DIY hi end tube pre amplifier. DIY tube sound amplifier

Simple tube amplifier audio frequencies do it yourself or feel the warmth of tube sound

I no longer remember how and when this strange idea settled in my head - to assemble a tube amplifier. Why is also not entirely clear - I’m not a music lover, I quickly got over home theaters a long time ago, and as a souvenir of that time, I still have the Wharfedale Diamond 8.4 floor-standing speakers, which in recent years have been used exclusively as a decorative flower stand. Be that as it may, the thought settled so deeply in my head that I began a leisurely study of specialized resources, reading forums, searching for tube amplifier circuits “for dummies,” etc. etc. The lack of any experience with tube technology (the most modern gadget that I remember was a b/w TV in a student dorm in the early 90s of the last century) was frightening and attractive at the same time.

The sluggish search could have continued indefinitely if one day a wonderful resource had not been discovered - http://tubelab.com/. I settled on single-ended amplifier Tube Lab Simple Single End (SSE), ideally suited to my interests, namely: a simple amplifier for beginners with a minimum of components, the absence of any adjustments, at the same time quite universal and, judging by the reviews, proven to be excellent. The board was ordered on the website (sent anywhere except Russia and Italy), payment via Paypal, a short correspondence with the developer, enough fast delivery two boards (In addition to SSE, a board was also ordered for the advanced version of Tublab SE - “for growth”, so to speak). It was decided to order components through e-bay, not quickly, but reliably and inexpensively - delivery times were compensated by convenience (receipt at the post office, leisurely search while sitting at the computer). The process took quite a while for a long time, but I was in no particular hurry (almost 2 years passed from the moment I ordered the boards to the moment of successful activation).

First components received

It makes no sense to describe the process of assembling the amplifier board, detailed instructions with pictures are on the project website. I was especially pleased with the disclaimer:

We are not responsible for injury, accidents, acts of random stupidity, burning your house down, exploding parts, and other undesired actions (all of which are possible) resulting from the use of ANY information contained herein.

Some recommendations received during the study of materials.
Never install electrolytes “all the way”; there should be a small gap between them and the board. The fact is that when soldering, the leg heats up and lengthens, and as it cools down it shortens, and, if the fit is tight, it can simply fall off the lining. Considering that in a tube amplifier the heating and cooling process occurs regularly, this point is worth paying attention to.
The chassis of the output and power transformers should be placed perpendicularly to reduce mutual influence.
The audio input connectors should be isolated from the chassis to eliminate the possibility of “ground loops” appearing in the signal lines. If the wire is shielded, then the screen should be grounded only on one side.
Order components in excess to avoid logistics delays and save on delivery.
And most importantly, be careful when purchasing components on ebay (more on this a little later).

One of the problems that we had to face was the choice of transformers (power and output) - it is quite difficult to buy a transformer with the required voltages; if the 110-volt version is usually available from American retailers, then a 220V transformer must be ordered from the manufacturer and wait 45-60 days. In addition, they are quite heavy and the cost of shipping from the USA almost doubles the cost of the order. Fortunately, a suitable version (Hammond 374BX) was found in Germany, which made it possible to significantly save on delivery and at the same time order an inductor (inductor) for use in the output filter of the power supply. The first mistake - when ordering inductance, I selected the resistance, completely forgetting about the current, as a result I received a coil with a current limit of 100ma instead of the minimum required 170ma, I had to return to a simpler and lower quality option with an RC filter and buy the corresponding wirewound resistor, and change the resistor on the reel, if the desire arises, you can at any time. It was easier with output transformers; only Transcendar had adequate delivery times; the TT-119 model met all the parameters.

Finally, the moment came when all the components were received, there was free time and nothing stood in the way of seeing how it all would work. In violation of all safety regulations, all connections were made directly on the table in front of the monitor.

An old LG-P500 was invited to play the role of the signal source, speakers from the music center were invited to play the role of speakers, it took some red electrical tape and a little courage. Sooooo - the switching on took place, nothing exploded, the lamps glowed with a beautiful orange light... and silence, or rather, if you put your ear to the speaker, you could even hear music against the background noise, but it was not at all the “warm tube” sound that I was hoping for hear.

The first thing I decided to check was the voltage at the output of the rectifier, and I was immediately unpleasantly surprised; instead of the 375V x √2-27V= 503.33V I expected (the voltage on the secondary winding multiplied by the root of 2 minus the drop across the lamp), I saw almost 550V at the rectifier output and, accordingly, 525V B+ (anode voltage). There was no desire to test electrolytes for endurance (they are designed for 500V), so I had to turn off the power. Having checked the network voltage, I was once again surprised - it turned out to be more than 240V (a further survey of neighbors confirmed that this was the case for everyone). Fortunately, the transformer can be reconnected to this voltage. When turned on for the second time, the voltages returned to normal, but the speakers were still silent; further testing revealed the absence of anode voltage on the input triode, which, in my opinion, indicated a malfunction of the only semiconductor device- adjustable current source IXIS10M45.

Having decided that the problem arose due to overvoltage and/or a Chinese ebay seller, I ordered a new pair of IXIS10M45 from England, which seemed more reliable and faster. I must say that the next switch-on ended in absolutely the same way as the first and second ones; although the new parts looked completely different, they refused to work in the same way. This is where I began to worry, since both channels behaved completely identically, and there was absolutely no voltage at the 12AT7 anodes. Since in this circuit there was nothing else except the lamp itself, the current regulator and the a priori working small things, suspicion fell on the lamp. An auction on ebay made it possible to buy an ECC81 (European analogue of the American 12AT7) quite inexpensively, and at the same time another batch of IXYS 10M45 (again a Chinese seller, he took it with a reserve just in case). The third batch of 10M45 looked (and sounded) exactly the same as the second; for the purity of the experiment, I immediately replaced the lamp and IXYS, disconnected everything unnecessary (the second stage) and for the fourth time did not find anything on the anode of the first triode.

A complete failure, my mind refused to understand how this could be. On a breadboard I assembled a simple circuit with an LED and an adjustable current source (I used an untouched one from the third batch), powered it from the laptop power supply - and IT DID NOT WORK!!!

At that moment, the thought of a universal conspiracy began to haunt me; even what was supposed to work did not work... and I again decided to order the problematic microcircuits, only through a trusted seller (Digikey). And once again, difficulties arose even where they should not have existed. The first problem that arose (at Digikey, the minimum delivery cost to my region was $75, even for a $5 order). This problem was solved with the help of an American intermediary, but the second one emerged after placing the order - a letter was sent to my email asking me to confirm that I am not a terrorist, fill out the BIS711 form (for those interested, goo.gl/VAkDYB). I ordered regular radio components to an American address, why do I need to fill out this form I still don’t understand when buying conventional radio components. Indicating your name your name and home address in all fields, namely: I am the end user, I am the official representative of the end user, I am the buyer, I am the exporter and indicated that with all this I am a private individual, sent the completed form to Digikey, and the very next day I received order confirmation and parcel tracking.

Next batch appearance was different from all previous ones, which inspired some optimism (picture below)

The test on the breadboard was encouraging; the LED happily changed its brightness depending on the resistance of the control resistor. Five minutes to replace a part on the board...

...the next turn on and MUSIC began to sound from the speakers.

As it turned out during communication on specialized forums, fake radio parts on ebay are becoming a big problem. This is what Diyaudio moderators write
— Fake parts are a real plague by now. No small chance we all get a share of those when fishing for a quick small purchase.
— I never buy semi-conductors or electrolytic capacitors on eBay for this reason.

As a result, I received work pay, regained my self-esteem, and became disillusioned with Ebay. The case was hastily made, as it was supposed to be a prototype for testing layouts, but I unexpectedly liked it.

Currently the amplifier is working in conjunction with a Raspberry Pi&Volumio (as a source), the sound is really very pleasant and really warm (+65C). The plans are to refine the case, overcome the slightly disturbing hum, build in a USB DAC (there will be a tube sound card), it is possible to add remote control. If there is interest, I will describe the process of manufacturing the case, as well as tell you about the problems identified and ways to eliminate them.

Diagram and arrangement of elements (it is difficult to find on the website, I used it to mark the holes on the case).

In this article you will learn how to make tube amplifiers with your own hands from scrap materials. It's no secret that tube sound- 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 based on transistors and microcircuits. Take a closer look at what you should consider when building a tube amplifier.

Nutrition is the main difficulty

Yes, it is with power that problems may arise, since you will need two values ​​of alternating voltage: 6.3 V to power the filaments and 150 V or more for the anodes of the lamps. The very first thing you need to find out for yourself is the power of the future design. The power of the transformer for the power supply depends on this. Please note that the transformer must have three windings. Without such power it is impossible to make tube lamps.

In addition to the above secondary ones, there must also be a network (primary) one. It must contain enough turns for the transformer to operate normally. And even with a significant load (and voltage surges in the network up to 250 V), the winding should not overheat. Of course, the dimensions of the power supply will be rather large due to the large size of the transformer.

Rectifier

You will need to make a rectifier to get a minimum of +150 Volts DC 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 (their maximum operating current is 10 Amperes). If you make tube amplifiers with your own hands, then follow the safety rules.

