Especially for the competition from Aka Kasyan and the 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 crafts from radio tubes.
We live in the 21st century and we all know that tubes are becoming obsolete, and they are not used anywhere except in tube amplifiers, but only “elite” people can afford this luxury (I mean factory production). But there are such wonderful people as radio amateurs, or lovers of tube sound, because as they say, “Once you hear the tube sound once, you won’t be able to put it back,” but only those who are interested in this delicate work are deep in their youth when they first appeared. transistors remained on the tube side, or in our time they have already fallen in love with tube sound. But they still think that only people of the older generation are interested in the field of tube amplifiers, and indeed radio engineering in general. In fact, this is not at all true, and in this article I will try to dispel this judgment. And so, time to introduce myself, I am a beginner radio amateur, my name is Danil, I am 14 years old, and I am from the city of Voronezh. Usually, after I say this phrase, everyone immediately stops taking both me and my hobby seriously. But there were people who were able to support me. When I made my first video, Aka Kasyan commented on it, which I was infinitely happy about, and I was also happy about Mikhail’s support. And then I realized that since Aka responded positively, I need to continue.
It was summer and I decided to take on something more difficult for me, and it was a tube amplifier. First, I deepened my study of the theory of tube sound, read a lot, watched videos and studied. When I already had “basic knowledge” I started searching for what kind of amplifier I would assemble, it took quite a bit of time, but I decided to start with a simple single-ended amplifier with 3 tubes (two 6P14P and 6N2P).
It seemed like I had decided what I would do, but... The parts were difficult to find, and then I realized that I needed to find an old tube TV. It also took a lot of time to find him. But after several weeks of searching, I found a TV that was ideal 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 removed 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 purchased the missing elements, and again the problem arose. There was enough for the first channel, but the second needed a couple more trans units - TVK and TV-ZSh, where TVK played the role of a power choke, and TV-ZSh an output transformer. Well, I dealt with this problem and already went to extremes by buying a transformer. Meanwhile, the second month of summer is already approaching, yeah, I’ve been searching for so long. Well, then it was necessary to work on the amplifier housing, I found a power supply housing from Soviet logic and decided to get creative, of course it didn’t work out very well, but I think it will do for the first time. The basis was this frame from the power supply (See Fig. 1). The bottom base was made from laminate boards, and the top cover was also made from it; for the sides I also made overlays from laminate, but this time lighter.
Now for the assembly: I installed the power transformer at the back, blocking it with a shutter made from the iron cover of the power supply unit (it turned out to be a kind of screen). Inside I installed a diode bridge made of her407 diodes, two anode chokes and sound transformers (See Fig. 4.1, 4.2). Next, the top board of the laminate was fitted to the body and the fresco was removed, including for the panels of lamps with condensers, which were installed on this board (See Fig. 2). Now I started installing and soldering the elements, and spread the ground. I soldered shielded Soviet wires to the input. By the way, the heat is also from Soviet wires (See the remaining photos at the bottom of the article).
As a rectifier - a diode bridge, and as filters - 2 capacitors from a computer power supply, 200 volts 470 uF connected in series, the result is an output of 315 volts on the capacitors. The whole thing is connected to the plus through a 2.7 kOhm resistor in the power supply gap. The power supply to the anodes is approximately 250 volts DC. We shunt the power filter capacitors with a 200 kOhm resistor so that there is something to discharge them after disconnecting the device from the network.
The power supply is made in a separate case from the old tube TV. The tube amplifier itself is made in a casing from a Soviet radio tape recorder, its casing is thick and just the right size.
Sockets for lamps can be picked out from any lamp equipment - they are all standard. We make a large hole using small ones drilled in a circle. We clean the edges with a round file.
The speaker was made on the basis of a 5-gauge paper speaker, with a nominal power of 5 W, the base itself was made of boards, the back part was made of plywood, and the speaker itself on the front panel was mounted on two compressed sheets of cardboard.
I made the legs for all the blocks by gluing pieces of double-sided tape to the body so as not to scratch the surface of the table. See the video about assembling a simple ULF on lamps below:
A 3.5 mm metal plug, “female” type, is soldered to the input. The conductor that goes through the audio input must be well shielded.
