Especially for the competition from Aka Kasyan and site site.
Once again I congratulate Aka Kasyan's channel on his birthday :)
In this article, I would like to talk about tube sound and my radio tube craft.
We live in the XXI century and we all know that lamps die 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 amateurs of tube sound, because as the saying goes - "It is worth hearing the tube sound once and after that you can't delay it", but only those who deeply in their youth when they first appeared are fond of this delicate work transistors remained on the side of the lamps, well, or already in our time they fell in love with the lamp 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 novice 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 were able to support me. When I shot my first video, Aka Kasyan commented on it, which I was infinitely happy about, I was also glad of Mikhail's support. And then I realized that since Aka responded positively, then I need to continue.
It was summer and I decided to tackle something more difficult for me, and it was a tube amplifier. First, I went deep into 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 tubes (two 6P14P and 6N2P).
It seemed like I decided what I would do, but ... The details were difficult to find, 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 an 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 removed 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 items, and again there was a problem. For the first channel, everything was enough, but for the second, a couple of trances were needed - TVK and TV-ZSH, where TVK played the role of a power choke, and TV-ZSh an output transformer. Well, I coped with this problem and already went to extremes by buying a transformer. In the meantime, the second month of summer is coming, yeah, that's how long I've been searching. Well, then it was necessary to deal with the amplifier case, found the PSU case from Soviet logic and decided to be creative, of course it did not work out very well, but I think it will do for the first time. This frame from the PSU served as the basis (See Fig. 1). I made the lower base from a laminate board, and the top cover from it too, for the sidewalls I also made laminate overlays, but already lighter.
Now on the assembly: I installed the power transformer at the back, blocking it with a shutter made of the iron cover of the power supply unit (a kind of screen turned out). Inside I installed a diode bridge made of her407 diodes, two anode chokes and sound transformers (See Fig. 4.1, 4.2). Next, the upper laminate board was fitted to the body and the frescoes were removed, including for the panels of the lamas with the conductors, which were installed on this board (See Fig. 2). Now I started assembling and soldering the elements, I spread the ground. Shielded Soviet wires were soldered to the input. By the way, the glow is also from Soviet wires (See the remaining photos at the bottom of the article).
I was contacted by a person whom I once helped to find radio tubes. This time, he needed help in repairing the amplifier, which he assembled on these tubes: a strong hum appeared in one channel, which he could not overcome.
Here I need to say a few words about the customer himself - this is a brutal uncle of a biker look, with a thick black beard and tattoos, while a kind-hearted man. His occupation matches his appearance - motorcycle repair. In electronics, he, in his own words, does not understand anything. Everyone would not "understand" that they can assemble their own tube amplifiers, but oh well)
I agreed to help him, and soon he brought me this miracle:
The case for the amplifier turned out to be welded from 2mm steel plate, which was then additionally aged and covered with copper. Fortunately, there are still photos of the workflow, so I will share them with permission:
All work was done by hand using a grinder, drill, files and, of course, a welding machine.
The design bizarrely combines modern elements and parts from Soviet radio engineering.
I really liked the textured finish of the case, and I even seriously thought about using something like that in my own projects.
In general, the amplifier was left to me with a request to have it repaired as soon as possible. I connected it to the speakers and made sure there was a strong hum in one channel. As you know, electronics is the science of contacts, so for sure either something somewhere has been sealed off, or, conversely, closed. This can be fixed pretty quickly, I thought naively.
When I first looked into the "basement", at first glance, everything looked good - at least for an amplifier made by an absolute beginner. The author simply took and put inside two boards of low-frequency amplifiers from the Ural-112 radio.
But since the location of the lamps and transformers did not suit him, he evaporated them and diligently increased all the wiring connections.
Unfortunately, lamp technology does not tolerate such an installation: long wires, repeatedly intertwining and crossing each other, collect all imaginable noise and interference. In addition, the author used a monochrome MGTF wire, and it was almost impossible to figure out what was going where. And there was no point in leaving the motherboards: their only advantage, which is that they can be put "as is" and save time and effort, was lost, and only shortcomings remained.
For example, obsolete selenium rectifiers and huge resistors of the BC type, which were used only in the power circuit of the high-frequency radio unit (R5, R1 and R8), were in vain in the power section. But the resistive divider R3 – R4, which was supposed to supply a small positive voltage to the midpoint of the filament winding to reduce the noise level, was lost during the transfer.