Diode assemblies work well in power supplies. You just need to choose those that are able to function normally at voltages up to 300 Volts. Pay special attention to filtering the output DC voltage - install 3-4 electrolytic capacitors connected in parallel. The capacity of each must be at least 50 μF, the supply voltage must be 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 final amplifier. 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 tube amplifiers contain. You will have to assemble everything into a single structure with your own hands. For the tube in the preamplifier, it is best to use 6N2P, 6N23P, 6N1P. Moreover, despite the fact that all these lamps are analogues of each other, 6N23P sounds much more pleasant. This lamp can be found in the PTC block (switch television channels) old black and white TVs such as “Record”, “Spring-308”, etc.

Final amplifier stage

6P14P, 6P3S, G-807 are usually used as output lamps. Moreover, the first one will be the smallest, but the last two will be very impressive in size. And the G-807 has an anode at the top of the cylinder. Please note that in tube ULFs you must use a transformer to connect acoustics. Without such a matching transformer, you cannot make a tube amplifier with your own hands.

TVK transformers used in vertical scanning work great as output transformers. 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. Moreover, it is very important to choose the right one! Firstly, it must be paper (like MBM). Secondly, its capacitance must be at least 3300 pF. Do not use electrolytic or ceramic ones.

Adjustments and stereo sound

Making stereo sound will be very simple. It is enough just to make two identical amplifiers. You can find a stereo tube amplifier in old Soviet technology. You can repeat the design with your own hands. But you need to take into account some features:

1. connects directly to the amplifier input. which is used for it, you need to choose one so that there are two elements on the axis in one housing. In other words, so that when you rotate the knob, the resistance of two resistors changes at once.
2. Similar requirements apply to the frequency controller. It is connected to 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 using a metal body makes sense. 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 or computer, then it makes more sense to use a wooden case. But you need to take into account that it is advisable to attach the power transformer to the case using rubber gaskets. With their help, vibrations are reduced.

Much depends on what type of tube amplifier housing it will be. Many craftsmen make cases from sheet aluminum with their own hands. If the lamp is exposed to even small vibrations, its grid will begin to vibrate. And these vibrations will begin to intensify, and the result is a buzzing sound 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 travels must be shielded as much as possible - this will allow you to get rid of various types of interference.

Circuits with transistors

And another interesting design is tube-transistor amplifiers. You can make these with your own hands literally in an evening. But lamp structures, as a rule, are made by hanging installation. It turns out to be the most convenient and simple. And if transistors are used, printed wiring must be used. In addition, a voltage of 9 or 12 Volts will be required to power the transistor stages. Moreover, transistors are used only to build a preliminary amplification stage. In other words, you will have only one tube left - in the output stage (or two, if we are talking about the stereo version).

So. As I already wrote, I have been struggling for about 3 months to find the best circuit and the most interesting sounding tube amplifier. The goal is to make a tube amplifier with your own hands with the least loss, both financial and in sound quality. I tried several lamps different types and manufacturers, my first amplifier, actually assembled with my own hands, was a 2-tube 6p6s and 6n9s. 6p6s lamp (but it would be more correct to assemble an 18-watt marshal on lamps such as 6p14p, 6p14p-ev, 6p43p, and what about the original EL84) I really liked the sound best option for 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 it was not. NOT ENOUGH! You need to stir up something more and louder. I read several dozen articles from forums, I understood the principle by which they work. I first tried a circuit with 3 lamps and then finally returned to a 4-lamp Marshall 18 Watt circuit.

Marshall 18 Watt Circuit

The circuits differ only in tone blocks, I personally did the same as on the bottom one, but I leave the choice up to you.

(to view in large size follow the link to the photo and select "in a different size > original")

The presented diagrams are Lite versions

In general, the scheme is as old as time, let's say a classic 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, the process of purchasing and selecting parts began. At that time I had a couple of 6p6s lamps and a couple of 6n2p lamps before I bought the pads. Then I started looking for transformers. You can order the output transformer in the online store from Erasov, or try to find something similar on the breakers. I found a transformer on the radio market in Tsaritsino. I used TPP 245-127/220-50, the primary windings were just right for splitting into
half-cycles from the lamps, and the secondary ones are 15-16 and 17-18, that is, 10+10 volt
windings

To reduce noise, it is recommended to install a small choke immediately after the diode bridge. I used D22, although it has a small current, 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 the related parts where we can buy them, or we assemble them ourselves.

Next we make the chassis. The chassis is the basis on which all installation is done. You can buy it, which actually costs about $100, but can be made from an old computer case. Which is exactly what I 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.

Don't forget about currents! So 6.3 volts would be enough for all the lamps. I had to buy a 4*6.3 transformer separately in order to power all 4 lamps. Also, don’t forget to shunt 6.3 volts to common “-”. Another recommendation for power supply I can only say is that, if possible, try to split the heat and 300V into different toggle switches. Since it is better to supply voltage to a warm lamp.

on Yandex.Photos

At first I was lazy and soldered it basically haphazardly. Everything is completely scary, the fog is buzzing, in short, chaos. So it’s better to do it right away and honestly. But at this stage it is recommended to decide where you will have what. And clean practical recommendations I can advise placing the lamps on the opposite side from the front panel. AND DON'T AT ANY TIME!!! case, do not paint if you are not sure. I'll have to disassemble everything and repaint the chassis!

