What does the amplifier look like? Sound amplifier from an old TV

They are a thing of the past, and now, in order to assemble any simple amplifier, you no longer have to suffer with calculations and rivet a large printed circuit board.

Now almost all cheap amplifying equipment is made on microcircuits. The most widely used TDA chips for amplifying the audio signal. These are currently used in car radios, active subwoofers, home acoustics, and many other audio amplifiers, and look something like this:



Pros of TDA chips

  1. In order to assemble an amplifier on them, it is enough to supply power, connect speakers and several radio elements.
  2. The dimensions of these microcircuits are quite small, but they will need to be placed on a radiator, otherwise they will get very hot.
  3. They are sold at any radio store. On Ali, something is expensive, if you take it at retail.
  4. They have built-in various protections and other options, such as mute and so on. But according to my observations, the protections do not work very well, so the microcircuits often die either from overheating or from. So it is advisable not to close the microcircuit pins to each other and not to overheat the microcircuit, squeezing all the juice out of it.
  5. Price. I wouldn't say they are very expensive. For the price and functions they perform, they have no equal.

Single-channel amplifier on TDA7396

Let's assemble a simple single-channel amplifier on the TDA7396 chip. At the time of this writing, I took it at a price of 240 rubles. The datasheet for the microcircuit said that this microcircuit can deliver up to 45 watts into a 2 ohm load. That is, if you measure the resistance of the speaker coil and it will be about 2 ohms, then it is quite possible to get a peak power of 45 watts on the speaker.This power is quite enough to arrange a disco in the room not only for yourself, but also for your neighbors and at the same time get a mediocre sound, which, of course, cannot be compared with hi-fi amplifiers.

Here is the pinout of the chip:


We will assemble our amplifier according to the typical scheme that was attached in the datasheet itself:


We feed +Vs to leg 8, and we don’t feed anything to leg 4. So the diagram will look like this:


Vs is the supply voltage. It can be from 8 to 18 volts. “IN+” and “IN-” - here we give a weak sound signal. We hook the speaker to the 5th and 7th legs. We put the sixth leg on the minus.

Here is my flush mount build


I did not use capacitors at the 100nF and 1000uF power input, since I have pure voltage coming from the power supply.

Rocked the speaker with the following parameters:


As you can see, the resistance of the coil is 4 ohms. The frequency band indicates that it is a subwoofer type.

And this is what my sub looks like in a self-made case:


I tried to shoot a video, but the sound on the video is very bad for me. But still, I can say that from the phone at medium power it was already pecking so that the ears were wrapped, although the consumption of the entire circuit in working form was only about 10 watts (we multiply 14.3 by 0.73). In this example, I took the voltage, as in a car, that is, 14.4 Volts, which fits well into our operating range from 8 to 18 Volts.


If you do not have a powerful power source, then it can be assembled according to this scheme.

Do not go in cycles in this chip. These TDA chips, as I said, there are many types. Some of them amplify the stereo signal and can output sound to 4 speakers at once, as is done in car radios. So do not be lazy to rummage through the Internet and find a suitable TDA. After completing the assembly, let your neighbors check out your amplifier by unscrewing the volume knob for the entire balalaika and leaning the powerful speaker against the wall).

But in the article I assembled an amplifier on a TDA2030A chip

It turned out very well, since the TDA2030A has better characteristics than the TDA7396

I will also add, for a change, another circuit from a subscriber whose amplifier on the TDA 1557Q has been working properly for more than 10 years in a row:


Amplifiers on Aliexpress

On Ali, I also found kit kits on TDA. For example, this stereo amplifier is 15 watts per channel and costs $1. This power is enough to hang out with your favorite tracks in the little room


You can buy.

But he's ready right now


Anyway, there are a lot of these amplifier modules on Aliexpress. Click on this link and choose any amplifier you like.

This audio amplifier circuit was created by everyone's favorite British engineer (electronics engineer) Linsley-Hood. The amplifier itself is assembled on only 4 transistors. It looks like an ordinary bass amplifier circuit, but this is only at first glance. An experienced radio amateur will immediately understand that the output stage of the amplifier works in class A. It is ingenious that it is simple and this circuit is proof of that. This is a super-linear circuit where the shape of the output signal does not change, that is, at the output we get the same waveform as at the input, but already amplified. The scheme is better known as JLH − class A ultra-linear amplifier, and today I decided to present it to you, although the scheme is far from new. Any ordinary radio amateur can assemble this sound amplifier with his own hands, due to the absence of microcircuits in the design, which makes it more affordable.

How to make a speaker amplifier

Sound amplifier circuit

In my case, only domestic transistors were used, since it was not easy to find with imported ones, and even standard circuit transistors. The output stage is built on powerful domestic transistors of the KT803 series - it is with them that the sound seems better. To build up the output stage, a medium-power transistor of the KT801 series was used (it was difficult to find). All transistors can be replaced with others (KT805 or 819 can be used in the output stage). Changes are not critical.


Advice: who decides to taste this homemade sound amplifier - use germanium transistors, they sound better (IMHO). Several versions of this amp have been made, they all sound… divine, I can't find any other words.