I removed the volume control, since it only produces unnecessary noise, and in the sound source itself (in my case, a DVD player), it is much more convenient to adjust it from the remote control!
Don’t forget to put a 200-500 kOhm resistor on the ground at the input, and if you are making a regulator, then use a high-resistance one, I tried it at 1 mOhm and it turned out to be the best.
Perhaps the design will not seem particularly serious to some, but keep in mind that this is my first step in mastering tube ULFs. The next amplifiers will be more impressive. Comrade was with you. Redmoon.
Discuss the article SIMPLE TUBE AMPLIFIER
It’s been a while since I wrote anything here... Somehow everything didn’t fit in.
But finally we found something that might actually be interesting to someone other than the author.
Frankly, I thought about this topic for a long time... I scoured the internet for everything I could find about this and only after realizing that there was very little really sane and useful information on the topic voiced in the title, I decided to crown my efforts with an epistolary report, for which, first I just armed myself with a camera to capture the process in every detail, trying not to miss a single important moment.
So, I'll start, perhaps, from afar...
It so happened that in more than 30 years of practice in my radio engineering “creativity”, I have never had the opportunity to make a completely tube amplifier.
There were a lot of reasons for this!
I won't list them all. Let me just say that I have had the opportunity to deal with lamps, and quite successfully and productively. But this was associated with pre-amplification cascades and made it possible not to deal with hemorrhoids caused by the need to mount a bunch of hardware in the form of chokes, large trances and the like.
But now I wanted, at least once in my life, to make a classic (and precisely classic!!!) lamp lamp, with lamps mounted outside that glow beautifully in the dark...
It’s not that I didn’t understand what it would entail for me... But, to be honest, I didn’t realize that, unlike the design of semiconductor (“stone”) equipment, the manufacture of a tube apparatus should rather be classified not so much as electronics, but rather for plumbing work.
But I’m getting ahead of myself...
To begin with, as I said above, without further ado, I typed in the search engine line: “DIY tube amplifier.”
However, having reached (no lies!!!) the tenth page of the search engine results, I realized that the main motive of those who had already managed to tell about their experience of creating tube amplifiers with their own hands was not the desire to teach others something, but rather the desire to show off their own achievements without sharing the secret of such “success” with others.
There is very little real information on HOW to do this, and if it exists, it is very scattered and stingy with details.
Actually, at that moment I realized that they had kindly left me a place in this clearing. J
So, why, in fact, a lamp?
I won’t rant about fashion trends, such as Hi-End. It is clear that this is both fashionable and prestigious, and the sound of tubes really compares favorably with transistors. What?... - Not here with this question! If you just want to “decide for yourself”, brainstorm your friends who have such devices, or managers in salons such as the Purple Legion.
And if you decide that you want this, but are not ready to spend on this “miracle” the money that those who sell it usually ask for this kind of equipment (and who cares, for what reason you are not ready!..) , then this article will probably be useful to you...
So, where to start?
Perhaps in this case you can easily determine the sequence of actions!
In cases with “stone” devices, everything was somewhat different. The filling was collected there first, and only then did we think about the cases for our creations.
In the case of tube amplifiers, everything is exactly the opposite, since for these machines the amplifier body is, first of all, a structure that carries all the main elements. So, first of all, decide how you would like your amplifier to look as a result, that is, decide on the case!
I must say (I know from my own practice) that this is the most difficult issue in our “fatherland”. Alas, in Rus' finding a decent housing for radio equipment is an almost impossible task. L
I wasn’t exactly lucky... But at one time I brought a lot of such iron from “under heaven”. Therefore, I was lucky enough to avoid this problem. And I’ll even say more! I can probably help some of you solve this problem too! ;) Well, yes, this is all only in private...
In the meantime, having decided on how our creation should look, it’s worth solving the second, most important task - deciding which amplifiers to assemble?
There are simply an incredible variety of schemes, ideas, not to mention opinions!
And figuring out right away which idea to grab onto is incredibly difficult.
In such cases, it is worth starting with the simplest and, at the same time, material that has been worked out not even over years, but over decades...
But as the practice of studying the issue has shown, there are many such cases.
And here, perhaps, it’s worth starting to share your own experience.
There are a lot of established stereotypes in our minds. So, for example, driving a car at high speed inevitably evokes an association with Michael Schumacher, and the racing car itself inevitably evokes an association with a red Ferrari...
