258-C250 and is equal to 16. Correction capacitors C251, C252, C280 ensure the stability of the amplifier covered by OOS. The circuit R249, C249 connected at the output compensates for the increase in load impedance at ultrasonic frequencies and also prevents self-excitation. In the audio circuits of the amplifier, only two electrolytic non-polar capacitors are used: C240 at the input and C250 in the OOS circuit. Due to their large capacity, it is extremely difficult to replace them with other types of capacitors.
Power supply The high-power power supply is made of field-effect transistors. A special feature of the power supply is the separate output stages of the converter for powering the power amplifiers of the left and right channels. This structure is typical for high-power amplifiers and makes it possible to reduce transient interference between channels. For each converter there is a separate LC filter in the power supply circuit (Figure 3). Diodes D501, D501A protect the amplifier from erroneous switching on in the wrong polarity.
Each converter uses three pairs of field-effect transistors and a transformer wound on a ferrite ring. The output voltage of the converters is rectified by diode assemblies D511, D512, D514, D515 and smoothed by filter capacitors with a capacity of 3300 μF. The output voltage of the converter is not stabilized, so the power of the amplifier depends on the voltage of the on-board network. From the negative voltage of the right and positive voltage of the left channel, parametric stabilizers generate voltages of +15 and -15 volts to power the crossover and differential stages of power amplifiers.
The master oscillator uses the KIA494 (TL494) microcircuit. Transistors Q503, Q504 increase the output of the microcircuit and speed up the closing of the key transistors of the output stage. The supply voltage is supplied to the master oscillator constantly, the switching is controlled directly from the Remote circuit of the signal source. This solution simplifies the design, but when turned off, the amplifier consumes insignificant quiescent current (several milliamps).
The protection device is made on a KIA358S chip containing two comparators. The supply voltage is supplied to it directly from the Remote circuit of the signal source. Resistors R518-R519-R520 and a temperature sensor form a bridge, the signal from which is fed to one of the comparators. A signal from the overload sensor is supplied to another comparator through a driver on transistor Q501.
When the amplifier overheats, a high voltage level appears at pin 2 of the microcircuit, and the same level appears at pin 8 when the amplifier is overloaded. In any emergency case, signals from the output of the comparators through the OR diode circuit (D505, D506, R603) block the operation of the master oscillator at pin 16. Operation is restored after eliminating the causes of the overload or cooling the amplifier below the temperature sensor response threshold.
The overload indicator is designed in an original way: the LED is connected between the +15 V voltage source and the on-board network voltage. During normal operation, voltage is applied to the LED in reverse polarity and it does not light. When the converter is blocked, the +15 V voltage disappears, the overload indicator LED turns on between the on-board voltage source and the common wire in the forward direction and begins to glow.
Transistors Q504, Q93, Q94 are used to block the input of the power amplifier during transient processes when turning on and off. When the amplifier is turned on, capacitor C514 is slowly charged, transistor Q504 is in the open state at this time. The signal from the collector of this transistor opens the keys Q94,Q95. After charging the capacitor, transistor Q504 closes, and the -15 V voltage from the output of the power supply reliably blocks the keys. When the amplifier is turned off, transistor Q504 instantly opens through diode D509, the capacitor quickly discharges and the process is repeated in the reverse order.
Design
The amplifier is mounted on two printed circuit boards. On one of them there is an amplifier and a voltage converter, on the other there are crossover elements and turn-on and overload indicators (not shown in the diagrams). The boards are made of high-quality fiberglass with a protective coating for the tracks and are mounted in a housing made of an aluminum U-shaped profile. Powerful transistors of the amplifier and power supply are pressed with pads to the side shelves of the case. Profiled radiators are attached to the outside of the sides. The front and rear panels of the amplifier are made of anodized aluminum profile. The entire structure is secured with self-tapping screws with hexagon heads. That's all, actually - the rest can be seen in the photographs.
As you can see from the article, the original LANZAR amplifier itself is not bad at all, but I wanted it to be better...
I searched the forums, of course, Vegalab, but didn’t find much support - only one person responded. Perhaps it’s for the better - there aren’t a ton of co-authors. Well, in general, this particular appeal can be considered Lanzar’s birthday - at the time of writing the comment, the board was already etched and soldered almost completely.
So Lanzar is already ten years old...
After several months of experiments, the first version of this amplifier, called "LANZAR", was born, although of course it would be fairer to call it "PIPIAY" - it all started with him. However, the word LANZAR sounds much more pleasant to the ear.
If someone SUDDENLY considers the name an attempt to play on a brand name, then I dare to assure him that there was nothing like that in mind and the amplifier could have received absolutely any name. However, it became LANAZR in honor of the LANZAR company, since this particular automotive equipment is included in that small list of those who are personally respected by the team that worked on fine-tuning this amplifier.
A wide range of supply voltages makes it possible to build an amplifier with a power from 50 to 350 W, and at powers up to 300 W for UMZCH coffee. nonlinear distortion does not exceed 0.08% throughout the entire audio range, which allows the amplifier to be classified as Hi-Fi.