The power of the presented circuit is not more than 15 watts(plus minus), current consumption 2 Amperes (sometimes a little more). The output stage transistors will get warm even without a signal being applied to the input of the amplifier. Strange phenomenon, isn't it? But for class amplifiers. And, this is quite a normal phenomenon, a large quiescent current is the hallmark of literally all known circuits of this class.


The video shows the operation of the amplifier itself, connected to the speakers. Please note that the video was filmed on a mobile phone, but the sound quality can be judged in this way. To test any amplifier, you just need to listen to just one melody - Beethoven's "Fur Elise". After turning it on, it becomes clear what kind of amplifier is in front of you.

90% of microcircuit amplifiers will not pass the test, the sound will be “broken off”, wheezing and distortion can be observed at high frequencies. But the above does not apply to John Linsley's circuit, the ultra-linearity of the circuit allows you to completely repeat the shape of the input signal, thus obtaining only pure gain and a sinusoid at the output.

The expression "Sisyphean labor" is known to one hundred percent of radio amateurs. For success, a positive outcome of a dozen (even more) completed works is needed, in order for all the work to go to waste, one single minor oversight is enough. And so sometimes you want something to work out, especially for a novice electronics lover who has not yet mastered the entire arsenal of skills and abilities. However, there are no hopeless situations. On boards that previously belonged to some electronic devices, you can always find something that, after some minor refinement, will become a separate, properly functioning device. So on the board that was once part of the television receiver can be found.

You don’t even need to look for it, it “gets into your eyes” itself. TDA chip with a protruding "scallop" - a cooling radiator and the corresponding "strapping" of electronic components. Before cutting out the desired piece of textolite with details with a hacksaw, it is imperative to obtain a schematic diagram.

ULF circuit on the TDA1013 chip

Having carefully studied the object of interest, solder the parts of adjacent nodes around the perimeter. Not only are they not needed, they get in the way.

And now, finally, the right thing has been obtained. It remains to solder a few wires. To understand which ones and where, we find the passport of that microcircuit TDA1013. Need a wiring diagram.

Discuss the article TV SOUND AMPLIFIER


Hello to all DIYers, as usual, every novice radio amateur has an idea to do something, but the first thing that usually comes to mind is to assemble an amplifier that will be easy to assemble and does not require financial costs. That is why I decided to assemble an amplifier, the main “heart” of which can be removed from an unnecessary or old TV, I will tell you how to make it in this article.

To assemble a sound amplifier, we need to prepare all the necessary materials, these are:
TV, unnecessary or just old, please note that you will not find such an amplifier on TVs made in the USSR.
Soldering iron and everything you need to use it, stand, solder and flux.
Wires are perfect from a computer power supply.
Plug for tulips, such can be found in the radio, DVD player or music center.
A clip for the wires through which the sound amplified by the amplifier will go is also found in most music systems.
Cooling radiator, I removed from an old vinyl player.
Power supply from a laptop, the insides will not be needed, but only the case.
Pliers.
Two-pin plug, according to the diameter of the contact, it fits into the block from the PC.
Stationery knife for making holes.

After all the details are ready and you have definitely decided that the moment has come when you can make a simple amplifier, you can proceed to the step-by-step assembly.

Step one. As usual, the TV is made in a plastic case, we remove it to get to the board. Attention, before disassembling, remove the plug from the outlet, it is not in vain that high voltage is written on the TV. After the cover is removed, you can see the board, there is a radiator on it, which is usually made in the form of sheet aluminum, you need to cut the board with metal scissors or with pliers, leave more than 10 cm around the microcircuit, since the board should remain working.


Step two. In order to make a sound amplifier from the “insides” of the TV, you need to find information on the Internet on the microcircuit, the marking of which is written on it in white letters with a set of numbers, in this case it is the TDA 2611 microcircuit, the data about it is in the datasheet and the switching circuit, see on the picture.


It is according to the scheme that we will give the microcircuit a second life.

Further assembly will take place using the circuit shown in the picture. Using a soldering iron, we solder a pre-tinned red wire to the 1st leg of the microcircuit, the countdown goes to the right, this wire is a power plus, for a minus we take the black wire, which we solder to the 6th leg, these two wires are fixed on the plug.


We figured out the power, now you need to make a sound input, which can be supplied from any player or phone using a jack plug adapter on one side and a pair of tulips on the other. We solder the inputs for these tulips to the 7th leg through a resistor fixed on the board at the entrance and the 6th leg.


We make the sound output on the clamps, the wires of which we connect to the track of the 2nd leg of the microcircuit that goes after the capacitor by 220 microfarads, the second contact goes, as in most cases, to the minuses.


Part of the amplifier electronics is ready, now we need a good noble case with cooling. Without thinking twice, I opted for a power supply for charging a laptop, the case from it seemed to me to be good. Well, let's get started. To begin with, we will open up its contents and, using a clerical knife, cut out holes for tulips and food on one side and on the other for sound output.







