There is a lot of controversy about the advantages and disadvantages of tube circuits for low (audio) frequency amplifiers. There are, just the same, whole separate currents of tube sound, with their gurus and adepts. "Only lamps, no semiconductors", "hybrid", "single-ended", "fans of transformers (inter-stage)" and hybrids and subspecies. This is about self-made people, who in any case deserve respect. There are still those for whom fooling their neighbor is a profession. It's really bad there. Of course, there are exceptions everywhere.

Let's not touch on "theology" now, but let's see what we managed to do from, literally, pasture trash.

Perhaps it’s worth starting with the fact that we came to the Perm Territory to look for a place to live, mainly with the most necessary things and radio components were not among them. Fortunately, in the city there was a shop selling radio components, with a peculiar assortment, however, what was found was for happiness. The radio elements required for a tube amplifier are somewhat specific, this is not counting the radio tubes themselves. In a word, having brainwashed, he advertised in the local newspaper for the purchase tube radio. They called a lot, gave a few just like that, with the condition “pick-from-garage-yourself”. There were already four pieces, then the relatives rebelled, and it was embarrassing to insist - we then temporarily lived with our parents, and I made with my grandmother in the private sector. Fortunately, the two radios turned out to have very close internals - a typical 6P14 bass amplifier circuit, and the power supply is the same. "Our Alena Igorevna has such a typical, typical appearance."

The first treacherous thought, which was hardly smothered with a pillow, was simply to take and transfer these amplifier scarves to a separate box and ... and that's it. But firstly, it would not be too aesthetically pleasing (But what about the main highlight - the lamps outside? Show off, of course, but it’s beautiful after all). Yes, on printed circuit boards - well, no. In a word, it was decided to give up the easy way, tea is not the first time we smell rosin! So that everything is like with people ... (singing under his breath) everything is like with people. Yes, hmm, well, I laid out the lamps pulled from the radio on a workbench on a rag, sketched out a schematic, a power supply, so that all voltages are stabilized, that's all. 6P14 output lamps, triode-pentode switching, output transformers, like TVZ 1-9, 6N2P input stage, but left the approval for later, after experiments.

We have never seen decent lamp ceramic panels in the store, I had to get out.

High side walls, only partly for simplicity. Largely for convenience - it does not badly protect fragile and breaking radio tubes, and given the upcoming construction site in the village, it is not at all clear where the device will be dragged. Again, it’s very convenient to set up and redo it - it turned it over and stands as if rooted to the spot, and you don’t need to pull out the lamps either - solder, measure, turn on as much as you like.

Radiator on top for stabilizers, high-voltage and incandescent. Rectifiers for them in the basement of the chassis.

The body is disassembled, putty, sanding, a couple of coats of paint.

Assembly of the case is white.
Mounted power on toggle switches (heat and delayed anode), power indicators on neon bulbs, lamp panels, output stage mode switches - triode-pentode, and on feedback.

Rectifiers are mounted in the basement, a fuse is on the back wall in the fittings, everything is connected, we carefully check the operation of the finished piece of the circuit directly from the network. Lamps stick out for entourage.
Everything works, cheers.

Queue behind the power transformer. This one, from the same radio. The power should be sufficient. The casing was removed from the magnetic circuit, four studs from long M6 bolts were soldered to it. For installation sideways in a kind of lying position, so that all the wires are in the basement of the chassis. I boiled the coil in varnish so that it would not buzz.

High-voltage rectifiers have been mounted and already tested, there are already four of them - for each cascade of two channels, its own. Each diode is shunted with a film capacitance against switching interference.

Electrolytic capacitors are here, including those from stabilizers. The stabilizers themselves will be on the top of the radiator.
Power on toggle switches and neon indicator lights are connected. You can see the signal sockets and the shielded cable to the first stage.

Plank, no, not Picatinny - Mazaya. Contact. It will be mounted on the screws of the transformer inside the case. The diodes of the filament rectifier of all lamps are conveniently soldered on it. Stabilizers, again outside on a common radiator.

Stabilizer +5 volts. With USB socket. For the convenience of the MP3 player. So as not to run around looking for charging or a computer. The usual 7805, in the classic inclusion - two electrolytic, two ceramic capacitors. Powered by filament rectifier.