The figure shows the appearance of the amplifier.
The amplifier circuit is completely symmetrical from input to output. A double differential stage (VT1-VT4) at the input and a stage on transistors VT5, VT6 provide voltage amplification, the remaining stages provide current amplification. The cascade on transistor VT7 stabilizes the quiescent current of the amplifier. To eliminate its “asymmetry” at high frequencies, it is bypassed with capacitor C12.
The driver stage on transistors VT8, VT9, as befits a preliminary stage, operates in class A. A “floating” load is connected to its output - resistor R21, from which the signal is removed to excite the transistors of the output stage. The output stage uses two pairs of transistors, which made it possible to extract up to 300 W of rated power from it. Resistors in the base and emitter circuits eliminate the consequences of technological variation in the characteristics of transistors, which made it possible to abandon the selection of transistors by parameters.
We remind you that when using transistors from the same batch, the spread in parameters between transistors does not exceed 2% - this is the manufacturer’s data. In reality, it is extremely rare that parameters go beyond the three percent zone. The amplifier uses only “one-party” terminal transistors, which, together with balance resistors, made it possible to maximally align the operating modes of the transistors with each other. However, if the amplifier is being made for a loved one, then it will not be useless to assemble the test stand given at the end of THIS ARTICLE.
Regarding the circuitry, it only remains to add that such a circuitry solution provides one more advantage - complete symmetry eliminates transient processes in the final stage (!), i.e. at the moment of switching on, there are no surges at the output of the amplifier, which are characteristic of most discrete amplifiers.
Figure 1 - schematic diagram of the LANZAR amplifier. INCREASE .
Figure 2 - appearance of the LANZAR V1 amplifier.
Figure 3 - appearance of the LANZAR MINI amplifier
Schematic diagram of a powerful stage power amplifier 200 W 300 W 400 W UMZCH on high quality transistors Hi-Fi UMZCH
Power amplifier specifications:
390
As can be seen from the characteristics, the Lanzar amplifier is very versatile and can be successfully used in any power amplifiers that require good UMZCH characteristics and high output power.
You can, of course, praise this amplifier for quite a long time, but it is somehow not modest to engage in self-praise. Therefore, we decided to look at the reviews of those who heard how it works. I didn’t have to search for long - this amplifier has been discussed on the Soldering Iron forum for a long time, so take a look for yourself: There were, of course, negative ones, but the first was from an incorrectly assembled amplifier, the second from an unfinished version with a domestic configuration... The audio frequency power amplifier UM LANZAR based on powerful bipolar transistors will allow you to assemble a very high-quality audio frequency amplifier in a short period of time. Power supply ±70 V - 3.3 kOhm...3.9 kOhm Of course, ALL resistors are 1 W, zener diodes at 15V are preferably 1.3 W Regarding heating VT5, V6 - in this case you can increase the radiators on them or increase their emitter resistors from 10 to 20 Ohms. About LANZAR amplifier power filter capacitors: |
Since this amplifier is quite popular and questions about making it yourself quite often come up, the following articles were written:
Transistor amplifiers. Basics of circuit design
Transistor amplifiers. Building a balanced amplifier
Lanzar tuning and circuit design changes
Setting up the LANZAR power amplifier
Increasing the reliability of power amplifiers using the example of the LANZAR amplifier
The penultimate article quite intensively uses the results of parameter measurements using the MICROCAP-8 simulator. How to use this program is described in detail in a trilogy of articles:
AMPovichok. CHILDREN'S
AMPovichok. YOUTHFUL
AMPovichok. ADULT
BUY TRANSISTORS FOR LANZAR AMPLIFIER |
|
And finally, I would like to give the impressions of one of the fans of this circuit, who assembled this amplifier on his own:
The amplifier sounds very good, the high damping factor represents a completely different level of low frequency reproduction, and the high slew rate does an excellent job of reproducing even the smallest sounds in the high and midrange ranges.
You can talk a lot about the delights of the sound, but the main advantage of this amplifier is that it does not add any color to the sound - it is neutral in this regard, and only repeats and amplifies the signal from the sound source.
Many who heard the sound of this amplifier (assembled according to this circuit) gave the highest rating to its sound as a home amplifier for high-quality speakers, and its endurance in *close to military action* conditions gives the chance to use it professionally for scoring various outdoor events , as well as in the halls.
For a simple comparison, I will give an example that will be most relevant among radio amateurs, as well as among those already *experienced with good sound*
in the soundtrack of Gregorian-Moment of Peace, the choir of monks sounds so realistic that the sound seems to pass right through, and the female vocals sound as if the singer is standing right in front of the listener.
When using time-tested speakers such as 35ac012 and others like them, the speakers get a new lease of life and sound just as clearly even at maximum volume.
For example, for fans of loud music, when listening to the music track Korn ft. Skrillex - Get Up
The speakers were able to play all the difficult moments with confidence and without noticeable distortion.