Likewise, in a situation when it comes to tube Hi-End, the first thing that comes to mind for people who have already come into contact, at least to a minimal extent, with this topic is, of course, Audio Note.
For more than a dozen years now, it is the Audionot sound that has been almost a religion among a considerable part of the “sophisticated high-end players”
At one time, many copies were broken in the field of discussions about what, in fact, is the secret of the sound of the creations of Peter Qvortrup (father and one of the main designers of Audio Note).
I remember that this casket was opened just as easily as most of the others.
A relatively small number of experiments made it possible to find out that the main share of colors in the Audinot sound came from the first cascade, usually built according to the so-called SRPP (cascade) scheme.
I didn’t even bother to philosophize, determining that it should be at the entrance and nothing else, although something else could be simpler, but not much.
With an output stage it's even easier!
Here we should proceed from the principle of accessibility. Speaking about accessibility, I mean, first of all, the element base, on the basis of which you can build something quite decent-sounding.
In this case, it is worth relying on the “experience of our ancestors”, which has come down to us in abundance in the form of the remains of old tube televisions and radios (Hello, garbage dump!!!).
As a last resort, this junk, in the form of weekend (TVZ-Sh) and power (TS-180) transformers, is usually found in abundance at local flea markets that take place on weekends in all regions and towns of our “immense”...
And in conclusion, the problem of choosing an output lamp comes down to the understanding that these same TVZ-Sh output transformers were designed to work with almost the only lamp developed in the socialist fatherland, created specifically for sound amplification. Of course, we are talking about the legendary 6P14P or its more modern analogues 6P15P or 6P18P.
However, it’s your choice! You can also supply a “branded” analogue in the form of EL 84. How much the result will be worth is up to you to judge for yourself. Here I will only note that these replacements should not entail any structural or schematic changes. Even the modes of these lamps are almost identical and, most likely, you will not have to adjust anything with such a replacement on an already made and working amplifier.
Since we're talking about lamps, it's probably worth mentioning the light bulb for the first stage.
I’m not afraid of the evil remarks of the “dissenters,” but IMHO there is simply no better candidate for the first stage than the 6N23P-EV. However, I will immediately warn you that the number of people who agreed with me will be approximately equal to the number of those who objected. I’ll just say that if we strive specifically for Audionote sound, then this is it! J
Well, in fact, we have almost drawn our diagram ourselves.
To all that has been said above, it is only worth adding that when speaking about the output stage, I meant specifically and exclusively the triode connection of the 6P14P. It is in this inclusion that this lamp is able to tug at the heartstrings in a way that few others can.
Yes! This will lead to a loss in power. But perhaps I should have said this earlier... Hi-End is not for scoring discos. Moreover! In Hi-End, the quality of the device is usually inversely proportional to the power (read sound volume) at which the amplifier reveals its full capabilities.
In addition, I will reassure you that the same 1.5 - 2 Watts per channel that we can get with a 6P14P in a triode connection, in terms of subjective sound volume, will seem adequate to the 10 Watts per channel obtained from a typical silicon-transistor device.
So, just trust those thousands of people who have already walked this path before you and, believe me, were completely satisfied with the result. ;)
Moreover! I also have much more “serious” devices, which, of course, are objectively better than this creation. But this simple and seemingly completely uncomplicated machine has its own soul, gentle and kind... Capable of touching and warming people’s souls with its very warm voice. J (Evan took me away!.. Sorry again for the pretentious syllable.)
The only question of the circuit design of our wuxia, perhaps, remains the question of “proper and healthy nutrition.” And this, it must be said, is a matter of paramount importance when it comes to sound! Because the sound that we hear as a result, in fact, is nothing more than the power supply of your amplifier modulated by the input signal.
Hence the conclusion - the power supply of a tube amplifier must also be tube power! Which means this is a kenotron! And if we absolutely remain committed to the classics, then the throttle...
And if everything is simple with the kenotron (by summing up the anode currents of all lamps, we get the total consumption, based on which the required kenotron is selected), then with the choke, a problem can really arise...
