Lanzar is a high-quality transistor class AB Hi-Fi amplifier with high output power. During the course of the article, I will explain in as much detail as possible the process of assembling and setting up the specified amplifier in the language of a novice radio amateur. But before we start talking about it, let's look at the plate with the amplifier's parameters.
| PARAMETER | power amplifier circuit diagram of the Lanzar power amplifier operation description recommendations for assembly and adjustment | ||
| PER LOAD |
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| 2 Ohm |
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| Maximum supply voltage, ± V | |||
| Maximum output power, W at distortion up to 1% and supply voltage: | |||
| ±30 V | |||
| ±35 V | |||
| ±40 V | |||
| ±45 V | |||
| ±55 V | |||
| ±65 V | 240 | One of the important parameters is nonlinear distortion, at 2/3 of the maximum power it is 0.04%, and at the maximum power 0.08-0.1% - this almost allows us to classify this amplifier as a Hi-Fi of a fairly high level. Lanzar is a symmetrical amplifier and is built entirely on complementary switches, the circuit diagram has been known since the 70s. The maximum output power of an amplifier with 2 pairs of output switches into a 4 Ohm load with a bipolar power supply of 60 Volts is 390 Watt under a 1 kHz sinusoidal signal. Some people strongly disagree with this statement, I personally have never tried to remove the maximum power, the maximum was 360 watts with a stable 4-ohm load during tests, but I think it is quite possible to remove the indicated power, of course, the distortions will be quite large and the normal operation of the amplifier when trying to remove the specified power for a long time. Amplifier power is carried out from an unstabilized bipolar source, the amplifier efficiency is 65-70% at best, all remaining power is dissipated in the form of unnecessary heat on the output transistors. The assembly of the amplifier begins with the manufacture of a printed circuit board, after etching and drilling holes for the components, it is imperative to tin all the tracks on the board; in addition, it would not hurt to strengthen the power supply tracks with an extra layer of tin. We do the assembly by installing small components - resistors, then low-power transistors and capacitors. At the end we install the largest components - final stage transistors and electrolytes. Pay attention to the variable resistor that regulates the quiescent current of the output stage; in the diagram it is designated X1 - 3.3 kOhm. In some versions the resistor is 1 kOhm. I highly recommend using this resistor as a multi-turn resistor for the most precise adjustment of the quiescent current. In this case, the resistor must initially, before installation, be screwed to the larger side (to maximum resistance). Let's look at the list of necessary components to assemble the specified circuit.
The costs for the components are not small, it will cost around $40 taking into account all the details, of course without a power supply. If you want to use a mains transformer to power such a monster, most likely you will have to fork out another $20-30, since taking into account the efficiency of the amplifier, you will need a mains transformer with a power of 400-500 watts. The amplifier consists from several main components, in theory the same circuit diagram was known to our grandfathers. The sound initially enters the double differential stage, in fact, this is where the initial sound is formed. All, all subsequent stages are voltage and current amplifiers. The output stage is a simple current amplifier; in our case, two pairs of powerful 2SC5200/2SA1943 switches with a dissipation power of 150 watts are used. The pre-output stage is a voltage amplifier, and the previous stage, built on VT5/VT6 switches, is a current amplifier. In general, cascades that are current amplifiers should overheat quite strongly and need cooling. Transistor BD139 (a complete analogue of KT315G) is a regulating transistor for the quiescent current of the output stage. Resistor R18 (47Ohm) plays an important role in the circuit. The sound signal to excite the transistors of the output stage is removed from this resistor. The amplifier circuit itself is push-pull, which means that the output (and indeed all) transistors open at a certain half-wave of the sine wave, amplifying only the lower or upper half-cycle. Power supply for diff cascades in any self-respecting amplifier it is supplied stabilized, or stabilized directly on the amplifier board, the same in the case of lanzar. In the circuit you can see two Zener diodes with a stabilization voltage of 15 Volts. Take the specified zener diodes with a power of 1-1.5 watts, you can use any (including domestic ones) Before assembly, carefully check all components to ensure they are in good working order, even if they are completely new. Particular attention should be paid to transistors and powerful resistors that are in the power supply circuit of the transistors. The value of the emitter resistors 5 watt 0.33 Ohm can deviate from 0.22 to 0.47 Ohm, I don’t recommend it anymore, you will only increase the heating on the resistor. After the end of the amplifier Before starting, I advise you to check the installation, the location of components, and errors on the installation side several times. If you are sure that you have not gone too far with the values, all the switches and capacitors are soldered in correctly, you can move on. VT5/VT6 - we install it on a heat sink; due to their operating mode, quite strong overheating is observed. At the same time, in the case of using a common heat sink for the indicated switches, do not forget to insulate them with mica gaskets and plastic washers, the same in the case of the remaining transistors (except for low-power switches of differential stages. After installation, take a multimeter and set it to diode testing mode. We place one of the screws on the heat sink, with the second we touch the terminals of all the keys in turn, checking the short circuit of the keys with the heat sink; if everything is correct, then there should be no short circuits. Resistors R3/R4 play a very important role. They are designed to limit the power supply to differential stages and are selected based on the supply voltage.