As a contrast to this amplifier, we took an amplifier based on the TDA7294, which, already at a power of less than 70 W per 1 channel, was able to overload the 35ac012 so that it was clearly audible how the woofer coil hit the core, which was fraught with damage to the speaker and, as a result, losses.
The same cannot be said about the *LANZAR* amplifier - even with about 150W of power supplied to these speakers, the speakers continued to work perfectly, and the woofer was so well controlled that there were simply no extraneous sounds.
In the musical composition Evanescence - What You Want
The scene is so elaborate that you can even hear the drumsticks hitting each other. And in the composition Evanescence - Lithium Official Music Video
The skipping part is replaced by an electric guitar, so that the hair on your head just begins to move, because there is simply no *longness* to the sound, and the quick transitions are perceived as if a painful form of 1 is flashing in front of you, in one moment and YOU are immersed in a new world. Not forgetting about the vocals, which throughout the entire composition bring generalization to these transitions, giving harmony.
In the composition Nightwish - Nemo
The drums sound like gunshots, clearly and without boom, and the rumble of thunder at the beginning of the composition simply makes you look around.
In the composition Armin van Buuren ft. Sharon den Adel - In and Out of Love
We are again immersed in the world of sounds that penetrate us through and through, giving us a feeling of presence (and this is without any equalizers or additional stereo expansions)
In the song Johnny Cash Hurt
We are again immersed in the world of harmonious sound, and the vocals and guitar sound so clearly that even the increasing tempo of the performance is perceived as if we are sitting behind the wheel of a powerful car and pressing the gas pedal to the floor, while not letting go but pressing harder and harder.
With a good source of sound signal and good acoustics, the amplifier *doesn't bother you* at all, even at the highest volume.
Once a friend was visiting me and he wanted to listen to what this amplifier was capable of, putting on a track in AAC format Eagles - Hotel California, he turned it up to full volume, while instruments began to fall from the table, his chest felt like well-placed punches of a boxer , the glass tinkled in the wall, and we were quite comfortable listening to music, while the room was 14.5 m2 with a ceiling of 2.4 m.
We installed ed_solo-age_of_dub, the glass in two doors cracked, the sound was felt by the whole body, but the head did not hurt.
The board on the basis of which video was made in LAY-5 format.
If you assemble two LANZAR amplifiers, can they be bridged?
You can, of course, but first, a little poetry:
For a typical amplifier, the output power depends on the supply voltage and load resistance. Since we know the load resistance and we already have power supplies, it remains to be seen how many pairs of output transistors to use.
Theoretically, the total output power of alternating voltage is the sum of the power supplied by the output stage, which consists of two transistors - one n-p-n, the second p-n-p, therefore each transistor is loaded with half the total power. For the sweet couple 2SA1943 and 2SC5200, the thermal power is 150 W, therefore, based on the above conclusion, 300 W can be removed from one pair of outputs.
But practice shows that in this mode the crystal simply does not have time to transfer heat to the radiator and thermal breakdown is guaranteed, because the transistors must be insulated, and the insulating spacers, no matter how thin they are, still increase the thermal resistance, and the surface of the radiator is unlikely to who polishes to micron precision...
So for normal operation, for normal reliability, quite a lot of people have adopted slightly different formulas for calculating the required number of output transistors - the output power of the amplifier should not exceed the thermal power of one transistor, and not the total power of the pair. In other words, if each transistor of the output stage can dissipate 150 W, then the output power of the amplifier should not exceed 150 W, if there are two pairs of output transistors, then the output power should not exceed 300 W, if three - 450, if four - 600.
Well, now the question is - if a typical amplifier can output 300W and we connect two such amplifiers in a bridge, then what will happen?
That's right, the output power will increase approximately twofold, but the thermal power dissipated by the transistors will increase by 4 times...
So it turns out that to build a bridge circuit you will no longer need 2 pairs of outputs, but 4 on each half of the bridge amplifier.
And then we ask ourselves the question - is it necessary to drive 8 pairs of expensive transistors to get 600 W, if you can get by with four pairs simply by increasing the supply voltage?
Well, of course, it’s the owner’s business....
Well, several options of PRINTED BOARDS for this amplifier will not be superfluous. There are also original versions, and some taken from the Internet, so it’s better to double-check the board - it will give you mental training and fewer problems when adjusting the assembled version. Some options have been corrected, so there may not be any errors, or maybe something has slipped through the cracks...
One more question remains unanswered - assembly of the LANZAR amplifier on a domestic element base.
Of course, I understand that crab sticks are made not from crabs, but from fish. So is Lanzar. The fact is that in all attempts to assemble on domestic transistors, the most popular ones are used - KT815, KT814, KT816, KT817, KT818, KT819. These transistors have a lower gain and a unity gain frequency, so you won’t hear Lanzarov’s sound. But there is always an alternative. At one time, Bolotnikov and Ataev proposed something similar in circuit design, which also sounded pretty good:
You can see more details about how much power a power supply is needed for a power amplifier in the video below. The STONECOLD amplifier is taken as an example, but this measurement makes it clear that the power of the network transformer may be less than the power of the amplifier by about 30%.
At the end of the article, I would like to note that this amplifier requires a BIPOLARY power supply, since the output voltage is formed from the positive side of the power supply and the negative one. The diagram of such a power supply is shown below:
You can draw conclusions about the overall power of the transformer by watching the video above, but I’ll give a short explanation about the other details.
The secondary winding must be wound with a wire whose cross-section is designed for the overall power of the transformer plus an adjustment for the shape of the core.
For example, we have two channels of 150 W each, therefore the overall power of the transformer must be at least 2/3 of the power of the amplifier, i.e. with an amplifier power of 300 W, the power of the transformer must be at least 200 W. With a power supply of ±40 V into a 4 Ohm load, the amplifier develops about 160 W per channel, therefore the current flowing through the wire is 200 W / 40 V = 5 A.
If the transformer has an W-shaped core, then the voltage in the wire should not exceed 2.5 A per square mm of cross-section - this way there is less heating of the wire, and the voltage drop is less. If the core is toroidal, then the voltage can be increased to 3...3.5 A per 1 square mm of wire cross-section.
Based on the above, for our example, the secondary must be wound with two wires and the beginning of one winding is connected to the ends of the second winding (the connection point is marked in red). The diameter of the wire is D = 2 x √S/π.
At a voltage of 2.5 A we get a diameter of 1.6 mm, at a voltage of 3.5 A we get a diameter of 1.3 mm.
The diode bridge VD1-VD4 not only must calmly withstand the resulting current of 5 A, it must withstand the current that occurs at the moment of switching on, when it is necessary to charge the power filter capacitors C3 and C4, and the higher the voltage, the greater the capacitance, the higher the value of this starting current. Therefore, the diodes must be at least 15 Amperes for our example, and in the case of increasing the supply voltage and using amplifiers with two pairs of transistors in the final stage, 30-40 Ampere diodes or a soft start system are needed.
The capacity of capacitors C3 and C4, based on Soviet circuit design, is 1000 μF for every 50 W of amplifier power. For our example, the total output power is 300 W, which is 6 times 50 W, therefore the capacitance of the power filter capacitors should be 6000 uF per arm. But 6000 is not a typical value, so we round up to the typical value and get 6800 µF.
Frankly speaking, such capacitors do not come across often, so we put 3 capacitors of 2200 μF in each arm and get 6600 μF, which is quite acceptable. The issue can be solved somewhat simpler - use one 10,000 µF capacitor
COLLECTING LANZAR
The repetition of the same questions on every page of discussion about this amplifier prompted me to write this short sketch. Everything written below is my idea of what you need to know. beginner to the radio amateur who decided to make this amplifier, and does not pretend to be the absolute truth.
Let's say you are looking for a good transistor amplifier circuit. Circuits such as “UM Zueva”, “VP”, “Natalie”, and others seem complicated to you, or you have little experience in assembling them, but you want good sound. Then you have found what you were looking for! Lanzar is an amplifier built according to a classical symmetrical circuit, with an output stage operating in class AB, and has a pretty good sound, in the absence of complex settings and scarce components.
Amplifier circuit:
I found it necessary to make some minor changes to the original circuit: the gain was slightly increased - up to 28 times (R14 was changed), the values of the input filter R1, R2 were changed, as well as according to the advice May Be I'm a Leo resistor ratings of the base divider of the thermal stabilization transistor (R15, R15’) for smoother adjustment of the quiescent current. The changes are not critical. The numbering of elements has been preserved.
Amplifier power
Amplifier power supply- the most expensive link in it, so you should start with it. Below are a few words about IP.
Based on the load resistance and the desired output power, the desired supply voltage is selected (Table 1). This table is taken from the source site (interlavka.narod.ru), however, I personally urgently I would not recommend operating this amplifier at powers exceeding 200-220 watts.
REMEMBER! This is not a computer, no super-cooling is needed, the design should not work at the limit of its capabilities, then you will get a reliable amplifier that will work for many years and delight you with sound. We decided to make a high-quality device, and not a bouquet of New Year’s fireworks, so let all sorts of “squeezers” go through the forest.
For supply voltages below ±45 V/8 Ohm and ±35 V/4 Ohm, the second pair of output transistors (VT12, VT13) can be omitted! At such supply voltages, we get an output power of about 100 W, which is more than enough for a home. I note that if you install 2 pairs at such voltages, the output power will increase by a very insignificant amount, on the order of 3-5 W. But if “the toad is not strangling,” then in order to increase reliability, you can install 2 pairs.
Transformer power can be calculated using the program "PowerSup". Calculation based on the fact that the approximate efficiency of the amplifier is 50-55%, which means the transformer power is equal to: Ptrans=(Pout*Nchannels*100%)/efficiency applicable only if you want to listen to a sine wave for a long time. In a real music signal, unlike a sine wave, the ratio of peak to average values is much smaller, so there is no point in spending money on extra transformer power that will never be used anyway.