Oh, the transformer is in place. Charging too. Contact strips are crammed onto the fasteners of the transformer, three diode bridges with electrolytes are soldered to them, charging for the MP3-shnik is turned on.

Scarf with stabilizers. High-voltage on discrete elements, three filament stabilizers in the middle - on 7806, plus, one or two (pick up) diodes in a common output.

On the other side of the board are power elements.

And upside down, to press them with their backs to the radiator. The payment is also made a few original way- in the same manner as with SMD elements, so that there are no tracks or leads on the side of the radiator. Still high voltage.

Here's the way.

From above it is clear a cover, so that fingers do not climb into high voltage. The radiator is standard, needle-shaped, the cover is made of galvanized steel roofing 0.5mm.

BP testing. Connections between the rectifier and the stabilizer on a live thread.

The hardest part is putting it in place and installing it. Radiator with stabilizers on the other side of the chassis. All wires collected in four bundles are threaded into the holes and led to the rectifier. Tweezers, with a bit of patience and care. Then the main fun begins - to look with a tester for which end of the wire and connect according to two schemes, so that nothing extra sticks out, and so that "and look, do not confuse ... Kutuzov." Otherwise, the salute can be noble, we swam, we know.

These are the amplification cascades themselves, their own person, so to speak. Well, just like people. Automatic bias, interstage capacitors like fluoroplastic, let's be curious.

Output transformers.

It is clear from radio receivers that they are boiled in wax with paraffin, the core is hot tightened in a vice through a strip of gum - so that the non-magnetic gap in each layer of iron is the same and minimal. When disassembling and assembling, we do not lose a strip of paper for a non-magnetic gap.

And in an improvised casing from a condensed can.

Fill with wax, or neutral sealant, or epoxy, if you don't mind.

Output transformers in place.

Listening in the grandmother's greenhouse, where there is more space. What, I like it.

The acoustics were like this, the acoustic design is a “closed case”, it plays well, but the sensitivity is not enough, you have to mainly turn on the output stage with a pentode.

This is with a shroud on the radiator.

After working for some time, one of the output transformers burned out, I had to redo it for others.

Especially for the competition from Aka Kasyan and the site site.

Once again I congratulate Ak Kasyan's channel on his birthday :)

In this article, I would like to talk about tube sound and my crafts from tube radios.

We live in the 21st century and we all know that tubes are dying out and they are not used anywhere except in tube amplifiers, but this luxury (I mean factory production) can only be afforded by "elite" people. But there are such wonderful people as radio amateurs, well, or lovers of tube sound, because as they say - "It is worth hearing the tube sound once and you won’t pull it off after", but only those who are deep in their youth when they first appeared are fond of this delicate work. transistors remained on the side of the tubes, or, in our time, they fell in love with the tube sound. But after all, they still think that only people of the older generation are fond of the direction of tube amplifiers, and indeed radio engineering in general. In fact, this is by no means true, and in this article I will try to dispel this judgment. And so, it's time to introduce myself, I'm a beginner radio amateur, my name is Danil, I'm 14 years old, and I'm from the city of Voronezh. Usually, after I say this phrase, everyone immediately stops taking me and my hobby seriously. But there were people who could support me. When I shot my first video, Aka Kasyan commented on it, which I was infinitely happy about, I was also happy about Mikhail's support. And then I realized that since Aka responded positively, then I need to continue.

It was summer and I decided to take on something more difficult for me, and it was a tube amplifier. At first I went deep into studying the theory of tube sound, read a lot, watched videos and studied. When I already had "basic knowledge" I started looking for what kind of amplifier I would assemble, it took a lot of time, but I decided to start with a simple single ended amplifier on 3 lamps (two 6P14P and 6N2P).

It seems like I decided what I would do, but ... It was difficult to find the details, and then I realized that I needed to find an old tube TV. It also took a long time to find him. But after several weeks of searching, I found a TV that was perfect for the amplifier. Record B312.

When they said that the black-and-white record was not working, it was not a pity to remove the lamps. I took off the lamps, capacitors (they were in good condition), a couple of resistors and three transformers - power, TVK and TV-ZSh (See Fig. 3.1, 3.2).

