The article will talk about how to make ULF with your own hands from improvised materials. And preference will be given only to those designs that even a novice radio amateur who has just learned to read electrical circuit diagrams can repeat. But first things first. To begin with, it is worth noting that there are four types of circuits: on lamps, transistors, microcircuits, as well as mixed, which can contain several types of elements. For example, the preamplifier can be assembled on transistors, and the final amplifier on tubes.
Which scheme to choose?
It is worth deciding what you expect from the device and in what area you are going to use it. It depends on which ULF scheme will be used. But in any case, of course, the choice of a modern element base is the most effective solution. Please note that lamp technology has a huge drawback - a massive power supply. And it will be extremely difficult to find transformers now. And if there is no stock of lamps, then if one fails, you will lose your amplifier. Make on ULF lampsdo-it-yourself is quite simple, only the design turns out to be cumbersome.
Transistor designs look more attractive, but they also have a big disadvantage. With sheer circuit complexity, you get very low power. It is likely that you can get a huge printed circuit board, on which the elements are located close to each other, and the power of this entire device is no more than 10 watts. Therefore, the third option remains - the use of microcircuits. Simple, reliable, durable (with proper use).
PCB
You can install it in a small area, so a piece of foil material measuring 30x30 mm is enough for you. But you can also use the so-called fish - textolite with holes for mounting elements and small areas of metal around them. This will be the best solution. Making a simple ULF with your own hands is a matter of a few minutes.
If there is only foil textolite, then you will have to cut grooves on it. They will allow you to make a few patches of copper on a small board. All elements of the amplifier will be mounted on them. Please note that the power supply can be made both separately from the main part of the ULF, and together with it.
Power Amplifier
As a rule, 9-18 volt power is enough for household amplifiers. These are standard voltage values, transformers can be found almost everywhere. The power supply scheme is standard -transformer, four diodes and a capacitor with a capacity of at least 100 microfarads to get rid of the variable component of the supply voltage.
But a lot depends on which ULF scheme will be used in your design. If you plan to assemble a low-power ULF, then you need to look at the datasheet of the microcircuit that you are going to use. Pay special attention to the line in which the supply voltage range is indicated. If a drop to 5 V is acceptable, then it is quite possible to use any charger from the phone.
How to assemble an amplifier
ULF on microcircuits needs additional cooling. Sometimes even low-power structures generate a large amount of heat. Therefore, it is imperative to use aluminum heatsinks for effective cooling.
If you are assembling a powerful ULF with your own hands, then you should carefully consider the issue of cooling. It is possible that additional installation of a cooler is required.
In general, assembling ULF with your own hands should not be difficult. All elements are connected according to the scheme. And after the control check and continuity, power is supplied and the signal source is connected to the input. Of course, the output needs a load - a speaker. With a working chip, the amplifier starts working without settings. It is worth noting that it is best to use the amplifier circuit that is given in the datasheet of the microcircuit. In these typical schemes, everything, even the smallest nuances of the operation of a particular microcircuit, are taken into account. And it will work well only taking into account these nuances. Using the diagrams fromunverified sources, you risk damaging the chip. And sometimes its cost is quite high.