All plugs are attached with hot glue. At the end, it is necessary to screw the amplifier chip onto the radiator and also fix it with hot glue.

Factory audio amplification devices are expensive and may not be powerful enough. Looking at the photos of homemade sound amplifiers, it is obvious that they outwardly are in no way inferior to finished products. In addition, their manufacture on their own does not require special skills and high material costs.

Device basis

Beginning radio amateurs first of all ask themselves the question: what can a simple sound amplifier be assembled from at home. The operation of the device is based on transistors or microcircuits, or a rare option is possible - on lamps. Let's take a closer look at each of them.

Microcircuits

A TDA series chip and a similar one can be purchased in stores or use a chip from an unnecessary TV.

Using car amplifier chips with a 12 volt power supply, it is very easy to achieve high-quality sound without the use of special skills and with a minimum of details.

transistors

Advantages of transistors in low power consumption. The device produces excellent sound performance, is easily integrated into any technique and does not require additional configuration. In addition, there is no need to search and use complex microcircuits.

Lamps

To date, the outdated assembly method based on tubes gives high-quality sound, but has several disadvantages:

  • increased energy intensity
  • dimensions
  • cost of components

Recommendations for the correct assembly of a sound amplifier with your own hands

A homemade sound quality amplification device based on TDA series chips and their analogues generates a lot of heat. For cooling, you need a radiator grill of a suitable size, depending on the model of the microcircuit itself and the power of the amplifier. In the case you need to provide a place for it.


The advantage of this DIY device is its low power consumption, which allows it to be used in cars by connecting it to a battery, as well as on the road or at home using a battery. The power consumption depends on the required degree of signal amplification. Some manufactured models require a voltage of only 3 volts.

We apply a serious and responsible approach to the assembly of the sound amplifier in order to avoid short circuits and failure of components.

Necessary materials

During the assembly process, you will need the following tools and components:

  • chip
  • frame
  • capacitors
  • power unit
  • plug
  • button-switch
  • wires
  • cooling radiator
  • screws
  • hot melt and thermal paste
  • soldering iron and rosin

Diagrams and instructions for making an amplifier at home

Each circuit is unique and depends on the sound source (old or modern digital technology), power supply, estimated final dimensions. It is assembled on a printed circuit board, which will make the device compact and more convenient. In the assembly process, you can not do without a soldering iron or soldering station.

The scheme of the British John Linsley - Hood, is based on four transistors without microcircuits. It allows you to similarly repeat the shape of the input signal, resulting in only a pure gain and a sinusoid at the output.

The simplest and most common option for manufacturing a single-channel amplifier is to use a microcircuit, supplemented with resistors and capacitors, as the basis.

Algorithm of actions for manufacturing

  • install radio components on the printed circuit board, taking into account the polarity
  • assemble the body (providing space for additional parts, for example, a radiator grill)


It is acceptable to use a ready-made case or create it yourself, as well as install the board in the speaker case.

  • run the device in test mode (detect and eliminate faults in case of occurrence)
  • assembly of the amplifier (connection to the power supply and other components)

Note!

Do-it-yourself home and car amplifiers

At home, powerful sound is often lacking when watching movies on a laptop or listening to music on headphones. Consider how to make a sound amplifier with your own hands.

For laptop

The sound wave amplifier must take into account the power of external speakers up to 2 watts and the resistance of the windings up to 4 ohms.

Assembly accessories:

  • 9 volt power supply
  • printed circuit board
  • chip TDA 7231
  • frame
  • non-polar capacitor 0.1 uF - 2 pcs
  • polar capacitor 100 uF
  • polar capacitor 220 uF
  • polar capacitor 470 uF
  • resistor constant 10 kΩ m 4.7 ohm
  • on/off switch
  • entry socket

Manufacturing scheme

The algorithm of assembly actions is selected depending on the selected scheme. It is necessary to take into account the appropriate size of the cooling radiator so that the operating temperature inside the case does not rise above 50 degrees Celsius. When using a laptop outdoors, you need to provide holes in the case for air access.

for car radio

It is possible to assemble an amplifier for a car radio on a common TDA8569Q chip. Its characteristics:

  • supply voltage 6-18 volts
  • input power 25 watts per channel into 4 ohms and 40 watts per channel into 2 ohms
  • frequency range 20-20000 Hz

Note!

It is imperative to provide, in addition to the circuit, a filter against interference created by the operation of the car.


First, draw the printed circuit board, then drill holes in it. Then the board must be etched with ferric chloride. After tinning and soldering all the details of the microcircuit. The feed paths will need to be thickly soldered to avoid power additives. Provide a cooling system using a cooler or radiator grille.

At the end of the assembly, it is necessary to make a filter from the interference of the ignition system and poor sound insulation according to the following scheme: on a ferrite ring with a diameter of 20 mm, wind a choke with a wire with a cross section of 1-1.5 mm in 5 turns.

Assembling a device to improve sound quality at home is not difficult. The main thing is to decide on the circuit and have at hand all the components from which you can easily assemble a simple sound amplifier.

DIY sound amplifier photo

Note!