These resistors should be taken with a power of 1-2 watts. Next, carefully connect the power buses and start the amplifier, initially connecting the input wire to the middle power point (to ground). After starting, wait a minute, then turn off the amplifier. We check the components for heat generation. Initially I advise run the amplifier through a bipolar network power supply of 30 Volts (in the shoulder) and through a series-connected incandescent lamp of 40-100 watts. When connected to a 220 Volt network, the lamp should light up briefly and go out; if it lights up all the time, then turn it off and check everything after the transformer (rectifier unit, capacitors, amplifier) Well, if everything is fine, then we disconnect the amplifier input from the ground and start the amplifier again, not forgetting to connect the dynamic head. If everything is ok, then there should be a slight click from the acoustics. Then, without turning off the amplifier, touch the input wire with your finger, the head should roar, if everything is so, then congratulations! the amplifier is working! But that doesn't mean that everything is ready and you can enjoy it, everything is just beginning! Next, we connect the audio signal and turn on the amplifier at about 40% of the maximum volume; those who don’t mind acoustics can turn it up to maximum. It is advisable to first connect modern music, not classics, and enjoy for about 15 minutes. As soon as the heat sink is warm, we begin the second stage - adjusting the quiescent current of the output stage. For this, the diagram provides a 3.3 kOhm variable, which was discussed earlier. Setting the quiescent current from a photograph After setting the quiescent current, we proceed to the next part - measuring the output power of our amplifier, but this step is not necessary. Capture power output you need a 1 kHz sinusoidal signal into a 4 ohm load. As a constant load, you need to use a resistor immersed in water or a resistor assembly with a resistance of 4 Ohms. The resistor should have a power of 10-30 watts, preferably with as little inductance as possible. At this point, the assembly and configuration process has come to its logical end. The printed circuit board is Our lanzar is in the attachment, you can download it and safely assemble it, it has been tested several times (to be more precise, over 10 times). All that remains is to decide where you will use the amplifier, at home or in the car. In the case of the latter, most likely you will need a powerful voltage converter, which we have repeatedly discussed on the pages of the site. | |
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.
Good evening, gentlemen radio amateurs! It all started with the fact that in his home UMZCH had long wanted to abandon cheap TDA-sheks and move to a higher level - a decent transistor audio amplifier. I read many pages of a wide variety of forums, looked through various photo galleries, reviewed reviews... and decided to try to assemble a new one for myself; the choice fell on a very well-known Lanzar amplifier with good characteristics. Then a month was spent studying all possible types of circuits for this amplifier and choosing the optimal one and the one that was suitable in terms of characteristics.Schematic diagram of ULF Lanzar
It seemed to me relatively easy to repeat and customize, although it is the one that gets the most attention on all the forums! Well, I went to the radio market, bought parts, the price cost me 110 UAH - a lot for a student, I’ll tell you, but the end result was worth it, more on that later... I set about making a printed circuit board, with etching took an hour and a half. I poisoned with ferric chloride, I’m not used to it yet since I mainly use copper sulfate. After preparing the board of the future, Lanzara took up soldering, first of all, jumpers were soldered in, then resistors, capacitors, transistors...
Having soldered the board, we move on to the main thing - setting the no-load current of the UMZCH. Here everything was simple for me - I set the trimmer to the average value, soldered it, checked the board for snot and turned it on. Even without fuses (not like light bulbs). Lanzar started up immediately, drove it for 15 minutes until the VC warmed up, but the trimmer did not pull, measured the voltage drop on the five-watt resistors - it did not change, no noise or other noticeable distortions were detected with an oscilloscope, which showed the high repeatability of this circuit!
Now about the impressions of the sound: earlier when listening tda7294
for at least an hour and the subsequent exception it felt as if a tightly stretched helmet had been removed from my head, then I realized that this was due to a lack of midrange frequencies tda7294
.
Now it’s time to load the lanzar with a pair of low-power speakers, since my power supply is +-22V test, then small 25-watt speakers were just right for it.
Photo of the finished UMZCH
As you can see from the pictures, the power supply capacitors are not very fat, only 470 uF, but in terms of voltage they have a large margin, since it is planned in the future to power Lanzar from +- 65V! These speakers were connected to the amplifier during the setup process.
If you are interested in this article, then you have already read a lot of positive reviews on websites and various forums. Quite a few radio amateurs have already repeated this scheme, and, as we understand, they did not regret their choice. It is clear that transistor amplifiers are superior in sound quality to amplifiers implemented on microcircuits. LANZAR has an amazingly low coefficient of nonlinear distortion, and with a fairly wide range of supply voltage it allows you to develop 50...300 Watts of power at a load. And even at three hundred watts, these distortions do not exceed 0.08% over the entire audio range. Briefly about the amplifier parameters:
Gain coefficient – 24 dB;
Coef. nelin. distortion at 60% power - % 0.04%;
The slew rate of the output signal is at least 50 V/µS;
Input impedance – 22 kOhm;
Signal-to-noise ratio, no less than 90 dB;
Supply voltage, ± 30…65 V;
Output power - from 40 to 300 Watts (depending on U power supply)
Schematic diagram of the Lanzar V3.1 amplifier:
Pay attention to resistors R3 and R6 - these are current-limiting resistors of parametric stabilizers formed by these resistors and zener diodes VD1 and VD2. The lower the supply voltage, the lower the values of these resistors.
● Supply voltage ±70 Volts – 3.3…3.9 kOhm;
● Supply voltage ±60 Volts – 2.7…3.3 kOhm;
● Supply voltage ±50 Volts – 3.2…2.7 kOhm;
● Supply voltage ±40 Volts – 1.5…2.2 kOhm;
● Supply voltage ±30 Volts – 1…1.5 kOhm;
● Supply voltage ±20 Volts - it is better to choose a different amplifier circuit for assembly.
The value of the constant voltage at the output of the amplifier depends on the rating of R1. In the diagram, the nominal value of R1 is 27 kOhm, you can put 22 kOhm. Often it has to be selected in the range from 15 to 47 kOhm.
2 resistors installed in the emitters of the differential stage (R7, R12 and R9, R13) - the values of these resistors directly depend on how accurately you can select the gains of transistors VT1, VT3 and VT2, VT4. The more accurately the gain factors of these transistors are selected, the lower the value can be used in emitter circuits, and the lower the value of these resistors, the less nonlinear distortion introduced by the differential stage. Resistor values without selecting transistors should be about 82...100 Ohms. If the transistors are selected, the resistor values can be reduced to 10 Ohms.
The value of resistor R14 determines the gain of the amplifier.
The resistor located between the emitters of transistors VT8 and VT9 is rated at 47 Ohms. It is not recommended to change.
Resistors located in the base circuits of the output transistors, their value can be in the range of 1...2.4 Ohms.
Resistors in the emitter circuits of the output transistors - power of at least 5 Watts, nominal value 0.1...0.3 Ohm. Of course, the values of these resistors must be the same.
Diodes VD3 and VD4 are designed for a current of 1...1.5 Amperes (the brand does not matter), the main thing is that they are the same.
At the input, two electrolytic capacitors are connected in series with their positive leads outward; they form a non-polar capacitance. And a film capacitor connected in parallel with them, together with them, creates minimal distortion of the audio signal over the entire frequency range. A similar circuit is found in the feedback circuit of an amplifier.
Capacitor C4 is noise suppressing. The rating can be from 330 to 680 pF.
Capacitors C12 and C13 - nominal 33 pF. They serve to reduce the speed of the amplifier, since without them the rise in the output signal is too large, and the amplifier becomes prone to self-excitation. Exactly the same capacitor is connected in parallel to resistor R25, which determines the gain.
Resistor R13 can also be used to adjust the gain.
Resistors in the base circuit of transistor VT7 - setting the quiescent current of the final stage. VT7 is installed on a radiator with output transistors for thermal stabilization of the quiescent current of the latter. Trimmer resistor – multi-turn type 3296.
Coil - 10 turns of wire with a diameter of 0.8 mm on a mandrel with a diameter of 12 mm.
The amplifier is turned on for the first time after checking the installation for the presence of “snot”. The resistor slider of the quiescent current regulator is in the upper extreme position according to the circuit, this means that the quiescent current of the output stage transistors should be minimal. It is also worth limiting the current developed by the power source; for this, an incandescent lamp of 40...60 Watt is switched on in series with the power transformer. We apply supply voltage to the circuit, and if after a short flash the light goes out, or glows so that the filament is barely visible, then there are no serious errors in the installation. We check the presence of zero at the output of the amplifier and the voltage at the zener diodes VD1 and VD2. Next, turn off the power and remove the incandescent lamp from the circuit. Turn on the power again. We adjust the quiescent current of the output stage with a variable resistor; it should be in the range of 70...100 mA.
Lanzar amplifier circuit board:
There is also an alternative version of the printed circuit board for this amplifier, its appearance is shown in the pictures below (this version of the board has not been tested, so check its correctness before proceeding with its manufacture, errors are possible):
You can download the diagram and both versions of the printed circuit board in LAY format using a direct link from our website. Also in the archive you will find a file in PDF format, from which you will also get a lot of useful information. The download file size is 0.65 Mb.
Photo sent by Alexander (Allroy), Novorossiysk
By chance, I received a “modernized” power amplifier “Oda-UM102S”. The modernization was carried out by an unknown master so severely that only good “meaty” radiators remained alive. So I decided to adapt my new project to them, which smoothly flowed out of the desire to try out a new idea in hardware.
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
How to make L1 I, but if this option bothers anyone, then the coil can be wound on a 2-watt 10-33 Ohm resistor with a wire with a diameter of 0.8 mm in one layer.
VT5, VT6 are equipped with small radiators, which are an aluminum plate 10x20 mm.
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Thank you for your attention!
Igor Kotov, editor-in-chief of Datagor magazine
Thank you for your attention!
Andrey Zelenin,
Kyrgyzstan, Bishkek
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