In the calculation, I recommend choosing the “heaviest” peak factor (8 dB), so that your power supply does not bend if you suddenly decide to listen to music with such a p-f. By the way, I also recommend calculating the output power and supply voltage using this program. For Lanzar dU you can choose about 4-7 V.
More details about the program "PowerSup" and calculation methods are written in website author (AudioKiller).
All this is especially true if you decide to buy a new transformer. If you already have it in your bins, and suddenly it turns out to have more power than the calculated one, then you can safely use it, a reserve is a good thing, but there is no need for fanaticism. If you decide to make a transformer yourself, then on this page of Sergei Komarov there is a normal calculation method .
The circuit itself the simplest bipolar power supply looks like that:
The circuit itself and the details for its construction are well described by Mikhail (D-Evil) in FAKe according to TDA7294.
I will not repeat myself, I will only note the amendment about the power of the transformer, described above, and about diode bridge: since Lanzar’s supply voltage can be higher than that of the TDA729x, the bridge must “hold” a correspondingly higher reverse voltage, no less than:
Urev_min = 1.2*(1.4*2*Uhalf-winding_of the transformer) ,
where 1.2 is the safety factor (20%)
And with large transformer powers and capacitances in the filter, in order to protect the transformer and bridge from colossal inrush currents, the so-called. “soft start” or “soft start” scheme.
Amplifier parts
A list of parts for one channel is attached in the archive in
Some denominations require special explanation:
C1– coupling capacitor must be of good quality. There are different opinions on the types of capacitors used as isolation capacitors, so those experienced will be able to choose the best option for themselves. For the rest, I recommend using polypropylene film capacitors from well-known brands such as Rifa PHE426, etc., but in the absence of such, widely available lavsan K73-17 are quite suitable.
The lower limit frequency, which will be amplified, also depends on the capacitance of this capacitor.
In the printed circuit board from interlavka.narod.ru, as C1 there is a seat for a non-polar capacitor, composed of two electrolytes, connected with “minuses” to each other and “pluses” in the circuit and shunted by a 1 µF film capacitor:
Personally, I would throw out the electrolytes and leave one film capacitor of the above types, with a capacity of 1.5-3.3 μF - this capacity is enough to operate the amplifier at “wideband”. In the case of working with a subwoofer, a larger capacity is required. Here it would be possible to add electrolytes with capacities of 22-50 μF x 25 V. However, the printed circuit board imposes its own limitations, and a 2.2-3.3 μF film capacitor is unlikely to fit there. Therefore, we set 2x22 uF 25 V + 1 uF.
R3, R6– ballast. Although initially these resistors were chosen to be 2.7 kOhm, I would recalculate them to the required supply voltage of the amplifier using the formula:
R=(Ushoulder – 15V)/Ist (kOhm) ,
where Ist – stabilization current, mA (about 8-10 mA)
L1 – 10 turns of 0.8 mm wire on a 12 mm mandrel, everything is smeared with superglue, and after drying a resistor is placed inside R31.
Electrolytic capacitors C8, C11, C16, C17 The voltage must be calculated to be no lower than the supply voltage with a margin of 15-20%, for example, at ±35 V, 50 V capacitors are suitable, and at ±50 V, you need to select 63 Volts. The voltages of other electrolytic capacitors are indicated in the diagram.
Film capacitors (non-polar) are usually not made rated for less than 63 V, so this should not be a problem.
Trimmer resistor R15– multi-turn, type 3296.
Under emitter resistorsR26, R27, R29 and R30– the board provides seats for ceramic wires S.Q.P. 5 W resistors. The range of acceptable values is 0.22-0.33 Ohm. Although SQP is far from the best option, it is affordable.
You can also use domestic resistors C5-16. I haven't tried it, but they might even be better than SQP.
Other resistors– C1-4 (carbon) or C2-23 (MLT) (metal film). All except those indicated separately - at 0.25 W.
Some possible replacements:
Another illustration of the beta measurement process:
Transistors 2SC5200/2SA1943 are the most expensive components in this circuit and are often counterfeited. Similar to the real 2SC5200/2SA1943 from Toshiba, they have two break marks on top and look like this:
It is advisable to take identical output transistors from the same batch (in Figure 512 is the batch number, i.e., say both 2SC5200 with number 512), then the quiescent current when installing two pairs will be distributed more evenly across each pair.
Printed circuit board
The printed circuit board was taken from interlavka.narod.ru. The corrections on my part were mainly of a cosmetic nature; some errors in the signed values were also corrected, such as mixed up resistors for the thermal stabilization transistor and other little things. The board is drawn from the parts side. There is no need to mirror to make LUTs!
First launch and setup
Once again, we carefully check everything, if everything looks normal, there are no errors, “snot”, short circuits to the radiator, etc., then you can proceed to the first start.
