So. As I already wrote, for about 3 months I have been trying to find the best circuit and the most interesting tube amplifier in terms of sound. The goal is to make a do-it-yourself tube amplifier with the least loss, both financially and in sound quality. I tried several lamps of different types and manufacturers; my first amplifier in the case, assembled by myself, was a 2-tube 6p6s and 6n9s. Lamp 6p6s (but it’s more correct to assemble a marshal of 18 watts on lamps like 6p14p, 6p14p-ev, 6p43p and what about the original EL84) I really liked the sound of the best option for the guitar. 6n9s is a double triode, so in order to save space, we replace it with a 6n2p of a more modern counterpart. After playing a month on a single-ended amplifier, I still realized that no. NOT LITTLE! I need something bigger and louder. I read dozens of articles from the forums, I understood on what principle they work, I first tried the circuit on 3 lamps and then still returned to the Marshall 18 Watt 4 lamp circuit.
Schematic of Marshall 18 Watt
The schemes differ only in tone blocks, I personally did both on the bottom, but I leave the choice to you.
(to view in a larger size, go to the link on the photo and select "in a different size > original")
The presented schemes are Lite versions
In general, the scheme is as old as the world, let's say the classics of musical sound. One of the most common schemes of the famous company. This amplifier even has its own website with hundreds of replica options. And so, began the process of buying and selecting parts. 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 collapse. I found a transformer on the radio market in Tsaritsino. I used Chamber of Commerce and Industry 245-127 / 220-50, the primary windings are just in the subject
half-cycles from lamps, and secondary 15-16 and 17-18, that is, 10 + 10 volts
windings.
To reduce noise immediately after the diode bridge, it is recommended to install a small choke. 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 from where we can buy, or we collect them ourselves.
Next, we make the chassis. The chassis is the basis on which the entire installation is done. You can buy that actually for about $100 but can be made from an old computer case. Exactly how I did it. The old AT case has a top cover and both walls are a single bent sheet. We measure how much we need and saw off.
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« » on Yandex.Photos
I made the power supply board on textolite.
Don't forget about currents! So that the glow of 6.3 volts would be enough for all the lamps. I had to buy a separate 4 * 6.3 transformer in order to power all 4 lamps. Also remember to shunt 6.3 volts to a common "-". Another of the recommendations on nutrition, I can only say that, if possible, try to break the glow and 300v into different toggle switches. Since the voltage is better to apply to a warm lamp.
on Yandex.Photos
At first I was too lazy and soldered virtually haphazardly. Everything is completely scary, the phonite is buzzing in short chaos. So it's better to be honest. But at this stage it is recommended to decide where you have what will be located. And for purely practical recommendations, I can advise you to place the lamps on the opposite side of the front panel. AND NOT VKOEM!!! case do not paint if you are not sure. you have to disassemble everything and repaint the chassis!
The board can be made from anything, the main thing is that everything is clean and tidy. and with the smallest distance of wires through which the signal flows. And just try to concentrate the power in one place and put all the wires in one bundle.
If we have collected everything and everything works for us, then it should turn out something like this.
(the article is not finished and will be added, painting ahead, assembling 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 end up with. To attach the chassis to the body, 2 boards were screwed to the side walls. Do-it-yourself amplifier he actually assumes that you will do everything and redo it 150 times if you don’t think everything through initially.
Now a little about the wiring. From my recommendations ... immediately after the sockets, put a resistor on a common (-) 1MΩ, mount it directly on the legs of the lamp, the wire from the sockets is strictly shielded.
The 6.3 volt glow wires should be woven into a tight pigtail (twisted pair).
We reduce 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 insulating one must be made from lako-cloth, but in the princepe you can use any cambric without any problems.
Well, as I said that you have to repaint the chassis.
In the end, I left only the master volume, I just threw out the rest of the tinsel. 
Thank you all friends 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 lighter.
Really awesome amp Marshal 18 watt Unfortunately, I did not collect the original circuit, but changed the output lamps to actual ones. Something that cardinally changes the sound all the same real Marshal 18 the amplifier is considered to be 6p14p (EL84)
I think that someday I will work on this project and assemble myself a marshal on Christmas trees :)
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, poraskinuv brains, gave an ad in the local newspaper to buy a 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.
Power on toggle switches (heat and delayed anode), power indicators on neon bulbs, lamp panels, output stage mode switches - triode-pentode, and feedback switches are mounted.
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 board is also made in a somewhat original way - in the 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.
So, I decided to try my hand at lamp technology. I found the necessary details and assembled the circuit on 6p14p and 6n23p lamps, at first just on a piece of iron. The output turned out to be 5 watts, the sound is loud and clear, nothing rings or cuts off. Satisfied with such ULF completely. It is powered by a transformer, which was taken from the Sirius radiogram. One 6 volt filament winding is involved, and 250 volts to power the anodes of the lamps. Although it has now become fashionable to install so-called "electronic transformers" in tube amplifiers, for beginner lamp builders I advise you to choose ordinary ones on iron.As a rectifier - a diode bridge, and as filters - 2 capacitors from a computer power supply, connected in series for 200 volts 470 microfarads, the result is an output of 315 volts on the capacitors. The whole thing is positively connected through a 2.7 kΩ resistor in the power gap. The anodes are powered by approximately 250 volts DC. We shunt the power filter capacitors with a 200 kOhm resistor so that there is something to discharge them after the device is turned off from the network.
The PSU is made in a separate case from the old tube TV. The tube amplifier itself is made in a case from a Soviet radio tape recorder, its case is thick and fits just right in size.
Sockets for lamps can be picked out from any lamp technology - they are all standard. We make a large hole with the help of small ones drilled in a circle. We clean the edges with a round file.
I made a speaker based on a 5-gd paper speaker, with a rated power of 5 watts, the base itself is made of board, the back is plywood, and the speaker on the front panel is mounted on two pressed cardboard sheets.
I made the legs for all the blocks by gluing pieces of double-sided tape to the case so that they would not scratch the surface of the table. See the video about assembling a simple ULF on lamps below:
A 3.5 mm metal plug is soldered to the input, of the "mother" type. The conductor that is connected to the audio input must be well shielded.
I removed the volume control, since it only gives extra 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!
Do not forget to put a 200-500 kΩ resistor on the input to the ground, and if you are making a regulator, then use a high-resistance one, I tried it at 1 mΩ and it turned out to be the best with it.
Perhaps the design will not seem very serious to someone, but please note 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
I was contacted by a man whom I once helped in the search for radio tubes. This time he needed help in repairing the amplifier, which he assembled on these lamps: a strong hum appeared in one channel, which he could not overcome in any way.
Here it is necessary to say a few words about the customer himself - this is a brutal biker-looking uncle, with a thick black beard and tattoos, and at the same time a kind-hearted person. His occupation matches his appearance - repairing motorcycles. 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 sheet, which was then further aged and covered with copper. Fortunately, photos of the workflow have been preserved, so with the permission of the author, I will share them:
All work was done by hand using a grinder, drill, files and, of course, a welding machine.
The design bizarrely combines modern elements and details from Soviet radio engineering.
I really liked the textured coating of the case, and I even seriously thought about using something similar in my own projects.
In general, the amplifier was left to me with a request to repair it as soon as possible. I connected it to the speakers and made sure that there was a strong hum in one channel. As you know, electronics is the science of contacts, so for sure either something has soldered somewhere, or, conversely, it has 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 low-frequency amplifier boards from the Ural-112 radiogram.
But since the location of the lamps and transformers did not suit him, he unsoldered them and carefully increased all the connections with wires.
Unfortunately, lamp technology does not tolerate such installation: long wires, repeatedly intertwined and crossing each other, collect all conceivable noise and interference. In addition, the author used a single-color MGTF wire, and it was almost impossible to figure out what went where. And there was no longer any point in leaving native boards: their only advantage, which is that they can be installed “as is” and save time and effort, was lost, and only shortcomings remained.
For example, obsolete selenium rectifiers and huge BC-type resistors, which were used only in the power supply circuit of the high-frequency radio unit (R5, R1 and R8), took their place 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 process.
At the same time, it is worth noting that this “not versed in electronics” person himself (albeit according to a ready-made scheme) soldered 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, huge 2-watt resistors were used at the same time (although 0.25-watt ones would be enough for the eyes) - he put them on the principle of “a lot is not a little”, so that there would definitely not be overheating. Here is such an amazing combination of ingenuity, direct hands and, moreover, a complete lack of experience, leading to slightly 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 now it was not necessary to power the lamps responsible for receiving the radio. The second transformer only interfered, and even hummed a lot, because its plates became loose from time to time, and the design did not allow them to be pulled securely.
In general, I realized that there is no smell of any 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 a hurry I completely forgot about photographing the workflow.
There is, however, a frame in which I use a battery and a microammeter to determine the direction of the windings of a power transformer.
Actually, it took a lot of work. After all, I, in fact, was forced to do double work: first, disassemble the amplifier to zero, and then reassemble it, but correctly. 95% of the radio components were replaced with modern ones in the process. Only the electrolytes in the power supply remained - their polished cases were an element of the external design. They are well preserved, so that their total capacitance was sufficient to ensure that the background of alternating current was not picked up by the ear at a distance of 20 cm from the speaker.
When working, I followed the basic rules of hanging "tube" installation - minimizing (within reasonable limits) the length of conductors, spacing signal and power lines in space, mutually perpendicular orientation of 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 that captured something very interesting:
Taking advantage of the absence of an extra power transformer, he made a new two-tier casing for the amplifier.
Severe tube amplifier tube amplifier, homemade, modding, Alcatraz, equipment repair, long post
It was no coincidence that square holes appeared in it: it was decided to stylize the body as the building of the Alcatraz prison! Well, what is Alcatraz without a lighthouse?
As a result, it turned out like this:
The beacon is made removable and mounted on a magnet. And the light in it is not just on, but shows whether the built-in Bluetooth module is turned on, which is one of the possible signal sources for the amplifier.
This is how the ability to work with metal and the rich imagination of the author, combined with my modest knowledge of lamp technology, led to the birth of a very unusual and functional device. I think the appropriate name for it would be "The Rock".
I haven't written anything here for a long time... Somehow everything didn't fit.
But finally, something was found that could really be interesting to someone else, besides the author.
Frankly, I thought about this topic for a long time ... I rummaged through everything that could be found on the Internet and only realizing that there was very little really sane and useful on the topic voiced in the title, I decided to crown my efforts with an epistolary report, for which, first all armed 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 for more than 30 years of practice of my radio engineering "creativity", I have never had a chance to make a completely tube amplifier.
There were many reasons for this!
I will not list them all. Let me just say that I have dealt with lamps, and quite successfully and productively. But this was due to the pre-amplification cascades and made it possible not to get involved with hemorrhoids, due to the need to mount a bunch of pieces of iron, in the form of chokes, large trances and others like them.
But here I wanted, at least once in my life, to make a classic (moreover, it’s a classic !!!) lampovik, with lamps beautifully glowing in the dark, mounted outside ...
It’s not that I didn’t understand what it would result in 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 attributed not so much to electronics as to locksmith work.
But I'm getting ahead of myself...
To begin with, as I said above, without further ado, I dug in the search engine line: "do-it-yourself tube amplifier."
However, having reached (no lie!!!) 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 in 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 is, it is very fragmented and stingy with details.
Actually, at that moment I realized that they favorably left me a place in this clearing. J
So, why, in fact, a lampovik?
I will not rant on the topic of fashion trends, such as Hi-End. It is clear that this is both fashionable and prestigious, and the tube sound, indeed, compares favorably with the transistor one. What? ... - This question is not here! If you just want to "decide for yourself" - raise the brain of your friends who have such devices, or managers in salons, such as the Purple Legion.
And if you decide that you want this, but you are not ready to spend on this “miracle” of 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. First, the stuffing was assembled there, and only then did we think about cases for our creations.
In the case of tube amplifiers, everything is exactly the opposite, since for these machines the amplifier housing 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 experience) that this is the most difficult issue in our "fatherland". Alas, in Russia, finding a decent case for radio equipment is an almost impossible task. L
I'm not that lucky ... But at one time I brought a lot of such iron from the "under heaven". Therefore, I was lucky to get past this problem. And I'll even say more! Perhaps I can help some of you deal with this problem! ;) Well, yes, it's all only privately...
In the meantime, having decided on how our creation should look, it is worth solving the second, of the most important tasks - deciding which one to assemble from amplifiers?
Schemes, ideas, not to mention opinions, just an incredible amount!
And it’s incredibly difficult to figure out on the go which of the ideas to grab on to.
In such cases, it is worth starting with the simplest and, at the same time, material that has been worked out not even for years - but for decades ...
But there is a lot of such, as the practice of studying the issue has shown.
And here, perhaps, it is worth starting to share your own experience.
There are a lot of established stereotypes in our minds. So, for example, high-speed car driving inevitably evokes associations with Michael Schumacher, and the racing car itself inevitably evokes the red Ferrari ...
Similarly, 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, the Audionot sound has been almost like a religion among a large part of the “sophisticated high-end players”
At one time, many copies were broken in the field of discussions about what, in fact, is this secret of the sound of the creations of Peter Quartrup (dad and one of the main designers of Audio Note).
I remember that this chest was opened as easily as most of the others.
A relatively small number of experiments made it possible to find out that the first cascade, usually built according to the so-called SRPP (cascade) scheme, made the bulk of the colors in the Audinot sound.
I didn’t philosophize either, having determined that it was he who should be at the entrance and nothing else, although something else could be simpler, but not much.
It's even easier with the output stage!
Here it is necessary to proceed from the principle of accessibility. Speaking of accessibility, I mean, first of all, the element base, on the basis of which you can build something quite worthy of sounding.
In this it is worth relying on the "experience of ancestors" that has come down to us in abundance in the form of the remains of old tube TVs and radiograms (Hello garbage dump!!!).
In extreme cases, this junk, in the form of weekend (TVZ-Sh) and power (TS-180) transformers, is usually in abundance at local flea markets, which take place on weekends in all regions and villages 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, designed specifically to amplify sound. Of course, we are talking about the legendary 6P14P or its more modern counterparts 6P15P or 6P18P.
However, your choice! You can also supply a “branded” analogue in the form of EL 84. How much the result will be worth it is up to you to judge. 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 are talking about lamps, it is perhaps worth mentioning the light bulb for the first stage.
I'm not afraid of shields of malicious replicas of "dissenters", but IMHO there is simply no better candidate for the first cascade than 6N23P-EV. However, I will immediately warn you that the number of people who agree with me will be approximately equal to the number of those who objected. Let me just say that if we are striving specifically for the Audionot sound, then this is the very thing! J
Well, in fact, we have almost drawn our own scheme.
To all of the above, it is worth adding, except that speaking about the output stage, I meant precisely and exclusively the 6P14P triode inclusion. It is in this inclusion that this lamp is able to touch the strings of the soul in a way that not many others.
Yes! This will result in a loss in power. But, perhaps, it was worth saying this earlier ... Hi-End is not for dubbing discos. Furthermore! 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 potential.
In addition, I will reassure you that the same 1.5 - 2 watts per channel that we can get with 6P14P in a triode connection, in terms of subjective sound volume, will seem adequate to 10 watts per channel, obtained from a typical silicon-transistor VCL.
So, just trust those thousands of people who have already walked this path before you and, believe me, were completely satisfied with the result. ;)
Furthermore! 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 ... Able to touch and warm people's souls with its very warm voice. J (Evan pulled me apart!.. Once again Sorry for the pretentious syllable.)
The only question of the circuitry of our wuxia, perhaps, was the question of "proper and healthy nutrition." And this, it must be said, is a matter of paramount importance when it comes to sound! For, the sound that we hear as a result, in fact, is nothing more than the power of your amplifier modulated by the input signal.
Hence the conclusion - the power supply of the tube amplifier must also be tube! So this is a kenotron! And if you absolutely remain adherents of the classics, then the throttle ...
And if everything is simple with a kenotron (by summing the anode currents of all the lamps, we get the total consumption, based on which the desired kenotron is selected), then with a choke, a problem can really arise ...
However, I was lucky. In my bins there was 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 2 henry inductance (usually something like that...) is enough for our purposes.
How long - how short, but on the Runet spaces I managed to find two whole schemes that almost completely correspond to all the aspects voiced above. The first of them is built exactly according to the idea that was described by me above. The second one differs only in that it has a pair of output lamps in parallel at the output, but it has a beautifully painted power supply that fully meets all my requirements.
Here are the diagrams:
In fact, strange as it may seem, the essence of my article is not directly related to the amplifier circuit ... In any case, this is not the main thing for me in this case. The main thing is to tell about how to collect all this?
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 assembly of the so-called surface mounting.
Frankly, for me this has always been the most repulsive factor in the issue of assembling tube circuits. For me, who is accustomed to making a separate printed circuit board even for a stand-alone volume changer, so that everything is correct and tidy, the very thought of parts freely dangling in the amplifier case, fastened together only by soldering and, sorry, dangling on snot, was frightening ... And , when starting to build this machine, I had to overcome some internal barrier and practically invent on the go how to fix everything so that in the future I would not worry about that, and not that .... is there anything there at one fine moment ?. ..
Well, yes, everything is in order.
We take the case of our amplifier.
First, it is worth carefully diluting those commutations that we will need later. With your permission, I will omit this stage, since it is specific and does not imply many solutions.
I will just present the result as a given. In my case, it was the wiring of the input switch, ALPS for the volume control, and the actual input, output and power connectors themselves.
Characteristically, at this stage we remove the top and bottom panels of the case. The bottom panel just interferes with us, and we need the top panel as the basis of our design.
Here is what we have at this stage:
It seems that I missed one important point ... The fact is that before proceeding with the assembly of the amplifier, you must first select at least the main elements of the future machine. They are necessary in order to determine the design of your device.
This is primarily about light bulbs, sockets for them, output and power transformers and chokes. About the very elements that are attached directly to the body.
And only after fully picking up everything you need, we can arrange it the way you like, determine the places for these elements and mark out the top panel.
Here 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, having overcome 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 very carefully, thinking about how convenient the chosen location will be for subsequent internal installation and about the mutual influence of the elements on each other.
This, of course, is about the magnetic fields of transformers and their orientation.
I suppose there is no need to present a short school physics course .. Just remember this. ;)
First of all, we place the panels for our lamps and determine the size of the holes for them:
Here we are in for another ambush and a silent question in our eyes: “And how to drill such HOLES in a sheet of iron?!”… In my case, it was exactly like that. And the answer to this question in the articles of "colleagues" who joyfully reported to me about how wonderful they assembled tube amplifiers with their own hands, I could not find.
I had to go to the nearest construction market and retrain from an electronics engineer to a locksmith.
I took the data with an ordinary caliper before going to the market. It turned out that the diameter of the holes for the sockets for finger lamps is 18 mm, and the diameter of the hole for the socket for the octal lamp (kenotron) is already 28 mm!
The 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" from "Bimetal".
Here's what it looks like:
Fortunately, I easily bought both of them on the construction market at 350 wooden ones per unit of goods.
JYou need to drill holes very carefully, and always from the side of the top panel, which will later be turned inside the case. I affirm 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 ...
Drill revolutions are the most minimal. In this case, if possible, it is worth using the auxiliary handle of the drill in order to stabilize the beating of the crown as much as possible.
Naturally, the edges of the holes obtained must be processed in order to remove the burrs that will inevitably remain after drilling the holes.
It turns out something like this:
To be continued…