I bought the missing elements, and again there was a problem. Everything was enough for the first channel, but the second one needed a couple more trances - TVK and TV-ZSh, where TVK played the role of a power choke, and TV-ZSh was an output transformer. Well, I coped with this problem and have already gone to extremes by buying a transformer. In the meantime, the second month of summer is coming, yes, I have been searching for so long. Well, then it was necessary to deal with the amplifier case, I found the power supply case from the Soviet logic and decided to be creative, of course it didn’t work out very well, but I think it will do for the first time. This frame from BP served as the basis (See Fig. 1). I made the lower base from a laminate board, and the top cover also from it, for the sidewalls I also made lining from a laminate, but already lighter.

Now for the assembly: I installed the power transformer at the back, blocking it with a flap from the iron cover of the PSU (it turned out to be a kind of screen). Inside I installed a diode bridge of her407 diodes, two anode chokes and sound transformers (See Fig. 4.1, 4.2). Next, the upper board of the laminate was adjusted to the body and the fresco was removed, including for the panels of lamps with conders that I installed on this board (See Fig. 2). Now he began to assemble and solder the elements, spread the ground. I soldered shielded Soviet wires to the input. Incandescence, by the way, is also from Soviet wires (See the remaining pictures at the bottom of the article).

They are part of the equipment management system. These devices are currently actively used for acoustics. You can make a model for headphones yourself. However, there are complex amplifiers based on output transformers. They are intended mainly for speakers of various capacities.

The important parameters of the models include the frequency, as well as the sensitivity of the equipment. Depending on the power of the power supplies, the output voltage indicator varies. In order to understand in more detail this issue, you need to consider the device of a simple amplifier.

Amplifier circuit

A simple tube amplifier consists of a capacitor, a power supply, and resistors. Transistors in devices are often used in the orthogonal type. Directly lamps are applied at 6 watts. Regulators for models are selected as push-button and rotary type. Modulators in amplifiers are mainly pulsed, but code modifications also exist. To increase the frequency of the device, elements such as spark gaps are used. Some models have thyristors. They lower the output voltage quite a lot. In this case, the capacitors do not experience large overloads. Cassette regulators in models of this type rarely used.

Single cycle models

A single-cycle tube amplifier is used for the power of which does not exceed 20 watts. V this case transformers, as a rule, are applied output type. Field capacitors are often used directly. In this case, the lamps can be safely selected for 15 watts. The sensitivity of such devices is highly dependent on resistors. As a rule, they are installed on a single-ended tube amplifier at the beginning of the circuit of an orthogonal type.

Thyristors are never used in such models. This is due to the fact that the resistance in the circuit is quite variable. It is also important to note that the voltage should be regulated using a controller. Acoustics for tube amplifier connected via a two-wire port. The modulator for models is most often used precisely contact. On average, the negative resistance parameter is at the level of 50 ohms. It is also important to note that sensitivity is greatly reduced in amplifiers when copper conductors are used.

Two-stroke modifications

It is very difficult to make a push-pull tube amplifier with your own hands. Step-by-step instruction in this regard will be very useful. For assembly, the transformer will need an output type. Resistors for push-pull tube amplifiers are easiest to install single-pole. Two capacitors are required at the input. Negative resistance in the circuit they are required to withstand at least 60 ohms. In this case, the sensitivity of the devices can reach up to 3 microns.

Trimmer resistors are used to minimize glitches in modulators. Conventional field capacitors are installed at the output of the system. Power supplies for push-pull tube amplifiers are suitable even at 30 V. Cassette regulators are almost never used in such devices. The input voltage parameter in the amplifiers is on average 15 V. The oscillation amplitude in this case depends on the signal frequency.

Hybrid modifications

Hybrid lamps are a set of output transformer and half-duplex resistors. In order to assemble the model yourself, you will need a 40 V power supply. Directly at the input of the circuit, orthogonal-type resistors are used. They must withstand negative resistance at the level of 55 ohms. In this case, it is more expedient to install thyristors behind the output transformer.

Lamps are soldered in sequential order. The frequency of the model depends on the amplitude of the magnetic oscillations. The output voltage parameter in the devices can be easily adjusted using the controller. After installing orthogonal resistors, a power supply is installed on tube sound amplifiers. In this case, the throttle must be directly connected to the controller. Acoustics for a tube amplifier must be connected through a two-wire port. At the last stage of assembly, the output voltage of the transformer should be checked. For normal operation of the system, this indicator should not exceed 15 V.

Features of low-frequency modifications

It is quite difficult to make a low-frequency tube amplifier with your own hands. Step by step instructions can help a lot. Many experts recommend starting with the installation of a transformer. In this case, field-type resistors will be required. Their conductivity is good, and they are able to serve for quite a long time. At the input of the circuit, it is important to solder the capacitor. In this case, an orthogonal type model will work well. At the next stage, it is more expedient to deal directly with the controller to adjust the device.

In some cases, it is selected as a rotary type. The minimum frequency should be set at around 500 Hz. The lamps in this case are soldered in sequential order. To connect the transformer to the controller, it is better to use a coaxial cable. To test the equipment, the output voltage parameter is first measured. In this case, it is important to consider the power of the power supply. Most often, it is selected at 20 V. In this situation, the negative resistance parameter should not exceed 45 ohms.

High frequency models

High-frequency tube power amplifiers belong to the class of push-pull modifications. Their difference lies in the presence of power transformers. All this is necessary to increase the conductivity of the signal. The parameter of the maximum frequency of devices is capable of reaching up to 500 Hz. In this situation, it is more expedient to start assembling the model with the installation of a transformer.

The panel for this can be selected wooden. In this case, the controller must be installed on a lining. In this case, the output voltage can always be checked with a tester. The block is directly used in a 30 V circuit. In this situation, the beam transistors are soldered. They must withstand negative resistance in the system at least 43 ohms. All this will allow you to easily adjust the frequency of the equipment.

The lamps in this case are soldered in sequential order. Capacitors are used both orthogonal and capacitive types. In this situation, a lot depends on the type of controller. If we consider push-button modifications, then we cannot do without a thyristor. With rotary controls, a conventional modulator can be used.

Resistive Load Models

It is very difficult to make this type. Step-by-step instructions in this regard will be very useful. Many experts advise stacking an amplifier based on electrolytic capacitors. It is important to start directly assembling the model with the installation of a transformer. The lamps in this case are soldered in sequential order.

Resistors in models use beam type. However, orthogonal analogs are installed at the input of the circuit. Zener diodes in this situation are used if the power supply is available at 30 V. Otherwise, the modulator copes well with overloads in the network. The controller is connected in the amplifier behind the transformer. Comparators are used to increase the sensitivity of the model. The minimum frequency of the element must be 300 Hz. In turn, the negative resistance indicator should not exceed 50 ohms.

Resonant Load Amplifiers

Models of this type are very common today. The transformer for the tube amplifier must be selected power. It should also be borne in mind that controllers should only be used in cassette type. Directly modulators are installed with expanders. All this gives a significant increase in signal conductivity.

The sensitivity of the model in amplifiers depends on the types of resistors. If we talk about a 20 V power supply, then it should be selected of an orthogonal type. Otherwise, preference can be safely given to single-contact analogues. At the same time, field resistors will not be able to provide high frequency. The easiest way to regulate fluctuations in the network is through thyristors. In this case, the output voltage in the system should not exceed 15 V.

Step-down transformer model

On a step-down transformer, it is quite difficult to make a tube amplifier with your own hands. Step by step instructions can help a lot. It is best to use orthogonal resistors for the amplifier in this situation. However, it is important to start assembling the model with the installation of the power supply. Then the lamps should be connected to the panel. In this case, capacitors can be used capacitive. They must keep negative resistance at 33 ohms. All this will allow to stabilize the frequency at small overloads. Thyristors are used very rarely in circuits of this type. However, if we talk about high-frequency models, then they will be appropriate.

Use of power transformers

You can create an amplifier with only if you find a high-quality comparator. Also in this situation, you can not do without trimmer type resistors. It is recommended to start assembling the model from the panel. Lamps should be installed in sequential order. The power supply in this situation must be connected directly to the inductor.

The negative resistance in the circuit should not exceed 55 ohms. In this case, the output voltage depends on the power of the power supply. Modulators in such devices are available with switches. All this allows you to quickly reduce the frequency when the load on the capacitors increases dramatically. Beam transistors in models must be installed behind the transformer. When soldered at the beginning of the chain.

