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 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

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 has 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:

1. Paired transistors are replaced with other pairs. Composing a pair of transistors from two different pairs is unacceptable.
2. VT5/VT6 can be replaced with 2SB649/2SD669. It should be noted that the pinout of these transistors is mirrored relative to the 2SA1837/2SC4793, and when using them, they must be rotated 180 degrees relative to those drawn on the board.
3. VT8/VT9– on 2SC5171/2SA1930
4. VT7– on BD135, BD137
5. Transistors of differential stages ( VT1 andVT3), (VT2 andVT4) it is advisable to select pairs with the smallest beta spread (hFE) using a tester. An accuracy of 10-15% is quite enough. With a strong scatter, a slightly increased level of direct voltage at the output is possible. The process is described by Mikhail (D-Evil) in the FAK on the VP amplifier .

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!

1. IMPORTANT! Before soldering each the part must be checked for serviceability, the resistance of the resistors must be measured to avoid errors in the nominal value, the transistors must be checked with a continuity tester, and so on. It is much more difficult to look for such errors later on the assembled board, so it is better to take your time and check everything. Save A LOT time and nerves.
2. IMPORTANT! Before soldering the trimmer resistor R15, it must be “twisted” so that its total resistance is soldered into the gap in the track, i.e., if you look at the picture above, between the right and middle terminals. all the resistance of the trimmer.
3. Jumpers to avoid accidental short circuit. It is better to do it with insulated wires.
4. Transistors VT7-VT13 are installed on a common radiator through insulating gaskets - mica with thermal paste (for example, KPT-8) or Nomakon. Mica is more preferable. Indicated in the diagram VT8,VT9 in an insulated housing, so their flanges can simply be lubricated with thermal paste. After installation on the radiator, the tester checks the transistor collectors (middle legs) for the absence of short circuits. with radiator.
5. Transistors VT5, VT6 You also need to install it on small radiators - for example, 2 flat plates measuring about 7x3 cm, in general, install whatever you find in the bins, just don’t forget to coat it with thermal paste.
6. For better thermal contact, differential cascade transistors ( VT1 and VT3), (VT2 and VT4) you can also lubricate them with thermal paste and press them together with heat shrink.

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!

In this article I will show my Lanzar amplifier.The amplifier was assembled half a year ago to order, but in the end the customer changed his mind and I abandoned work on it.

I remembered about him only now, when the competition began. The amplifier is almost complete, all that is missing is a couple of field switches in the converter and we need to achieve adequate protection, but everything is ready. Unfortunately, I will not conduct tests of the amplifier in the video, the two main reasons are the lack of a powerful 12 volt power source and the second - the 100 watt test speaker gave up life during the previous tests, the diffuser simply jumped out along with the coil, now I am without a speaker :) for Then I measured the power, at 5 - almost 6 ohms it was 300-310 watts.

One thing that surprises me about this amplifier is that with an output power of almost 300 watts, the output transistors do not burn out, although they were bought on eBay for 100 rubles/pair.

Below is the amplifier circuit

The circuit was taken from the Internet, as was the printed circuit board.

Now let's look at the converter circuit

I drew the circuit myself, here we see a voltage converter on IR2153, the frequency of the converter is 70 kHz, IRF3205 are used as power transistors, 2 pieces per arm.

And – the converter’s power can be supplied (through a fuse, of course) directly to the battery, because the converter will turn on only when 12 volts are supplied from the radio to the REM contact, namely to the power leg of the microcircuit. Here's a clever launch scheme. By the way, the cooler is powered not directly from the battery, but from a separate output of the converter specifically so that it turns on only when the amplifier itself is turned on, and does not spin endlessly, which would greatly reduce its lifespan.

The transformer is wound on two folded rings with a permeability of 2000

The primary winding contains 5 turns per arm with 0.8 mm wire in 10 cores. The main secondary winding has 26+26 turns with the same wire of 4 cores. The low-pass filter power winding contains 8+8 turns of the same wire. The winding for powering the cooler is 8 turns.

At the output we have a bipolar voltage of +- 60 volts to power the amplifier itself and the protection unit, a bipolar stabilized +-15 volt to power the low-pass filter, and a unipolar stabilized 12 volt to power the cooler. All voltages are rectified by diode bridges. The main output is 4 FCF10A40 10 Ampere 400 Volt diodes, they are placed on the radiator. The remaining bridges are built from ultra-fast 1 Amp UF4007 diodes.

There is no low-pass filter or protection circuit, but there are printed circuit boards with all component ratings.

This is what I ended up with

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.

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