It should be noted that this "not versed in electronics" person himself (albeit according to a ready-made scheme) unsoldered the display unit on lamps of the "magic eye" type, and even with a separate amplifier on a 6N2P lamp, which made it independent of the output level volume. True, in this case, huge 2-watt resistors were used (although 0.25-watt resistors would be enough for the eyes) - he put them according to the principle "many is not enough" so that there was definitely no overheating. Here is such an amazing combination of ingenuity, straight hands and, moreover, a complete lack of experience, leading to a little curious, but still impressive results.
Acting on a whim, the author made two channels of the amplifier completely mirrored - each with its own power transformer. This also turned out to be redundant, since it was no longer necessary to power the lamps responsible for radio reception. The second transformer only interfered, and even hummed strongly, because its plates loosened from time to time, and the design did not allow them to be reliably pulled together.
In general, I realized that there is no smell of quick repairs here, and the amplifier needs to be completely redone. The situation was complicated by the fact that in just a couple of days I had to fly away on vacation. As a result, I soldered the last details at night right in front of the customer, and the next morning, having slept a little, I was already rushing to the airport) But everything turned out as it should, and the customer was pleased with the pleasant sound of the amplifier and the absence of noise. And only later I realized that in my rush I completely forgot about photographing the work process.
There is, however, a frame in which I use a battery and a microammeter to determine the direction of the power transformer windings.
In fact, I had to work hard. After all, I, in fact, had to do double work: first disassemble the amplifier to zero, and then reassemble it, but already correctly. 95% of radio components in the process were replaced with modern ones. Only electrolytes remained in the power supply - their polished cases were an element of the external design. They were well preserved, so that their total capacity was sufficient for the ac background not to be picked up by the ear at a distance of 20 cm from the speaker.
When working, I followed the basic rules of hinged "lamp" mounting - minimizing (within reasonable limits) the length of the conductors, spacing the signal and supply lines in space, mutually perpendicular orientation of the power and output transformers, shielding, avoiding ground loops, etc.
On vacation, I had already begun to slowly forget about this project, when suddenly the customer sent me photographs showing something very interesting:
Taking advantage of the lack of an extra power transformer, he made a new two-tier casing for the amplifier.
Harsh tube amplifier tube amplifier, homemade products, modding, Alcatraz, equipment repair, long-post
It was no coincidence that the square holes appeared in it: it was decided to stylize the building as the building of the Alcatraz prison! Well, what is Alcatraz without a lighthouse?
As a result, it turned out like this:
The lighthouse is removable and magnetically attached. And the light in it does not just light up, but shows whether the built-in Bluetooth module, which is one of the possible signal sources for the amplifier, is turned on.
This is how the ability to work with metal and the author's rich imagination, combined with my modest knowledge of lamp technology, led to the birth of a very unusual and functional device. I think "The Rock" would be a good name for it.
So. As I already wrote, I have been struggling for about 3 months to find the best circuit and the most interesting tube amplifier in terms of sound. The goal is to make a tube amplifier with your own hands with the least possible financial and sound quality losses. I tried several lamps of different types and manufacturers, my first amplifier was assembled by my own hands, it was a 2-tube amplifier for 6p6s and 6n9s. Lamp 6p6s (but it is more correct to assemble the 18-watt marshal on 6p14p, 6p14p-ev, 6p43p lamps, and what about the original EL84) I really liked the sound of the most optimal option for the guitar. 6n9s is a double triode, so in order to save space, we are replacing it with a 6n2p more modern brother. After playing for a month on a single-ended amplifier, I still realized that no. LITTLE! need something more and stir up louder. I read several dozen articles from the forums, I understood on what principle they work, I first tried a 3-lamp circuit and then all the same returned to a 4-lamp Marshall 18 Watt circuit.
Marshall 18 Watt circuit
The schemes differ only in timbre blocks, I personally did the same as on the lower one, but the choice is left to you.
(to view it in large size, follow the link to the photo and select "in another size\u003e original")
The presented schemes are Lite versions
In general, the scheme is as old as the world, let's say the classic of musical sound. One of the most common schemes of a famous company. This amplifier even has its own website with hundreds of replica options. And so, the process of buying and selecting parts began. At that time, I had a couple of 6p6s lamps and a couple of 6n2p lamps before the platforms were bought. Then I started looking for transformers. The output transformer can be ordered in the online store from Yerasov, or try to find something similar on the ruins. I found a transformer on the radio market in Tsaritsino. I used CCI 245-127 / 220-50, the primary windings are just in the subject for breaking into
half-periods from lamps, and secondary 15-16 and 17-18, that is, 10 + 10 volts
windings.
To reduce noise, it is recommended to install a small choke just after the diode bridge. I used D22, although it is small in current, but nothing fatal happened to it. Lamps can be ordered either in the same Erasov or in the online store http://www.istok2.com/. We either buy all related parts where we can buy, or we collect ourselves.
Next, we make the chassis. The chassis is the basis on which all installation is done. You can buy, which is actually about $ 100 but can be made from an old computer case. As I actually did. The old AT case has a top cover and both walls are a single bent sheet. We measure out how much we need and saw off.
"" On Yandex.Photos
"" On Yandex.Photos
I made the power board on a PCB.
Let's not forget about currents! So that the incandescence of 6.3 volts would be enough for all lamps. I had to buy a separate 4 * 6.3 transformer in order to power all 4 lamps. It's also memorable to shunt 6.3 volts to a common "-". From the nutritional recommendations, I can only say that, if possible, try to break the heat and 300V into different toggle switches. Since it is better to serve the naprugu on a warm lamp.
on Yandex.Photos
At first I was too lazy and practically soldered at random. Everything is completely scary, the phonit is buzzing in short chaos. So it's better immediately and conscientiously. But at this stage it is recommended to decide where you will have what will be. And purely practical recommendations, I can advise you to place the lamps on the opposite side of the front panel. AND DO NOT WHAT !!! case do not paint if you are not sure. you will have to disassemble everything and repaint the chassis!
The board can be made of anything, the main thing is that everything is clean and tidy. and with the smallest distance of the wires along which the signal flows. And just try to concentrate the power in one place and run all the wires one by one.
If we have collected everything and everything works for us, then it should look something like this.
(the article is not finished and will finish writing, ahead of painting, assembly of the head body and cabinet, fine tuning and samples!)
Again, a recommendation, before drilling holes, think carefully or try on your knee what configuration you will have in the end. To attach the chassis to the body, 2 boards were screwed to the side walls. DIY amplifier it actually assumes that you will do everything and redo everything 150 times if you don’t think it over from the beginning.
Now a little about the wiring. From my recommendations ... immediately after the jacks, put a resistor on a common (-) 1MΩ, mount it directly on the lamp legs, the wire from the jacks is strictly shielded.
The 6.3 volt filament wires should be braided into a tight pigtail (twisted pair).
We bring all common wires (ground) to one point, such an installation is called a star. We take the wire from any old choke with a cross section of 0.75, if you find it, then the insulation should be made of varnish-cloth, but in the printer you can use any cambric without problems.
Well, as I said, you will have to repaint the chassis.
As a result, I left only the master volume, all the rest of the tinsel I just threw away. 
Thank you all for your help and information. I give a few more links to articles from. At http://rumapucm.ya.ru the scheme was completely redesigned by me and from so Light was made even more light.
Actually an obsolete amplifier Marshal 18 watt I unfortunately did not collect the original circuit, but replaced the output lamps with the actual ones. That it radically changes the sound all the same with the present Marshal 18 considered an amplifier for 6p14p (EL84)
I think that when I will do this project and get myself a marshal at the Christmas trees :)
In the article, you will learn how to make do-it-yourself tube amplifiers from scrap materials. It's no secret that tube sound is the most beautiful, its fans will exist at all times, despite the fact that the market is replete with a large number of offers of small-sized equipment on transistors and microcircuits. Consider in more detail what you should consider when making a tube amplifier.
Nutrition is the main difficulty
Yes, it is with the power supply that problems can arise, since you will need two AC voltages: 6.3 V to power the filaments and from 150 V for the lamp anodes. The very first thing you need to find out for yourself is the power of the future structure. The power of the transformer for the power supply depends on this. Please note that the transformer must have three windings. Without such power, you cannot make tube
In addition to the above-mentioned secondary ones, there must also be a network (primary) one. It must contain so many turns for the transformer to work in normal mode. And even with a significant load (and power surges up to 250 V), the winding should not overheat. Of course, the dimensions of the power supply will be rather big due to the large size of the transformer.
Rectifier
You will need to make a rectifier to get a minimum of +150 Volts DC at the output. To do this, you need to use a bridge circuit for connecting diodes. D226 diodes can be used in the design of the power supply. If you need to make high reliability, then use D219 (they have a maximum operating current of 10 Amperes). If you are making tube amplifiers with your own hands, then follow the safety rules.
Diode assemblies work well in power supplies. You only need to choose those that are able to function normally at voltages up to 300 volts. Pay particular attention to filtering the DC output voltage - install 3-4 electrolytic capacitors in parallel. The capacity of each must be at least 50 μF, the supply voltage is over 300 V.
Lamp circuit
So, now closer to the scheme itself. If you are making a tube guitar amplifier with your own hands, or for playing music, you need to understand that the most important thing is safety and reliability. The most common circuits contain one or two preamplifier stages and one power amplifier stage. The preliminary ones are built on triodes. Since there are radio tubes that have two triodes in one base, you can save a little space during installation.
And now about what elements the tube amplifiers contain. You will have to assemble everything with your own hands into a single structure. For a lamp in a pre-amplifier, it is best to use 6N2P, 6N23P, 6N1P. Moreover, despite the fact that all these lamps are analogous to each other, 6N23P sounds much nicer. This lamp can be found in the PTC (TV channel switch) block of old black-and-white television sets such as "Record", "Spring-308", etc.
Final amplifier stage
As an output lamp, 6P14P, 6P3S, G-807 are usually used. And the first will be the smallest, but the last two are very impressive in size. And the G-807 has an anode in the upper part of the cylinder. Please note that in tube ULFs it is imperative to use a transformer to connect acoustics. Without such a matching transformer, you cannot make a tube amplifier with your own hands.
Perfectly work as output transformers TVK used in vertical scanning. Its primary winding is connected between the plus of the power supply and the anode of the output lamp. A capacitor is connected in parallel to the windings. And it is very important to choose the right one! First, it must be paper (such as MBM). Secondly, its capacitance must be at least 3300 pF. Do not use electrolytic or ceramic.
Adjustments and stereo sound
It will be very easy to make stereo sound. It is enough just to make two identical amplifiers. You can find a stereophonic tube amplifier in the old Soviet technique. You can repeat the design with your own hands. But you need to consider some features:
- connects directly to the amplifier input. which is used for it, you need to choose such that there are two elements on the axis in one case. In other words, when you turn the knob, the resistance of two resistors changes at once.
- Similar requirements for the frequency regulator. It is included in the anode circuit of the first triode of the preamplifier.
Amplifier housing
If you are making a tube guitar amplifier with your own hands, then it makes sense to use a metal case. He will not be afraid of blows and other minor shocks. But if you are making an amplifier for use at home, for example, to connect to a player, a computer, then it is wiser to use a wooden case. But it should be taken into account that it is advisable to fix the power transformer to the case with rubber gaskets. With their help, vibrations are reduced.
Much depends on what the tube amplifier will be. With their own hands, many craftsmen make cases from sheet aluminum. If even small vibrations are applied to the lamp, its mesh will begin to vibrate. And these vibrations will begin to intensify, and the result is a buzz in the speakers. You also need to make a common bus, which should pass near all the lamps included in the structure. All wires, through which the signal goes, must be shielded as much as possible - this will get rid of various kinds of interference.
Circuits with transistors
And one more interesting design is tube-transistor amplifiers. You can make such with your own hands literally in the evening. But lamp structures, as a rule, are made by surface mounting. It turns out to be the most convenient and simple. And in case transistors are used, you need to use printed wiring. In addition, a voltage of 9 or 12 volts is required to power the transistor stages. Moreover, transistors are used only to build a preliminary amplification stage. In other words, you only have one tube left - in the output stage (or two if it is a stereo version).
OWN HAND LAMP AMPLIFIER
I was convinced of the superiority of the tube sound over the transistor one after the very first assembled and listened to the amplifier. Despite all the new microcircuits, transistors and other "stones", vacuum is still preferable for high-quality ULF. Whatever one may say, but passing through a void, the audio signal has less distortion than passing through germanium and silicon. Moreover, the difference is especially noticeable during alternate listening to two amplifiers. In order not to buy expensive branded LUNCH, you can makedIY tube amplifier. For those who decided to make sure of this themselves, a simple classical scheme is proposedtwo-stroke a tube amplifier with a power of approximately 20 watts per channel, from the site radiostation.ru.
For trance power, we take the good old TC180-2 from the TV. Output transformers are of type TN, but TANs can also be used.Using all the resources of military production and the invaluable help of Uncle Vadim in creatingtube amplifier, I managed to make such a device:
The basistube amplifier, is a duralumin plate 200x160 mm, 4 mm thick, on which parts and lamps are attached. Then the whole structure is painted white (black boxes are tired) and racks made of polished D95 \u200b\u200bduralumin are screwed in the corners. Power transformers and output transformers are placed in tin screens to reduce background and interference.
To save space, the power choke has been eliminated, and a simple P-filter is used instead, a 300 uF capacitor - a 15 W 100 Ohm resistor - a 300 uF capacitor. Backgroundtube amplifier in speakers, not bugged even in silence.