However, I was lucky. In my bins I found a real choke from some old tube TV. But even if not, then the simplest and most effective solution to this problem would be to buy a banal 18-watt choke for old fluorescent lamps at the nearest construction market for 120 wooden ones. Their inductance of 2 Henry (usually something like that...) is quite sufficient for our purposes.
Whether it’s long or short, but on the RuNet I managed to find two whole schemes that almost completely meet all the aspects mentioned above. The first of them is built precisely on the idea that I described above. The second differs only in that it has a pair of output lamps installed in parallel at the output, but it has a beautifully designed power supply that fully meets all my requirements.
These are the diagrams:
In essence, strange as it may seem, the essence of my article is not directly related directly to the amplifier circuit... In any case, this is not the main thing for me in this case. The main thing is to talk about how to put it all together?
It is worth noting that the classic approach to building a tube amplifier, in contrast to transistor devices usually assembled on printed circuit boards, is the so-called surface-mounted assembly.
Frankly, for me this has always been the most repulsive factor in the issue of assembling lamp circuits. For me, who was accustomed to making a separate printed circuit even for a separate volume level variable, so that everything would be correct and neat, the very thought of parts dangling loosely in the amplifier body, held together only by soldering and, excuse me, dangling on the snot, was frightening... And When starting to build this machine, I had to overcome some internal barrier and almost figure out on the fly how to secure everything so that in the future I wouldn’t have to worry about whether or not there might be something there one day? ..
Well, everything is in order.
Let's take the case of our amplifier.
First, we should carefully route those connections that we will need later. With your permission, I will omit this stage, since it is specific and does not imply many solution options.
I’ll just present the result as a given. In my case, this was the wiring of the input switch, ALPS for the volume control, and the actual input, output and power connectors themselves.
It is characteristic that at this stage we remove the upper and lower panels of the case. The lower one just gets in the way, and we will need the upper panel as the basis of our design.
Here's what we have at this stage:
It looks like I missed one important point... The fact is that before you start assembling the amplifier, you must first select at least the basic elements of the future machine. They are necessary in order to determine the design of your device.
We are talking primarily about light bulbs, sockets for them, output and power transformers and chokes. About those very elements that are attached directly to the body.
And only after we have completely selected everything we need, having arranged it the way you like, determine the places for these elements and mark the top panel.
This is how I decided to arrange the elements of my amplifier:
I admit, I had an idea to plagiarize the topology of the arrangement of elements from one of the most popular Audio Note amplifiers, but, overcoming this temptation, I decided to arrange the elements according to the classical scheme. The idea of this topology, in this case, is not fundamental. The fact itself is important, as a stage. This must be done extremely carefully, thinking about how convenient the chosen location will be for subsequent internal installation and the mutual influence of the elements on each other.
We are, of course, talking about the magnetic fields of transformers and their direction.
I believe that there is no need to present a short school course in physics... Just remember this. ;)
First of all, we place the sockets for our lamps and determine the size of the holes for them:
Here we are faced with another ambush and a silent question in our eyes: “And how can such HOLES be drilled in a sheet of iron?!”... In my case, this was exactly the case. And I could not find the answer to this question in the articles of “colleagues” who joyfully reported to me about how wonderfully they assembled tube amplifiers with their own hands.
I had to go to the nearest construction market and retrain from an electronics engineer to a mechanic.
I took the data with a regular caliper before going to the market. It turned out that the diameter of the holes for the sockets for finger-type lamps is 18 mm, and the diameter of the holes for the sockets for the octal lamp (kenotron) is already 28 mm!
A study of the issue showed that for drilling holes with a diameter of 18 mm. you can find a classic drill, but for larger holes you will have to use a “crown” made of “Bimetal”.
Here's what it looks like:
Fortunately, I easily bought both of them on the construction market at 350 wooden ones per unit.
JThe holes must be drilled extremely carefully, and always on the side of the top panel that will subsequently face the inside of the case. I say this based on my own experience. Actually, an inquisitive eye will be able to see the consequences of my flaws in the photographs with which I accompany my story...
The drill speed is the minimum. In this case, if possible, it is worth using the auxiliary handle of the drill in order to stabilize the beating of the bit as much as possible.
Naturally, the edges of the resulting holes must be processed to remove burrs that will inevitably remain after drilling the holes.
