The circuit of the sound amplifier is the simplest. How to make a sound amplifier yourself

In this article, we will consider the amplifier circuit for domestic use. Depending on which sphere the amplifier will be used (it is also called the ULF low-frequency amplifier ), it will have different dimensions and complexity of circuit design. In the article, three types of amplifiers - on transistors, microcircuits and lamps - will be touched at once. And it's worth starting with the latter.

Lamp ULF

These can often be found in the old equipment - televisions, radios. Despite the obsolescence, this technique is still popular with music lovers. There is an opinion that the tube sound is much cleaner and more beautiful than the "digitized" one. It is quite possible, in any case, such an effect, as from lamps, is not achieved using transistor circuits. It is worth noting that the amplifier circuit of the sound (the simplest, using lamps) can be realized on a triode alone.

In this case, the signal must be fed to the radio tube grid. The bias voltage is applied to the cathode - it is corrected by selecting the resistance in the circuit. Supply voltage (above 150 volts) is applied to the anode through the capacitor and the primary winding of the transformer. Accordingly, the secondary winding is connected to the dynamics. But this is a simple circuit, but in practice it is often used two- or three-stage designs, in which there is a preliminary and final amplifier (on high-power lamps).

Disadvantages and advantages of lamp constructions

What is the disadvantage of lamp technology? It was mentioned above that the anode voltage should be above 150 volts. In addition to this, it is necessary to have an AC voltage of 6.3 V for feeding the filament of the lamps. Sometimes 12.6 V is required, since there are lamps with such a heating voltage. Hence the conclusion is a huge scheme of the power supply unit, the need to use massive transformers.

But there are advantages that distinguish lamp technology from transistor: simplicity of installation, durability, it is almost impossible to disable the whole circuit. Unless you need to break a bulb of a lamp to break it. What can not be said about transistors - an excessively heated soldering tip or statics can easily destroy the structure of the transition. The same problem with microcircuits.

Transistor circuits

Above is a diagram of a sound amplifier on transistors. As you can see, it is quite complex - a large number of components are used that allow the whole system to work. But if you break them into small parts, it turns out that not everything is so difficult. And the whole circuit works in much the same way as the one described above on the vacuum triode. In fact, a semiconductor transistor is nothing more than a triode.

The simplest design is a circuit on a single semiconductor, on the base of which three voltages are supplied at once: from positive power through positive resistance and from common wire negative, and also from the signal source. The amplified signal from the collector is removed. The above is an example of a sound amplifier circuit (the simplest one on transistors). It is not used in its pure form.

Microchips

A much more modern and high-quality amplifier will be on chips. Fortunately for today their great variety. The simplest circuit of the audio amplifier on the chip contains an extremely small number of elements. And to make independently a good ULF can any person who knows how to handle the soldering iron more or less tolerably. As a rule, the chips contain a couple of capacitors and resistances.

All other elements necessary for work are available in the crystal itself. But the most important thing is food. For some designs, you need to use bipolar power supplies. Often the problem arises precisely in them. The chips that need such power, for example, are quite difficult to use for making an automotive amplifier.

Useful "lotions"

Since the talk about amplifiers on microcircuits has begun, it will be superfluous to mention that they can be used with timbrocks. Specifically for such devices are manufactured microcircuits. They contain all the necessary components, it remains only to properly mount the entire device.

And you will have the opportunity to adjust the timbre of the music. Coupled with the LED EQ, it will not only be convenient, but also a beautiful means of visualizing the sound. And the most interesting for car audio enthusiasts is, of course, the possibility of connecting a subwoofer. But it's worth devoting a separate section, because the topic is interesting and informative.

A subwoofer is easy

To connect a subwoofer, you need to make a separate mono amplifier. If you look at the industrial designs of amplifiers, then in one case they have a stereo and mono amplifiers. The first connects to the speakers, and the second - to the subwoofer. And in the second there is a small feature - the input is a low-pass filter. Depending on the price category, this filter can be adjustable or not. To assemble a sound amplifier with your own hands, the circuit of which is executed on microcircuits, it is possible in a matter of minutes, since nothing is complicated in this.

The simplest LPF is a few resistors and capacitors connected according to the scheme given above. When this circuit is turned on, a signal with a certain frequency in the range of 30-60 Hertz is applied to the input of the amplifier. It is this frequency that is amplified by the ULF and transmitted to the woofer. It should be noted that at the input of the low-pass filter you need to set the volume control.

Advantages of modern amplifiers on microcircuits

Having considered all possible types of amplifiers, we can conclude: the most qualitative and simple ones are manufactured only on a modern element base. A lot of microcircuits are produced for low-frequency amplifiers. As an example, we can cite the ULF of the TDA type with various numerical designations.

They are used almost everywhere, since there are both low-power and high-power microcircuits. For example, for portable computer speakers it is best to use chips that have a power of not more than 2-3 watts. But for automotive technology or home theater acoustics, it is desirable to use chips with a power of more than 30 watts. But pay attention to the fact that power amplifiers need sound protection. The circuits must contain a fuse that will protect against short circuit in the circuit.

Plus, and that does not require a massive power supply, so you can easily use a ready, for example, from a laptop, PC, old MFU (for new, as a rule, the power supply is inside). The ease of installation is something that is important for beginner hams. The only thing that is required for such devices is quality cooling. If it's a powerful technique, you'll have to install a forced one-or a few coolers on the radiator.