IMPORTANT! The first start-up and setup of any amplifier must be carried out with input shorted to ground, power supply current limited and no load . Then the chance of burning something is greatly reduced. The simplest solution that I use is incandescent lamp 60-150 W connected in series with the primary winding of the transformer:
We run the amplifier through the lamp, measure the DC voltage at the output: normal values are no more than ±(50-70) mV. “Walking” constant within ±10 mV is considered normal. We control the presence of voltages of 15 V on both zener diodes. If everything is normal, nothing exploded or burned, then we proceed to the setup.
When starting a working amplifier with a quiescent current = 0, the lamp should flash briefly (due to the current when charging the capacitors in the power supply), and then go out. If the lamp is bright, it means something is faulty, turn it off and look for the error.
As already mentioned, the amplifier is easy to set up: you only need set the quiescent current (TC) output transistors.
It should be exhibited on "warm up" amplifier, i.e. Before installation, let it play for a while, 15-20 minutes. During installation of the TP, the input must be short-circuited to ground and the output suspended in the air.
The quiescent current can be found by measuring the voltage drop across a pair of emitter resistors, e.g. R26 And R27(set the multimeter to the limit of 200 mV, probes to the emitters VT10 And VT11):
Accordingly, Ipok = Uv/(R26+R26) .
Further SMOOTHLY, without jerking we turn the trimmer and look at the multimeter readings. Required to install 70-100 mA. For the resistor values indicated in the figure, this is equivalent to the multimeter reading (30-44) mV.
The light bulb may begin to glow a little. Let's check the DC voltage level at the output again, if everything is normal, you can connect the speakers and listen.
Photo of the assembled amplifier
Other useful information and possible troubleshooting options
Amplifier self-excitation: Indirectly determined by the heating of the resistor in the Zobel circuit - R28. Reliably determined using an oscilloscope. To eliminate this, try increasing the ratings of the correction capacitors C9 And C10.
High level of DC component at the output: select differential cascade transistors ( VT1 and VT3), (VT2 and VT4) by "Betta". If it doesn’t help, or there is no way to choose more precisely, then you can try changing the value of one of the resistors R4 And R5. But this solution is not the best; it is still better to choose transistors.
Option to slightly increase sensitivity: You can increase the sensitivity of the amplifier (gain) by increasing the resistor value R14. Coef. gain can be calculated by the formula:
Ku = 1+R14/R11, (once)
But don’t get too carried away, because with increasing R14, the depth of the environmental feedback decreases and the unevenness of the frequency response and SOI increases. It is better to measure the output voltage level of the source at full volume (amplitude) and calculate what Ku is needed to operate the amplifier with the full output voltage swing, taking it with a margin of 3 dB (before clipping).
For specifics, let the maximum to which it is tolerable to raise Ku is 40-50. If you need more, then make a preamplifier.
If you have any questions, write to the appropriate topic to the forum . Happy building!
Photo sent by Alexander (Allroy), Novorossiysk
Historical reference
The Oda 102 Stereo stereo radio complex has been produced by the Murom RIP plant since 1986. The complex provided reception of mono and stereo broadcasts in the VHF range, recording of mono and stereo programs, with subsequent playback. The complex consisted of 5 functionally complete units: VHF tuner “Oda-102S”, cassette recorder-set-top box “Oda-302S”, power amplifier “Oda UM-102S”, pre-amplifier “Oda UP-102S” and 2 acoustic systems "15AS-213".
Fragment excluded. Our magazine exists on donations from readers. The full version of this article is available only
VT5, VT6 are equipped with small radiators, which are an aluminum plate 10x20 mm.
--
Thank you for your attention!
Igor Kotov, editor-in-chief of Datagor magazine
Thank you for your attention!
Andrey Zelenin,
Kyrgyzstan, Bishkek
So, it all started last year when I wanted to build a powerful amplifier for a car subwoofer. The project began in the summer of 2012 and lasted 3 long and painstaking months, but everything was delayed due to lack of finances and time.
With the amplifier circuit, I also spent a long time thinking about what to choose? Among the sea of high-quality amplifier circuits, the choice fell on an amplifier based on the Lanzar circuit.
Why Lanzar? In fact, lanzar is the simplest of all similar circuits; it can produce quite high power (up to 350 watts).
The circuit has a relatively simple design and a small number of components. Only after assembling and configuring the amplifier, it was decided to purchase a subwoofer head. I made the box for the subwoofer by hand, and it turned out very well.
A little more than a year has passed since then and it was decided to manufacture a HI-Fi amplifier complex. It was decided to assemble as many as 11 high-quality amplifiers on a common board!
I didn’t spend a long time fiddling with schematics and boards; I just had to etch the board and start assembling.
We have a problem with etching reagents, so the solution was made from 11 bottles of hydrogen peroxide, 8 sachets of citric acid and 5 teaspoons of table salt. All components must be mixed thoroughly until the salt and citric acid are completely dissolved.
Hydrogen peroxide - was purchased at a pharmacy. They are sold in 100mg bottles, 3% hydrogen peroxide.
Citric acid - purchased at your local grocery store.
Table salt is ordinary table salt, I think everyone has it in their home.
This solution poisons the board very quickly; it took 35 minutes to do everything, even though I placed the solution in the sun.
