We're assembling a homemade low-frequency amplifier

Today it is no longer fashionable to solder different shiny parts on a homemade circuit board, as it was about twenty years ago. However, in our cities there are still circles of radio amateurs, specialized magazines are being issued in offline and online modes.

Why did interest in radio electronics fall sharply? The fact is that in modern stores everything that is required is realized, and there is no need to study anything or search for ways to acquire it.
But not everything is as simple as we would like. On sale there are excellent speakers with active amplifiers and subwoofers, wonderful imported stereo systems and multi-channel mixers with a wide range of possibilities, but there are no low-power low-frequency amplifiers at all . As a rule, they are used to connect instruments at home, so as not to destroy the psyche of neighbors. Buying a device as a part of a powerful device is rather expensive, the rational solution will be the following: a bit of stalling and creating a self-made amplifier without assistance. Fortunately, today it is possible, and my uncle-internet in this with pleasure will help.

The amplifier "assembled on the knee"
Attitude to the self-assembled instruments is somewhat negative today, and the expression "to collect on the knee" is excessively negative. But we will not listen to envious people, but immediately turn to the first stage.
Initially, you must select a scheme. Homemade sound amplifier type ULF can be done on a transistor or chip. The first option is highly discouraged by novice radio amateurs, since semiconductor devices will clutter the board, and the repair of the device will become more complicated. It is best to replace a dozen transistors with one monolithic microcircuit. Such a self-made amplifier will please the eye, it will turn out to be compact, and it will take a little time to assemble it.

To date, the most popular and reliable is the TDA2005 chip. It is already in itself a two-channel ULF, it is enough only to organize power and provide input and output signals. Such a simple homemade amplifier will cost no more than a hundred rubles, along with other details and wires.

The output power of the TDA2005 is between 2 and 6 watts. This is enough for listening to music at home. The list of used parts, their parameters and, in fact, the circuit itself is shown below.

When the device is assembled, it is recommended to screw a small aluminum screen to the chip. Thus, when heated, the heat will dissipate better.
This self-made amplifier is powered from 12 volts. For its implementation, a small power supply unit or an electric adapter with the ability to switch output voltage values is purchased. The current of the device is not more than 2 amps.

To this ULF-amplifier you can connect speakers up to 100 watts. The input of the amplifier can be signaled from a mobile phone, DVD player or computer. At the output, the signal is removed through a standard jack under the headphones.

So, we figured out how to assemble the amplifier in a short time for small money. The rational decision of practical people!