It turns out something like this:
To be continued…
As you know, in amateur radio circles, amplifier mock-ups often remain just mock-ups. It’s easy to quickly assemble a model “on plywood”, but you often don’t have time to build a beautiful building! Difficult, expensive, lazy...
With this article I want to make my contribution to the “development” of amateur designs. So, a tube headphone amplifier housing from scratch in a day or two! The basis was taken as published on the portal. It doesn't matter. This way you can assemble a housing for any design.
We take an aluminum corner as a basis (I used a corner with a section of 20x20 mm). It is better that its thickness is at least one and a half millimeters. And carefully cut the blanks for the future body.
Carefully cut the corners at 45 degrees:
We begin to slowly assemble the structure:
This is the final frame:
I note that this is still an intermediate assembly, then all screw connections will be flush.
We take a sheet of duralumin and cut out blanks for the top and bottom covers of the future case:
Important! We cut with an allowance of 1-2 mm.
We press the cut sheet to the body with clamps (sorry, I forgot to take a photo) and drill holes for fastening both in the lid/bottom and in the corners of the frame. The fact is that the holes are made first with a drill of a smaller diameter - for threads, and only then with a larger one - for screws, separately in the housing covers. If you drill separately, nothing good will come of it. The holes just won't line up!
Make it a general rule to drill all through connecting holes immediately in the “package”.
The covers should protrude slightly beyond the boundaries of the housing. Excess in place can be easily removed with a file or grinder.
This is a picture of a different building, but the gist is clear.
We cut wooden slats for the “sides” of the amplifier. Wooden trims (also known as door trims) are perfect as a material.
This is where the right tool is a big advantage. I use the following set: an accurate disc miter box and a very high-quality cross-cut saw Kataba Speed Saw 265. The cut starts very accurately, the blade does not “walk”, the angle is maintained very well during leisurely sawing.
In addition to the hacksaw and miter box, the set includes a square and a test hacksaw blade without teeth for shooting.
Made In Japan. The clever layout is clearly visible - the teeth are sharpened inward.
Although, with some experience, you can handle it with ordinary tools.
Advice! Cut the workpieces “addressed”. Those. They applied the strip to the front of the body, marked the exact cutting line, cut it and attached it. Exactly. Then they applied the strip, for example, to the left “side” of the body, marked the cutting line, cut it precisely and attached it. This is the only way to avoid or minimize the appearance of gaps between the slats.
Small gaps after assembly can be easily closed with wood putty.
The amplifier itself was assembled on a small duralumin chassis connected to the top cover with screws and 5-7 mm racks. This is done in order to hide the lamp panels. Naturally, all the holes in the chassis and top cover were drilled in advance in a “package”. I wrote about this above.
Build process:
The parts of the rectifier and anode voltage doubler are attached to the bottom cover. The lamp filaments are powered by individual windings with alternating voltage and are “rested” against the ground by a pair of 150 Ohm resistors.
Test run:
Then everything is as usual. Sanding, painting, varnishing. It is convenient to solder the casing for the transformer from PCB. In my case it is sheet metal. Open according to the development.
DIY TUBE AMPLIFIER
I was convinced of the superiority of tube sound over transistor sound after the first amplifier I assembled and listened to. Despite all the new microcircuits, transistors and other “stones”, vacuum is still preferable for high-quality ULF. Whatever one may say, an audio signal passing through emptiness has less distortion than passing through germanium and silicon. Moreover, the difference is especially noticeable when listening to two amplifiers alternately. In order not to buy expensive branded LUNCH, you can doDIY tube amplifier.For those who decide to see this for themselves, a simple classical scheme is offeredtwo-stroketube amplifier with a power of approximately 20 watts per channel,from the site radiostation.ru.
For trance power, we take the good old TS180-2 from the TV. Output transformers are TN type, 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:
basistube amplifier,is a duralumin plate 200x160 mm, 4 mm thick, on which parts and lamps are attached. Then the entire structure is painted white (tired of black boxes) and racks made of polished alloy D95 are screwed into the corners. Power and output transformers are placed in tin screens to reduce background and interference.
To save space, the power choke was eliminated, and instead a simple P-filter is used, a 300 µF capacitor - a 15 W 100 ohm resistor - a 300 µF capacitor. Backgroundtube amplifier in speakers,Can't be heard even in silence.