Amplifier Lanzar. The repetition of the same questions on every page of discussion about this amplifier prompted me to write this short sketch. Everything written below is my idea of what a novice radio amateur needs to know who decides to make this amplifier, and does not claim to be the absolute truth.
Let's say you are looking for a good transistor amplifier circuit. Circuits such as “UM Zueva”, “VP”, “Natalie”, and others seem complicated to you, or you have little experience in assembling them, but you want good sound. Then you have found what you were looking for! Amplifier Lanzar It is an amplifier built according to a classic symmetrical circuit, with an output stage operating in class AB, and has a pretty good sound, without complicated settings and scarce components.
I found it necessary to make some minor changes to the original circuit: the gain was slightly increased - up to 28 times (R14 was changed), the values of the input filter R1, R2 were changed, and also, on the advice of MayBe I'm a Leo, the resistor values of the base divider of the thermal stabilization transistor (R15 , R15') for smoother adjustment of the quiescent current. The changes are not critical. The numbering of elements has been preserved.
Amplifier power supply- the most expensive link in it, so you should start with it. Below are a few words about IP.
Based on the load resistance and the desired output power, the desired supply voltage is selected (Table 1). This table was taken from the original source site, however, I personally would strongly not recommend operating this amplifier at powers of more than 200-220 Watts.
REMEMBER! This is not a computer, no super-cooling is needed, the design should not work at the limit of its capabilities, then you will get a reliable amplifier that will work for many years and delight you with sound. We decided to make a high-quality device, and not a bouquet of New Year’s fireworks, so let all sorts of “squeezers” go through the forest.
For supply voltages below ±45 V/8 Ohm and ±35 V/4 Ohm, the second pair of output transistors (VT12, VT13) can be omitted! At such supply voltages, the Lanzar amplifier receives an output power of about 100 W, which is more than enough for a home. I note that if you install 2 pairs at such voltages, the output power will increase by a very insignificant amount, on the order of 3-5 W. But if “the toad is not strangling,” then in order to increase reliability, you can install 2 pairs.
Transformer power can be calculated using the PowerSup program. A calculation based on the fact that the approximate efficiency of the amplifier is 50-55%, which means that the power of the transformer is equal to: Ptrans = (Pout * N channels * 100%) / efficiency is applicable only if you want to listen to a sine wave for a long time. In a real music signal, unlike a sine wave, the ratio of peak to average values is much smaller, so there is no point in spending money on extra transformer power that will never be used anyway.
In the calculation, I recommend choosing the “heaviest” peak factor (8 dB), so that your power supply does not bend if you suddenly decide to listen to music with such a p-f. By the way, I also recommend calculating the output power and supply voltage using this program. For the Lanzar dU amplifier, you can choose about 4-7 V.
More details about the “PowerSup” program and the calculation method are written on the author’s website (AudioKiller).
All this is especially true if you decide to buy a new transformer. If you already have it in your bins, and suddenly it turns out to have more power than the calculated one, then you can safely use it, a reserve is a good thing, but there is no need for fanaticism. If you decide to make a transformer yourself, then on this page of Sergei Komarov there is a normal calculation method.
The circuit itself of the simplest bipolar power supply looks like this:
The circuit itself and the details for its construction are well described by Mikhail (D-Evil) in TDA7294.
I will not repeat myself, I will only note an amendment about the power of the transformer, described above, and about the diode bridge: since the Lanzar amplifier can have a supply voltage higher than the TDA729x, the bridge must “hold” a correspondingly higher reverse voltage, no less:
Urev_min = 1.2*(1.4*2*Uhalf-winding_of the transformer) ,
where 1.2 is the safety factor (20%)
And with large transformer powers and capacitances in the filter, in order to protect the transformer and bridge from colossal inrush currents, the so-called. “soft start” or “soft start” scheme.
A list of parts for one channel is attached in the archive in the file
Some denominations require special explanation:
C1– separation capacitor, Lanzar amplifier must be of good quality. There are different opinions on the types of capacitors used as isolation capacitors, so those experienced will be able to choose the best option for themselves. For the rest, I recommend using polypropylene film capacitors from well-known brands such as Rifa PHE426, etc., but in the absence of such, widely available lavsan K73-17 are quite suitable.
The lower limit frequency, which will be amplified, also depends on the capacitance of this capacitor.
In the printed circuit board, as C1, there is a seat for a non-polar capacitor, composed of two electrolytes, connected with “minuses” to each other and “pluses” in the circuit and shunted by a 1 μF film capacitor:
Personally, I would throw out the electrolytes and leave one film capacitor of the above types, with a capacity of 1.5-3.3 μF - this capacity is enough to operate the amplifier at “wideband”. In the case of working with a subwoofer, a larger capacity is required. Here it would be possible to add electrolytes with capacities of 22-50 μF x 25 V. However, the printed circuit board imposes its own limitations, and a 2.2-3.3 μF film capacitor is unlikely to fit there. Therefore, we set 2x22 uF 25 V + 1 uF.
R3, R6– ballast. Although initially these resistors were chosen to be 2.7 kOhm, I would recalculate them to the required supply voltage of the amplifier using the formula:
R=(Ushoulder – 15V)/Ist (kOhm) ,
where Ist – stabilization current, mA (about 8-10 mA)
L1– 10 turns of 0.8 mm wire on a 12 mm mandrel, everything is lubricated with superglue, and after drying, resistor R31 is placed inside.
Electrolytic capacitors C8, C11, C16, C17 must be designed for a voltage no lower than the supply voltage with a margin of 15-20%, for example, at ±35 V capacitors of 50 V are suitable, and at ±50 V you need to choose 63 Volts . The voltages of other electrolytic capacitors are indicated in the diagram.
Film capacitors (non-polar) are usually not made rated for less than 63 V, so this should not be a problem.
Trimmer resistor R15 – multi-turn, type 3296.
For emitter resistors R26, R27, R29 and R30 – the board provides seats for wire-wound ceramic SQP resistors with a power of 5 W. The range of acceptable values is 0.22-0.33 Ohm. Although SQP is far from the best option, it is affordable.
The Lanzar amplifier also requires the installation of domestic resistors C5-16. I haven't tried it, but they might even be better than SQP.
The remaining resistors are C1-4 (carbon) or C2-23 (MLT) (metal film). All except those indicated separately - at 0.25 W.
Another illustration of the beta measurement process:
Transistors 2SC5200/2SA1943 are the most expensive components in this circuit and are often counterfeited. Similar to the real 2SC5200/2SA1943 from Toshiba, they have two break marks on top and look like this:
It is advisable to take identical output transistors from the same batch (in Figure 512 is the batch number, i.e., say both 2SC5200 with number 512), then the quiescent current when installing two pairs will be distributed more evenly across each pair.
The corrections on my part were mainly of a cosmetic nature; some errors in the signed values were also corrected, such as mixed up resistors for the thermal stabilization transistor and other little things. The board is drawn from the parts side. There is no need to mirror to make LUTs!
Once again, we carefully check everything, if everything looks normal, there are no errors, “snot”, short circuits to the radiator, etc., then you can proceed to the first start.
IMPORTANT! The first startup and setup of any amplifier must be carried out with input shorted to ground, power supply current limited and no load . Then the chance of burning something is greatly reduced. The simplest solution that I use is incandescent lamp 60-150 W connected in series with the primary winding of the transformer:
We run the amplifier through the lamp, measure the DC voltage at the output: normal values are no more than ±(50-70) mV. “Walking” constant within ±10 mV is considered normal. We control the presence of voltages of 15 V on both zener diodes. If everything is normal, nothing exploded or burned, then we proceed to the setup.
When starting a working amplifier with a quiescent current = 0, the lamp should flash briefly (due to the current when charging the capacitors in the power supply), and then go out. If the lamp is bright, it means something is faulty, turn it off and look for the error.
As already mentioned, the amplifier is easy to configure: you only need to set the quiescent current (TC) of the output transistors.
It should be set on a “warm up” amplifier, i.e. Before installation, let it play for a while, 15-20 minutes. During installation of the TP, the input must be short-circuited to ground and the output suspended in the air.
The quiescent current can be found by measuring the voltage drop across a pair of emitter resistors, for example on R26 and R27 (set the multimeter to the limit of 200 mV, probes on the emitters VT10 and VT11):
Respectively, Ipok = Uv/(R26+R26) .
Next, SMOOTHLY, without jerking, turn the trimmer and look at the multimeter readings. It is required to set 70-100 mA. For the resistor values indicated in the figure, this is equivalent to the multimeter reading (30-44) mV.
The light bulb may begin to glow a little. Let's check the DC voltage level at the output again, if everything is normal, you can connect the speakers and listen.
Self-excitation of the amplifier: Indirectly determined by the heating of the resistor in the Zobel circuit - R28. Reliably determined using an oscilloscope. To eliminate this, try increasing the ratings of correction capacitors C9 and C10.
High level of DC component at the output: select transistors of the differential stages (VT1 and VT3), (VT2 and VT4) according to “Betta”. If it doesn’t help, or there is no way to choose more precisely, then you can try changing the value of one of the resistors R4 and R5. But this solution is not the best; it is still better to choose transistors.
Option to slightly increase sensitivity: You can increase the sensitivity of the amplifier (gain) by increasing the value of resistor R14. Coef. gain can be calculated by the formula:
Ku = 1+R14/R11, (once)
But you shouldn’t get too carried away, since with an increase in R14, the depth of the feedback decreases and the unevenness of the frequency response and SOI increases. It is better to measure the output voltage level of the source at full volume (amplitude) and calculate what Ku is needed to operate the amplifier with the full output voltage swing, taking it with a margin of 3 dB (before clipping).
For specifics, let the maximum to which it is tolerable to raise Ku is 40-50. If you need more, then make a preamplifier.
Download: Printed circuit board
Download all files in one archive:
