How to properly make tube amplifiers with your own hands

In the article you will learn how to make tube amplifiers with your own hands from improvised materials. It's no secret that the tube sound is the most beautiful, its fans will exist at all times, despite the fact that the market is full of a lot of offers of small-size equipment on transistors and microcircuits. Consider in more detail what you should consider when manufacturing a tube amplifier.

Nutrition is the main difficulty

Yes, the power supply can cause problems, since you will need two AC voltage values: 6.3 V for power filament and 150 V for lamp anodes. The very first thing you need to find out for yourself is the power of the future design. This affects the power of the transformer for the power supply. Please note that the transformer must have three windings. Without such power supply it is impossible to make tube amplifiers by your own hands.

In addition to the above secondary, there must also be a network (primary). It should contain as many turns as possible so that the transformer operates in normal mode. And even at a considerable load (and jumps in the voltage up to 250 V), the winding should not overheat. Of course, the dimensions of the power supply will be rather large due to the large size of the transformer.

Rectifier

You need to make a rectifier to get a minimum of + 150 volts DC voltage. To do this, use a bridge circuit to connect the diodes. The design of the power supply can use diodes D226. If you want to make high reliability, then use the D219 (they have a maximum operating current of 10 amperes). If you make tube amplifiers by yourself, then observe the safety rules.

Not bad work in power supplies diode assemblies. You only need to choose those that are able to function normally at voltages up to 300 volts. Pay special attention to filtering the output DC voltage - install 3-4 electrolytic capacitors connected in parallel. The capacitance of each must be at least 50 uF, the supply voltage is more than 300 V.

Preamplifier circuit on lamps

So, now closer to the circuit itself. If you make a tube guitar amplifier yourself, or to play music, you need to understand that the most important thing is safety and reliability. The most common circuits contain one or two stages of a preamplifier and one end. Preliminary are built on triodes. Since there are radio tubes, in which there are two triodes in one socket, you can save a little space during installation.

And now about what elements contain tube amplifiers. With their own hands will have to collect all in a single design. For a lamp in a preamplifier, it is best to use 6Н2П, 6Н23П, 6Н1П. And, despite the fact that all these lamps are analogues to each other, 6N23P sounds much more pleasant. This lamp can be found in the block PTK (switch of television channels) of old black and white TVs such as "Record", "Spring-308", etc.

The final amplifier stage

The output lamp is usually 6P14P, 6P3S, G-807. And the first will be the most miniature, but the last two are quite impressive sizes. And at Г-807 anode and at all in the top part of a cylinder. Pay attention to the fact that in the tube ULF necessarily need to use a transformer to connect the acoustics. Without such a matching transformer, you can not make a tube amplifier yourself.

Transformers of TCEs used in the vertical scanning work fine as output. Its primary winding is switched between the plus of the power supply and the anode of the output lamp. In parallel to the windings, a capacitor is connected. And it is very important to choose the right one! First, it must be paper (such as MBM). Secondly, its capacity should be at least 3300 pF. Do not use electrolytic or ceramic.

Adjustments and stereo sound

Make stereo sound is very easy. It is enough just to make two identical amplifiers. You can find in the old Soviet technique a stereo tube amplifier. With your hands, you can repeat the design. But you need to consider some of the features:

1. The volume control is connected directly to the input of the amplifier. A variable resistor, which is used for it, needs to be chosen such that in one housing there are two elements on the axis. In other words, so that when the knob is rotated, the resistance of two resistors changes at once.
2. Similar requirements also apply to the frequency controller. It turns on the anode circuit of the first triode of the preamplifier.

Enclosure for amplifier

If you make a tube guitar amplifier with your own hands, then use a metal case makes sense. He will not be afraid of strikes and other minor upheavals. But if you make an amplifier for use at home, for example, to connect to a player, a computer, then it's more reasonable to use a case made of wood. But you need to take into account that the power transformer should be mounted to the body with rubber gaskets. With their help, vibration is reduced.

Much depends on what will be the case of the tube amplifier. With their hands, many craftsmen make cases of sheet aluminum. If the lamp will be affected even by small vibrations, its grid will begin to oscillate. And these fluctuations will begin to increase, and the result is a buzz in the speakers. Also, you need to make a common bus, which must pass near all the lamps that make up the design. All the wires through which the signal goes must be maximally screened - this will get rid of various kinds of interference.

Diagrams with transistors

And another interesting design is tube-transistor amplifiers. You can do it with your own hands literally in the evening. But the lamp constructions, as a rule, are made by hinged installation. It turns out to be the most convenient and simple. And in case if transistors are used, you need to use printed editing. In addition, a voltage of 9 or 12 volts is required to power the transistor stages. And transistors are used only to build a preliminary cascade of amplification. In other words, you will only have one lamp - in the output stage (or two, if it's a stereo version).