Application of pulse transformers

To make an amplifier with a pulse transformer, the panel is first prepared. The easiest way to pick it up is plastic. Lamps in this situation must be connected in series. The transformer must be located on the lining. In this case, the capacitor at the beginning of the circuit will require a capacitive type. Power supplies for models are selected for 30 V. All this, ultimately, ensures good signal conductivity. An integral element of the amplifier is the modulator.

It should not be installed behind a pulse transformer. In this case, the load on the capacitors will be large. To avoid failures in the circuit, a thyristor should be used to reduce the sensitivity. It must withstand negative resistance at a level of 35 ohms. Transistors in the system are installed behind the transformer. You can use code modulators directly. In stores, they are most often sold with the PP20 marking. Their distinctive feature is the presence of a broadband head. Thus, to adjust the frequency of the device is obtained more smoothly.

headphone model

For computer headphones, capacitors can be used electrolytic type. In this case high sensitivity model is not required. Various types of thyristors are used to suppress interference in systems. It is more expedient to use modulators of a tuning type. The output voltage in the circuit must not exceed 12 V.

In order to adjust the frequency of the amplifier, compact controllers are soldered. In this case, the lamps should be installed in sequential order. The power supply is connected through a choke. Duplex resistors are rarely used in such circuits.

Guitar amp

A set for a tube amplifier should be selected only in specialized radio equipment stores. First of all, beam transistors are required. In this case, it is important to install the modulator on the panel. Capacitors are used with a small capacity. Particular attention during assembly should be given to the selection of the controller. Two-contact models are ideal for such systems. However, devices with comparators should not be considered.

Lastly, the power supply is fixed directly. The bandwidth of such systems is usually low. However, it should be borne in mind that problems with hypersensitivity are quite common. This happens in most cases due to burnt capacitors. You can solve the problem very simply by installing an auxiliary fuse.

Transistor amplifier 2SA872

A home-made lamp of this type is capable of producing an average frequency of 550 Hz. In order to assemble the model, a conventional power transformer is quite suitable. Capacitors in this case can be used orthogonal. Directly at the beginning of the circuit, resistors are used with low resistance.

Due to this, sharp jumps in the system rarely occur. The modulator must be installed behind the transformer. The lining in this situation must be used. The tube amplifier must be powered through a 20 V power supply.

A comparator is used to increase the output voltage. Most often, he is chosen network type. On average, it is able to keep negative resistance at the level of 45 ohms. After installing the comparator, you can screw the lamps. In order to avoid the feedback effect, it is more expedient to use electrolytic capacitors.

For many decades, the tube amplifier has been rightfully considered a kind of standard, if not sound, then at least exquisite design of audio equipment. I also followed the fashion. I looked at photos of various tube amplifiers - I really liked it, but why not do it yourself then? I remembered a conversation with a friend in the mid-90s, about tube amplifiers, about sound, then he said that tube sound cannot be compared with microchip and transistor sound paths. Then it was all over. But now it's time to assemble your first homemade tube ULF with your own hands. I went through a bunch of circuits and settled on a simple single-cycle circuit, where two lamps work in parallel on the load, allowing you to increase the output power by 2 times.

In the garage, a friend found an old tube TV - he was sorry to throw it away, his hand did not rise. From there, the power transformer removed the output sound, the second output was lying around with me from ancient times.

You can read a little about the power filter of the amplifier here. The output transformers were impregnated with varnish, and then I made a model of a tube amplifier - I already liked the sound.

Now it was necessary to place all this in the case. Friend has left metal case from a small system manager of an old PC, he transferred the stuffing to a standard case, and this one gave me.

It remains to place all the electronics inside - in the specified dimensions of the case. The fan did not remove, left it in place, now, during long-term operation, the lamps do not overheat in a closed case.

There is a fan switch on the rear panel.

After reading a bunch of articles about the need to ensure a gentle mode for turning on the lamps, I decided to delay the anode voltage here too.

Delay 40 seconds, just left a switch just in case, which directly supplies the anode voltage without delay.

Since I did not have the required 15 volt output to power the delay unit, and 7 volts was on the filament windings, I added a voltage doubler and everything worked out fine. Now both the fan and the LEDs are powered from the same unit.

The lamps were illuminated with a blue LED, red indicates the anode voltage delay, green - turning on the amplifier button on - net.

After the first start, the tube amplifier immediately started working on both channels, only when measuring voltages in control points it was necessary to bring the first cascade into operation.

After soldering the two resistances, everything returned to normal in terms of parameters. What are your listening experiences? The sound is cool, the background is not audible.

This is my first DIY tube amp. The view may not be great, but do not judge strictly - I collected from what was. The author of the article is Nikolay K.

Any music lover would like to hear a warm tube sound from their guitar, but not everyone can afford a good amplifier. This article will help you make your own tube guitar amplifier.

Some time ago, a friend of mine asked me to make an amplifier for him. I had some lamps and a CD-ROM drive, and I figured I could help him. In the video, my friend is playing the guitar with an assembled amplifier. Let's start assembling a simple tube amplifier!

Step 1: Tools

For assembly you will need:

• soldering iron
• drill
• glue gun
• drills for metal and wood of different sizes
• large drill 1.3 cm

Step 2: Materials

You will need a few materials for assembly:

• power transformer that can output 277-300V
• glow transformer 6V
• switch
• powerful beam tetrode 6P6S
• 12A lamp - 7 pcs.
• CD-ROM drive
• 100k potentiometer - 2 pcs.
• 6.4mm audio jack
• 0.02uF capacitor - 3 pcs.
• 0.002uF capacitor
• 120uF electrolytic capacitor
• 10uF electrolytic capacitor
• resistors: 10k, 32k, 100k, 1M
• bridge rectifier
• inductive choke
• output transformer 900:4

Step 3: Prepare the CD-ROM Drive

When I started building the amplifier, I was looking for something to make a metal case for it, and decided to use an old CD-ROM drive. First remove the bottom cover and take out all the plastic parts and electronics. Now press down on the hole in the top cover to remove the piece of metal that the sticker is holding.

You should end up with a round hole, perfect for a tetrode. Now, with a 1.3 cm drill, we drill holes for the preamp lamps. Then we drill holes in the front wall for the switch, potentiometers and audio jack. They can be inserted into the holes intended for them.

Step 4: Mount the lamp holder

The lamp holder connects the lamps to the amplifier. I decided to make a lamp holder out of wood, although you can just buy it. I painted the lamp contacts with a simple pencil and left prints on a chipboard sheet, these are marks for drilling holes. Then we drill these holes and glue the wires with hot glue, so that one bare end of the wire is in the hole.

Then we cut the sides of the lamp holder to the maximum to save space inside the drive housing. Since one lamp, 6Zh4P, serves as a turn-on control lamp, it does not need a wire. In the center we make a hole for the diode. The lamp holder is ready.

Step 5: Power Supply

Follow the diagram in the figure to assemble the power supply. Since there is a miniature autotransformer in the power supply, its chassis is "hot", because of this it is more dangerous than usual. For greater safety, use an isolating transformer, or a conventional power transformer. Be sure to use an induction choke and a smoothing transformer to remove interference. The power supply must provide a stable 300-350 V voltage for B + and up to 6V filament voltage.

Step 6: Wiring

When connecting the components, follow the diagram in the figure. To reduce the level of interference, it is better to use short connecting wires. The pinout of the lamps is also in the attached drawings. Here you can get creative and place the wires and components the way you like. Just make sure the wires that shouldn't touch each other don't touch.

Step 7: Testing

When the assembly is completed, the amplifier needs to be tested. Connect it to an isolating autotransformer and gradually increase the voltage to check if there is a short somewhere and if there is smoke. If everything works fine, plug in your guitar, iPod, or banjo and listen to some really loud music. Happy assembly!
Warning! When assembling an amplifier, you are dealing with potentially lethal voltage, you do so at your own risk!

In the comments, many complained about the unsafe design, with which I completely agree. This simple amplifier can be dangerous for people who are not familiar with electrical safety. There are also complaints about the poor filling of the amplifier. It doesn't have power transformer because I didn’t have it in stock, and I assembled the device from what was at hand. Same with the lamp holder. Finally, this amplifier will then be built into the cabinet.