The board can be made from anything, the main thing is that everything is clean and neat. and with the shortest distance of wires through which the signal flows. And just try to concentrate the power in one place and run all the wires along one bundle.

If we have collected everything and everything works for us, then it should look something like this.

(the article is not finished and will be added to, painting is ahead, assembling the head housing and cabinet, fine tuning and samples!)

Again, a recommendation: before drilling holes, think carefully or try on your knees what configuration you will end up with. To attach the chassis to the body, 2 boards were screwed to the side walls. DIY amplifier he actually assumes that you will do and redo everything 150 times if you don’t think everything through from the beginning.

Now a little about routing the wires. From my recommendations... immediately after the sockets, place a resistor on the common (-) 1 Mohm, mount it directly on the lamp legs, the wire from the sockets is strictly shielded.

The 6.3 volt filament wires must be woven into a tight braid (twisted pair).

We bring all common wires (ground) to one point, this installation is called a star. We take the wire from any old choke with a cross-section of 0.75, if you find it, the insulating wire should be made of varnish-kini, but in principle you can use any cambric without any problems.

Well, as I said, the chassis will have to be repainted.

In the end, I left only the master volume, and simply threw away all the other tinsel.

Thanks to all my 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 Light it was made even lighter.

Really awesome amplifier Marshall 18 watt Unfortunately I didn't collect original diagram and replaced the output lamps with actual ones. Of course, this radically changes the sound, it’s still real Marshal 18 the amplifier is considered to be 6p14p (EL84)

I think that someday I’ll work on this project and build myself a Christmas tree marshal :)

Any music lover would like to hear the warm tube sound from his 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 several lamps and CD-ROM drive, and I decided that I could help him. In the video, my friend plays 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 few materials for assembly:

• power transformer that can output 277-300V
• filament transformer 6V
• switch
• powerful beam tetrode 6P6S
• 12A lamp – 7 pcs.
• CD-ROM drive
• 100k potentiometer – 2 pcs.
• 6.4mm audio jack
• 0.02 µF capacitor – 3 pcs.
• 0.002 µF 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 in place.

You should now have a round hole that is perfect for the tetrode. Now use a 1.3 cm drill to drill holes for the preamplifier tubes. Then we drill holes in the front wall for the switch, potentiometers and audio connector. They can be inserted into the holes provided for them.

Step 4: Mount the lamp holder

The tube holder connects the tubes to the amplifier. I decided to make the lamp holder out of wood, although you can just buy it. I painted the lamp contacts with a simple pencil and left imprints on a sheet of chipboard, 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 off the sides of the lamp holder as much as possible to save space inside the drive housing. Since one lamp, 6Zh4P, serves as a control lamp for switching on, 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 picture to assemble the power supply. Since the power supply contains a miniature autotransformer, its chassis is “hot”, which makes it more dangerous than usual. For greater safety, use an isolation transformer, or a regular power transformer. Be sure to use an induction choke and a smoothing transformer to remove interference. The power source must provide a stable 300-350 V voltage at B+ and up to 6 V filament voltage.

Step 6: Making the Wiring

When connecting 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 use your imagination and arrange wires and components the way you like. Just make sure that those wires that should not touch each other are not touching.

Step 7: Testing

Once assembly is complete, the amplifier should be tested. Connect it to the isolating autotransformer and gradually increase the voltage to check if there is a short circuit or smoke. If everything works fine, plug in your guitar, iPod, or banjo and listen to really loud music. Happy building!
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 to people unfamiliar with electrical safety. There are also complaints about the meager filling of the amplifier. It does not have a power transformer because I did not have one, 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.

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.

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 pieces 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 just 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 in creating tube amplifiers with my own hands there was not a desire to teach others something, but rather a desire to brag about one’s 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 graciously 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 problem - deciding which amplifier 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 try to philosophize, deciding that it was he and nothing else that should be at the entrance, although something else could have been 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 “correct and healthy eating" 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 effective solution This problem would be the purchase at the nearest construction market for 120 wooden banal 18-watt choke for old lamps daylight. 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 for me in this case The main thing. The main thing is to talk about how to put it all together?

It is worth noting that the classical approach to building a tube amplifier, in contrast to transistor devices usually assembled on printed circuit boards, is the assembly of the so-called wall-mounted installation.

Frankly, for me this has always been the most repulsive factor in the issue of assembling tube circuits. For me, who was accustomed to making a separate printed circuit even for a free-standing 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:

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:

The 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: