Many people, and especially musicians, are familiar with phrases such as “warm tube sound”, “tube sound”. It is clear that tube amplifiers have this sound. Let's look at tube guitar amplifiers together. Let's look at different manufacturers and their models, and also listen to examples. Those who are not familiar with tube amplifiers will learn this topic in detail, and more experienced musicians will hopefully find interesting information for themselves.

The structure of guitar tube amplifiers

To begin with, let me remind you that a guitar amplifier consists of the following parts: a preamplifier (or preamp), a power amplifier and a cabinet (the speaker for sound reproduction and its housing). In classic guitar combo amplifiers, the preamp and the amplifier itself are assembled using tubes. The most common lamps are the 12AX7 model.

12AX7 lamp

And this is what a guitar combo amplifier looks like, assembled using tubes from the inside. Actually, four lamps can be seen with the naked eye. This example is from 1956 Fender.

For those interested in amateur radio, I will give an example of one of the circuits of a tube guitar amplifier.

Fender Guitar Amplifier Circuit

Since the first guitar amplifiers were tube amplifiers, they are considered to be the standard. Models produced in the 50s or 60s of the twentieth century are a great rarity, and are also highly valued by serious musicians and, if sold, sell for very large sums of money. In general, probably every guitarist dreams of owning a tube amp. Modern devices from famous brands also try to make them similar to the old, standard ones. They are used in lamp construction, but they are also used modern technologies. The names of such models most often contain the names of their predecessors as a tribute to memory, as well as for more successful marketing.

Legendary tube amplifiers for electric guitar

Fender was one of the first to produce guitar amplifiers. This was at the end of the 40s of the twentieth century. All amplifiers of that time were tube amplifiers. And in general, electronics were based on tubes. One of the legendary Fender amps was the Bassman model. Initially, this amplifier was created for bass guitars, but the musicians experimented with the sound and it turned out that the Fender Bassman is perfect for electric guitars.

Fender Bassman

You can also note such companies as Marshall and Vox, which began their journey in the mid-twentieth century. Their Marshall JTM45 and VOX AC30 models can rightfully be called legendary.

Marshall JTM45

1966 Marshall JTM45 amplifier

The VOX AC30 was released in 1959.

VOX AC30

1964 VOX AC30 combo amp

You can also give an example of the legendary Hiwatt DR103 amplifier, which was played by the famous David Gilmour from the band Pink Floyd.

Hiwatt DR103

So, we have heard examples of the sound of different manufacturers and models. Now we need to move on to listing the pros and cons that are common to most guitar tube amplifiers.

Pros of tube guitar amps:

• Dynamics, pronounced attack;
• Volumetricity of sound;
• Volume and sensitivity have a wide range;
• The beauty of overdriven sound.

Cons of tube guitar amps:

• Large dimensions and considerable weight;
• Fragility of lamps (it is necessary to change them quite often);
• There is a “microphone effect”;
• They achieve their immediate high-quality sound at high volume;
• Amplifiers get hot and often require additional cooling.

By the way, as I mentioned above, there are many modern tube combo amplifiers that represent an excellent combination of new technologies in electronics and the design basis of classic tube models.

Real tube sound

Hello! Today we'll talk about the most important part of guitar sound - the tubes in the power amplifier! They greatly influence how the amplifier sounds, and specifically on such sound parameters as tone, volume, power, and overdrive quality. When choosing an amplifier, it is important to understand how certain lamps differ from each other; I hope that this article will help you better understand this issue. The 4 main types of tubes used in guitar amplifier terminations are 6L6, EL34, 6V6, and EL84. There are also others, such as KT66 or KT88, but if you understand the differences between the 4 main types, you will understand better the differences between other lamps that are not so common.

End section

So, let's start with the basic concepts. A guitar amplifier consists of 3 main parts: a preamp (preamplifier section), a power amplifier (also known as the power amplifier) ​​and a power section (the transformer and everything after the power amplifier). The rectifier tube in the power section has a significant effect on the sound. It is also very important which tube is placed first in the preamplifier (in place of v1). But today we are not talking about them, but about the lamps responsible for power and volume - about the lamps in the terminal. They not only amplify the signal coming to them from the preamplifier, but also add their own characteristic overdrive and frequency coloring to the sound. In my opinion, the end tubes play the most important role in how an amp ends up sounding. It is because of the differences in the terminal lamps that such characteristic terms as American and British sound, as well as various other subspecies and varieties, appeared.

Imagine this: most hi-gain amplifiers have a gain knob that controls the overdrive on the channel. Next comes the master volume knob so that we can adjust the level that is convenient for us. Thus, it turns out that we can play with overdrive and at low volume. The overdrive that you hear in this case is the overload of the preamp tubes. As a rule, the sound itself is quite fuzzy, curly (depending on the amplifier) ​​or grainy, the return from this sound is very small, it is not dynamic. You will also notice that if you raise the volume knob, the amplifier seems to begin to come to life, and the sound becomes saturated, filled with frequencies, becoming more dynamic and interesting. It's the end lamps that work.

Take for example the Deluxe Reverb, 22W - a classic American clean sound. But by raising the volume to 5-6, the amplifier will begin to overload and this sound will be completely different from what your overdrive pedal sounds like. You will notice that it has more overtones, the sound is fuller, richer, more dynamic. The amp is more responsive to your playing and the volume knob on your guitar. These are the main characteristics of terminal lamp overload. When the tube in the amplifier begins to overload (so-called break-up occurs), it seems that a little compression is added to the sound along with the overdrive. It is important, however, not to forget that in our example, the tubes in the preamplifier are also partially responsible for the overload. It is the combination of overloading the preamp and end tubes that gives that delicious and magical result!

The power tube is one of the last links in the guitar sound chain. It is located in the amplifier directly in front of the output transformer. The different types of tubes in the power supply determine the sound character of your amplifier. Know that the overall sound is made up of parts. And each of these parts is very important. Preamp, equalizer, end, transformer, speakers - all these things ultimately give the sound for which we are willing to pay such crazy money. Power lamps alone do not solve anything. But today we will talk about them.

very widely used in American amplifiers, it has become synonymous with the Californian sound. These tubes are used by Fender, Mesa Boogie and many others. Of all four types of tubes discussed in this article, the 6L6 has the most spacious sound, it is more difficult to drive, and you need to make the amplifier louder. The power of one 6L6 lamp is up to 30 W, depending on the amplifier circuit. I've come across small 15W 6L6 amps, as well as 60W guys like the Hot Rod DeVille, so there are plenty to choose from.

In my opinion, the 6L6 tube has a very powerful, articulate bass - and that’s great. When we turn on such an amplifier louder, the tubes begin to overload and compress the sound, the low end becomes denser (depending on the circuit of the particular amplifier). The highs are best described by the word "sparkling." The 6L6 is a fairly bright tube overall that sometimes needs to be darkened a little. The bright highs and expressive lows give the impression that the mids are hollow. Prominent examples of this sound are the Fender Twin Reverb, Vibrolux and Blues Deluxe amps. It's a classic glassy Fender sound, and while it has a lot of headroom, the 6L6 sounds really cool when you drive it. The rich compression and vintage character of the mids and lows work well together, and the raised top end adds an edge and brightness to the sound.

Radio tube 6V6

6V6 tubes began to be produced shortly after the first release of 6L6 in the late 30s. This little brother is less powerful than the 6L6 and does not require a powerful and expensive transformer in order to work properly. Lamp output power 7-12 W. This is a great choice for home amps like the Fender Champ.

Despite having less power than the 6L6, the 6V6 is very similar. The bottom is large and voluminous, the tops are sparkling, but the lows of this particular lamp are more elastic and easier to control, and the highs are softer, they do not have the same sharpness and sharpness as the 6L6. I also hear clearer mids. Overall, the 6V6 is a very balanced tube. The highs are bright and the mids aren't as suppressed. The attack is softer, there is a good balance of highs, mids and lows, and a calmer tone. Despite its differences with the 6L6, the 6V6 is also considered an epithet of American sound.

Radio tube EL34

The radio tube was first produced by Mullard in 1953. It has approximately the same power as the 6L6 (11-30 W). Popular amplifier models typically use a pair or quartet (4) of EL34 tubes, giving an output of 50 or 100 watts respectively. Radio tube EL34 is responsible for that very British sound. Mainly due to the fact that Marshall especially often used it in its amplifiers.

The EL34 Mullard sounds nothing like a 6L6 or 6V6. The bottom is softer, with good presence. The sound overall is not as round and voluminous, but overall has good presence. The tops are soft, transparent, not too sparkling. The middle is why everyone loves these lamps. The mids sound rich and full, but not too much. This sound fits perfectly with guitar frequencies. The sound is very rich and there is no feeling that the middle is simply raised. Everything is very balanced and fits perfectly in the pack. The ideal lamp for lead guitarists. When the EL34 is overdriven, the sound gets compressed and really starts to scream. Amazing sustain - I think this has to do with the way the tube behaves in the midrange - very dynamic. The EL34 is a great tube if you like to play loud and is very suitable for high gain situations.

Radio tube EL84

A very popular tube, it is loved by many guitarists and guitar amp manufacturers. The maximum operating voltage for the EL84 lamp is 300 Volts, and the power is 17 W; however, many manufacturers force this lamp to operate at a voltage of 400 V. As a result, these lamps are very short-lived. But unlike the other participants in the review, these lamps are the cheapest :)

The EL84 vacuum tube is the basis of the Leeds sound. Vox is responsible for this sound. The EL84 tube has its own special timbre, elastic lows, bright highs and a very interesting midrange that begins to cut through when we overload the tip. The clean sound is bright and springy, and the overdrive sounds as if the mids are deliberately turned up, while leaving a tight low end and sparkling highs. Most EL84 amplifiers seem to be made specifically to cut through the mix like a knife. And since the fashionable trend for low-power amplifiers began. many manufacturers began to actively use EL84 in their circuits

Conclusion

So, we have covered the 4 most popular types of lamps. There are others, as well as varieties of those already mentioned above. But these 4 tubes are the basis on which the idea of ​​the sound of a tube guitar amplifier is built. Don't forget that the tubes in the end are not the whole sound. The preamp, frequency control section, transformer, speakers and all other parts are very important. Didn't you know that a red cabinet doesn't sound like a black one? Well, now you can definitely figure out what direction you want to move in to get YOUR signature sound. The article is very subjective, like any description of sound in words. Different people hear differently. Most best way- listen with your own ears. Trust only yourself!

The Novik company was founded in 1992 with the goal of producing tube guitar amplifiers. More details in the History section.

NOVIK MK60/MK120 (RedBear MK60/MK120)

Number of channels: 1+

Power Watt RMC: 60W

Weight: 18/20 kg

Dimensions mm: 700x220x230

The first model launched into mass production is NOVIK MK 60/120. For Gibson Corporation, this amplifier was produced under the RedBear brand. The back of the RedBear states that it is exclusively made by NOVIK for GIBSON. I would especially like to note that Novik not only produced, but also developed this amplifier from circuit design to technology.

More details in the NOVIK tube amplifiers section.

NOVIK MK 60/120 amplifiers are single-channel tube amplifiers, made in a separate housing (head). The models differ only in the number of output tubes (2-5881 or 4-5881) and, accordingly, the final stage.

The preliminary part (Preamp) is made using 3 6N2P-EV lamps according to the classical scheme in the spirit of the old Marshall master volume.

The chosen ideology of the preamplifier is liked by a large number of users.

However, the NOVIK MK preamplifier has its own proprietary differences. The original construction of the “presence” function - this solution was carried out at the request of the main customer - the Gibson Corporation, made it possible to significantly increase the level of output of the amplifier at low frequencies. Strictly speaking, this is not just “presence”; the entire frequency response of the preamplifier radically changes. The solution was chosen specifically for the US market

The Boost function is implemented by simultaneously turning on additional capacitors in the cathode circuit of the first lamp. To do this, there is a control button on the front panel and it is possible to duplicate it via an external pedal. In this case, active switching elements such as transistors and microcircuits are not used.

Domestic dual models SP3-33 were used as potentiometers (the total power was 1 watt), which had a positive effect on the sound quality and had a very easy operation. If the American user was accustomed to this, then the European ones wanted a standard heavy move. For the European market, potentiometers with heavy strokes were installed, but less powerful.

The dynamics of the amplifier were positively influenced by the power unit, made with a very large reserve (later similar power transformers were successfully installed in NOVIK 2X120 watt power amplifiers).

Novik was one of the first (if not the first in the world) to use an open (transparent) amplifier design with grilles instead of a blank front and rear panel.

In addition to the high-quality sound, the MK amplifiers received such a manufacturing quality (implying an almost unlimited service life), which made it possible and still makes it possible to compete with the best examples of world guitar amplifier construction.

This is confirmed by constant tests in the USA, where the majority of MK, MKE and MKX amplifiers continue to operate.

NOVIK MKE60/MKE120 (RedBear MKE60/MKE120)

Final stage lamps: 2x5881 (6P3SE option)

Pre-stage lamps: 12AX7 (6N2P option)

Number of channels: 1+

Power Watt RMC: 60W

Weight: 18/20 kg

Dimensions mm: 700x220x230

The MKE60\120 model is practically the same MK amplifier with the addition of 4 tubes in the preamp, providing loop operation with adjustable input and output send and return.

Red Bear MKX 50

Final stage lamps: 2x5881 (6P3SE option)

Pre-stage lamps: 12AX7 (6N2P option)

Number of channels: 1+

Power Watt RMC: 50W

Dimensions mm: 470x540x230

Speaker: Celestion Vintage 30

The first serial combo amplifier from NOVIK is the REDBEAR MKX50 CAB COMBO.

The exterior design is quite unusual and was entirely developed by Gibson.

The amplifier used in the combo is very similar to the MKE60. The difference is that the anode voltage was slightly reduced (430V instead of 470V) and the output power was correspondingly reduced (50 watts instead of 60 watts). However, at the request of Gibson engineers, it implements a circuit design that has not previously been seen anywhere in other amplifiers. A standard paraphase inverting stage is not directly grounded.

This decision made it possible to combine the sound of the combo as much as possible with the sound of Gibson guitars (although instrument tests of the amplifier turned out to be very controversial). Novik later refined this model, resulting in the NOVIK MKX50+ model.

Setting the final stage mode switch allowed us to get 2 different sounds:

1 - original sound REDBEAR CAB COMBO.

2 - classic NOVIK sound.

If the REDBEAR MKX 50 CAB COMBO was manufactured by NOVIK exclusively for Gibson, and was sold mainly in the USA, then the NOVIK MKX 50+ was subsequently sold in Europe and Russia.

NOVIK N602/N1202

Final stage lamps: 2x5881 / 4x5881 (6P3SE option)

Pre-stage lamps: 12AX7 (6N2P option)

Number of channels: 2+

Power W RMC: 60W/100W

Weight: 18/20 kg

Dimensions mm: 700x220x230

NOVIK 1202/602 is the first serial amplifier that NOVIK began selling under its own brand. The main distributor was the large German company PELLERIN.

NOVIK 1202/602 received a classic power amplifier (similar to MKE120/60) and a 3-channel preamp (2+), in the development of which German engineers took part.

The preamp is assembled using 5 12AX7 tubes. To switch channels, very high-quality relays were used (no transistor switches or microcircuits). A switchable series-parallel loop with smooth adjustment of input and output is also used.

Amplifier received good reviews in leading German music magazines.

Final stage lamps: 2x5881/4x5881 (6P3SE option)

Pre-stage lamps: 12AX7 (6N2P option)

Number of channels: 2+

Power W RMC: 60W/120W

Dimensions mm: 500x700x230

Speaker: Celestion Vintage 30

As a continuation, a combo version of NOVIK N1202C/N602C was developed.

The N1202C was equipped with 2x12" CELESTION VINTAGE 30 speakers.

The N602C was equipped with 2x12" CELESTION G12L-35 speakers.

NOVIK MK25K/MK50K

Final stage lamps: 2x5881 (6P3SE option)

Pre-stage lamps: 12AX7 (6N2P option)

Number of channels: 1+

Power Watt RMC: 50W

Dimensions mm: 470x540x230

Speaker: Celestion Vintage 30

B1996 NOVIK releases a new combo amplifier. This is NOVIK MK50K/MK25K intended for sales in Russia.

All design ( appearance, chassis design, circuit design, etc.) was developed exclusively by NOVIK.

The following task was realized - to make a powerful, but very light and compact combo, at a reasonable price.

The amplifier consisted of a power block assembled on 2x 5881 (MK50K-50watt) and 2x6V6 (MK25K-25watt), and a single-channel 1++ preamp assembled on 4x 6N2P-EV.

Means 2 function switches

1. Switchable boost (as in MK and MKE)

2. Branded (Novikovsky) switch for final stage and presence modes at the same time.

The MK25K was equipped with a G12L-35 (weight 11 kg).

The MK50K was equipped with G12T-75 or VINT 30 (weight 13 kg).

The result was a very successful amplifier in terms of sound and tuning, but very inconvenient to service, which largely predetermined the future fate of this model.

Final stage lamps: EL84/6V6 (6P14/6P1/6P6) (switchable)

Pre-stage lamps: 12AX7 (6N2P option)

Number of channels: 1

Power W: RMC 7(5) W

Weight: 8 (10)Kg

Dimensions mm: 330x310x180 (460x460x210)

Speaker: Celestion Super8 (Celestion Vintage 30)

NOVIK MK 6

Final stage lamps: 2x5881 (4x5881) (6P3SE option)

Pre-stage lamps: 12AX7 (6N2P option)

Number of channels: 1+

Power W RMC: 60 (120) W

Weight: 18/20 kg

Dimensions mm: 700x220x230

New amplifier Novik MK 6 - two options for overdriven sound, 4 12x7 tubes and 4 EL 34 tubes. Novik MK 6 is a working machine for the guitarist. Works great with any gadgets. The sound is clear, focused, with a powerful attack and a huge amount of nuance, responding perfectly to sound production. Thanks to the use of EL 34, the low end became denser and clearer. Very popular with those who like to play with their fingers, but with serious overload. As the gain is increased, the sound does not become blurry and intelligibility remains excellent. It responds superbly to operation of the volume knob on the guitar, and the sound ranges from pure to furious drive.

NOVIK MK 12

Final stage lamps: 2xEL 34 (4xEL 34)

Pre-stage lamps: 12AX7 (6N2P option)

Number of channels: 1+

Power W RMC: 60 (120) W

Weight: 18/20 kg

Dimensions mm: 700x220x230

Novik MK 12 - complete with 4 12AX7 lamps and 4 5881 (6L6) lamps. In essence, this is an updated RedBear, differs from its older brother in a more “combed” sound, but does not lose either character or aggressiveness, but conveys more nuances of the game due to greater dynamics. There was more “body” in the sound, it became “fatter”, more viscous, but at the same time more structured. The attack has become much brighter, but not due to the top, as usually happens, but due to the fact that the dynamics of the amplifier have risen, and the sound hits the entire spectrum, and not just the top. Especially for lovers of riffs, there is a magic button, when pressed, the operation of the output stage driver and the feedback circuit are radically restructured, which has the most positive effect not only on attack and dynamics, but also on sound damping.

NOVIK Bass Tube

Final stage lamps: 4xKT88

Pre-stage lamps: 12AX7 (6N2P option)

Number of channels: 1+

Power Watt RMC:120W

Weight: 18/20 kg

Dimensions mm: 700x220x230

The amplifier is called Bass Amplifier, which, however, does not indicate its purpose only for bass, but emphasizes its ideological kinship with the Bassman amplifier. Equipped with 4 12x7 lamps and 4 KT88 lamps. . This is an amplifier that fulfills the dream of many guitarists about a transparent, powerful clean sound that is very responsive to playing dynamics, and with a harder attack breaks into a viscous, sweet overdrive. What was called “break-up” in the 60s and 70s. On this class of devices they got a sound called “woman tone”, on this class of devices they got their crazy “pure overdrive” Stevie-you-know-who. And don’t believe that such a sound can be achieved with a preamp, or that the “super-secret-custom-heater-808” system will save you. Lamps are important here. Moreover, weekends, with a large current and a large current reserve. We have just such ones - KT-88. The amplifier has two inputs, each with its own gain potentiometer. One entrance is more “American”, the other is more “British”. But this amplifier has something in common with the “Red Bear”, either the ability to “roar”, or the power and breadth of sound. Although, maybe it's just a bear?

NOVIK 02

Power Max: 2x50W, 2x25W

RMS Power: 2x20W, 2x10W

Type and number of output tubes per channel: 2x6V6+26Q5B

Operating mode: class A

Dimensions mm: 500x230x170

Guitar two-channel power amplifier (class A) Novik 02 Black Fire, (2xEL84 +2x 6V6) independently switchable in each channel. Included in the Send of a 100 watt head, it uses its preamp, and its two channels are included on the speaker and it is not stereo. This inclusion allows not only to solve the main problem of a powerful stack - too much volume. The required quality and drive are obtained, as a rule, at very high power - and this is not possible or appropriate everywhere. Novik N02 allows you to achieve dynamics comparable to a 100-watt amplifier at much lower volume levels. But that's not all - at much lower levels you can not only get the necessary drive, but also gain a large number of different sound options. And this is all on your usual preamp. Generally speaking, the Novik N02 amplifier requires some reconsideration of views on the formation of guitar sound. You have two channels at your disposal, each with its own volume control, presence control and switching of the output pair (or quadruple) of lamps. What to do with all this? Include a mono signal on two channels. This is where the fun begins. As an example, consider this option:

Using an external preamplifier (mono), in the first channel of the Novik N02, we select an EL 84 tube, a crisp top appears, the sound is transparent, but not dense. I want density. In the second channel we select 6V6, density appears, low end appears. By tidying up the presence, we aggravate this character of the sound. Then we set the balance of two characteristic sounds, and as a result we get a sound that is unattainable on conventional amplifiers without significant resoldering and reconfiguration. Moreover, there are a huge number of sound options, setup is fast and intuitive.

At the same time, you get a unique opportunity to move away from the small multi-colored boxes that we all love so much, and use the ability to combine different final amplifiers in different proportions to find your sound. It is easy to combine dynamics, the ability to load the final stage and saturate the transformer of each amplifier channel. This terminal is ideal for work in the studio and in clubs, especially in those where they are sensitive to sound. But it won’t look pale on the big stage either; after all, the maximum 50 watts is serious.

How many people have so many opinions, and tube sound is no exception. Many music connoisseurs are inclined to believe that tube equipment reproduces sound better than its semiconductor counterparts. This article is not intended to bring any clarity to such judgments; for my part, I will try to refrain from “labels” and assessments.

An important “consumer” of tube amplification devices are musicians, mostly guitarists. It’s difficult to say for sure what the basis for such popular love is, but on my own behalf I can only add that all the guitar amplifiers I assembled were tube ones, and the sound of not a single one of them disappointed me. Today I would like to talk about perhaps the simplest design of a tube guitar amplifier that you can find. This design does not burst with enchanting innovations in the scheme; everything is assembled, as they say, “according to the textbook,” let’s take a look:

The classic triode-pentode combination, recommended lamp modes and minimal body kit are the characteristic features of this unit. While simple, the amplifier delivers 3 watts of undistorted power from 100 Hz to 12 kHz and an input sensitivity of 130 mV. If you do not set yourself the goal of scoring a concert hall, but just want to rehearse with friends at home, this option may be the most optimal solution. The circuit is simple, does not contain scarce parts, requires virtually no configuration and works stably. If you have experience in assembling radio equipment, assembling such an amplifier will not take much time.

Moving from left to right, let's take a closer look at the diagram. The first element in it is resistor R4 - it is necessary to create a bias on the triode grid. Its practical role is to set the sensitivity level of the amplifier input. The higher its rating, the higher the sensitivity will be. On the contrary, by reducing it, the amplifier input becomes less sensitive. It is worth decreasing and increasing it at the stage of setting up the amplifier. The maximum value of this resistor is usually indicated in the lamp specifications. For the 6N1P lamp, which is used in our case, this value is 1 M (megaohm). The next element is the triode lamp itself, on which the preliminary stage is assembled. Instead of the indicated lamp, you can use triodes similar to it: 6N3P, 6N2P, 6N23P. The body of the preliminary stage consists of resistors R2, R3 and capacitor C2. Resistor R3 is located at the cathode of the lamp, which sets its operating mode. Its value is selected depending on the desired voltage readings at the anode and based on the characteristics of the lamp. The power of the resistor can be small; in our case, half a watt will be enough. This resistor is bypassed by capacitor C2. The maximum capacity of this capacitor is desirable - this will overcome some of the background, the lamp will work more stable, and this, in turn, affects the final result - the sound. Since the voltage in the cathode circuits is usually small, the operating voltage of the capacitor may not exceed 10 Volts. In the above circuit, the voltage at the cathode is no more than 1.3 - 2 Volts. Last, but not least, the element of the preliminary stage is the resistor in the anode circuit. Its value is determined in the same way as resistor R3. The power may not exceed 0.5 - 1 Watt. The normal voltage reading at the anode of the lamp of this circuit will be 90 - 100 Volts.

The preliminary stage is necessary in order to “swing” the final stage, the sensitivity of which is very low. The connecting link Between these two stages there is a transition capacitor C1 and a variable resistor R1. The operating voltage of the capacitor must be at least 300 Volts, this depends on what voltage will be at the anode of the triode. As for the rating of this capacitor, not everything is as simple as, for example, in the cathode circuits. Through this capacitor, the sound actually passes into the next amplification stage, which means that the quality of the capacitor directly affects the sound quality. It is important to remember that the larger its capacity, the better it will pass low frequencies, and vice versa, the smaller the capacity, the better it will pass high frequencies. The transition capacitor affects the entire sound color and timbre of the entire amplifier, and you can find your sound experimentally: try capacitors of different capacities and settle on the option you like best. Resistor R1 is used to adjust the volume. Its denomination can range from 100k to 1M. The characteristic is desirable to be logarithmic or straight. The biggest problem will be the cracking noise. About 90% of all variable resistors crackle during their rotation and thereby significantly spoil the overall picture. Using the same experimental method, it was found that the highest quality in this regard are variable resistors from ALPHA; if possible, try to find them.

The final stage is implemented on a 6P14P lamp. Its connection circuit is also typical and is based on the characteristics of this pentode. The only component of this lamp is the cathode circuit. As in a triode, there is a resistor R5, which is bypassed by an electrolytic capacitor C3. The resistor power in this case is needed more than in a triode, and in my version it is 2 Watts. The rating is not far from the recommended 120 Ohms. The capacitor in this circuit may have a smaller capacity compared to the triode.

One of the main elements of any tube amplifier is the output transformer. In this circuit, the Soviet output audio transformer TVZ-1-1 was used. It is designed for a load of 8 Ohms and is quite acceptable for a power of 3-4 Watts. You can also use TVZ-1-9 transformers (for a 4 Ohm load). As an experiment or if it is not possible to obtain an audio transformer, you can try to use TVK type transformers for these purposes, but you should remember that the frequency response and level of distortion in this case may be significantly inferior to specialized transformers.

Setup and Debugging The assembled circuit consists in selecting the ratings of the parts that set the modes for the lamps. This also includes the selection of a transition capacitor. When turned on and after the tubes have completely warmed up, the amplifier works immediately. It is better to measure all voltages when the amplifier has warmed up well, 15-20 minutes after switching on and operating.

Amplifier Assembly Tips. When assembling a tube amplifier, even one as simple as this one, it is worth remembering that one of their main problems is the background. Background can occur for many reasons. In order not to sit for hours and not look for where all sorts of nasty stuff gets into the useful signal, you can use such a technique as assembly from the end. The point is that the amplifier is assembled not from the beginning (pre-stage) but from the end (final). That is, the first thing we do is assemble the pentode part: connect the output transformer, power the cathode circuit and turn it on. If a slight background noise/crackling noise is heard in the speakers/speakers, the cascade is working. When you touch the output of the first grid with your finger or a screwdriver, there should be a characteristic sound. If the reaction does not occur, something is wrong, you should check the installation and wiring of the elements, the functionality of the lamp or output transformer with a speaker, measure the voltages and check the modes. When the final stage is assembled, you can move on and assemble the preliminary stage. The technique is still the same: collect, turn on and listen. This assembly sequence allows us to determine in which of the cascades the background appears, which means that we know where to fight it. It is important to remember safety precautions - be careful when working with high voltage.

Such an amplifier can be implemented on various types of chassis - in this regard, your imagination is your best assistant. It is important to remember that before drilling holes, you should carefully consider the layout of all elements outside and inside the chassis. My version of the amplifier is implemented on a piece of galvanized aluminum profile measuring 250mm (length) by 75mm (width) by 40mm (height). This chassis material was chosen because it conducts well electric current and grounding can be done directly through the chassis and is also easy to solder to. It looks like this:

The power supply is shifted to the left. It consists of a TAN-19 power transformer and a choke, then there is an output stage lamp, a preliminary lamp and an output transformer. It is advisable to place the preliminary stage lamp further from the power transformer, since it is more sensitive to the background from alternating voltage. To reduce the background, you can also place it on the screen. The power and output transformers should also be spaced further apart.

It is better to twist all the wires carrying alternating current together in a pigtail of 2 - this reduces the background and prevents the wires from dangling. The wires should be as short as possible, but not so short that they interfere with installation and configuration.

One of the disadvantages of such a chassis is that it is quite flimsy due to its thinness. Also significantly spoiling the overall picture is the fact that it is necessary to cover the sides of the chassis with something. To avoid scratching the surface on which the amplifier stands, insulating tubes were used. Inside the installation is carried out as follows:

All elements that sit on ground at one end are soldered directly to the chassis. In general, the entire design of the amplifier was developed from the point of view of the required minimum and practicality, which made it possible to assemble it in half an evening.

P.S. The design of the amplifier turned out to be so practical that it was decided to design the device in a full-fledged case. No changes were made to the design, but in its reincarnation, double-sided fiberglass was used for the chassis, and the body was made of oak steps, pre-impregnated with stain and covered with varnish.

List of radioelements

Designation	Type	Denomination	Quantity	Note	Shop	My notepad
V1	Radio tube	6N1P	1			To notepad
V2	Radio tube	6P14P	1	6N3P, 6N2P, 6N23P		To notepad
C1	Capacitor	10 nF	1			To notepad
C2		4700 µF, 10 V	1			To notepad
C3	Electrolytic capacitor	330 µF, 10 V	1			To notepad
R1	Variable resistor	500 kOhm	1			To notepad
R2	Resistor	110 kOhm	1	1 W

Despite the abundance of alternative options, the guitar amp stack remains a cult piece of equipment to this day and provides the most flexible sound control.

1. Introduction

We bring to your attention a review dedicated to choosing a guitar amplifier or, in more familiar language for guitarists, a “head”.

Despite the fact that combo amplifiers are in many ways more convenient than "head" amplifiers, despite the fact that modern digital technologies sometimes offer very attractive alternative options, the stack, that is, the combination of a separate amplifier and a speaker cabinet, remains the most common choice among professional performers. Although transistor amplifiers can be found on the guitar equipment market, tube technology has ruled the roost in this area for more than 50 years.

2. Background

Guitar amplification developed in parallel with the development of the electric guitar itself. The need for amplification arose at a time when, at the beginning of the 20th century, there was a tendency to expand dance and other groups at the expense of instrumentalists, as a result of which the overall volume increased. Although the guitar, at that time still a purely acoustic instrument, was part of the rhythm section of such ensembles on an ongoing basis, its sound was lost against the background of drums and brass. Even one saxophone or trumpet sounds significantly louder than an acoustic guitar, so it is not surprising that in a team that included five or six wind instruments, the guitar could only play rhythm parts, and even those at the limit of audibility.

From a modern point of view, it was extremely fortunate that guitar amplification began to develop even before truly high-quality amplification technologies were created. The original goal of the designers was to enhance the sound of an acoustic guitar without changing its timbre. However, fortunately for us, the radio components available in the thirties and forties simply could not cope with such a task. Early recordings of the electric guitar, when the instrument had not yet moved as far away from the acoustic guitar as the rock guitar of subsequent decades, have a characteristic "droning" sound. This sound resulted from a lot of fine distortion, compression, and a very narrow frequency bandwidth. Thus, as you can see, all the prerequisites for the emergence of the modern rock guitar sound already existed!

By the mid-60s, the electric guitar was already a widespread instrument, playing a major role in pop music on both sides of the Atlantic. However, guitar amplification technology was still very imperfect, and guitarists of popular bands of the time, in order to “break through” the crowds of hysterically screaming teenagers, were forced to turn the volume of their rather puny amplifiers to maximum...

As the load increases, any analog audio circuit will sooner or later begin to become distorted. In terms of hi-fi sound, such behavior is completely unacceptable - and the quality of amplifiers designed to reproduce music is very often characterized by how low the distortion will be at maximum volume. However, in the 60s, guitarists were forced to increase the volume of amplifiers, which were very far from hi-fi. And at one fine moment they suddenly realized that the resulting overloaded sound was, in fact, not so bad, if not vice versa.

At that time, the main element base for electronic devices were vacuum tubes, which were later replaced by transistors. Transistors were superior to tubes in every way - they were much smaller, cheaper and more reliable. Subsequently, microcircuits familiar to all of us appeared, which, in fact, are sets of thousands and even millions of microtransistors. However, guitarists discovered overdriven sound back in the tube era, and it turned out that in one parameter tubes are significantly superior to transistors - their overdriven sound is significantly more musical and more pleasant to the ear. And so it turned out that tubes are still used in guitar amplifiers. Although manufacturers would love to switch to pure transistor technology, guitarists continued to claim that transistors did not sound as good as tubes when overloaded. If today there are transistor amplifiers with good sound, it is only thanks to many years of research devoted to the question of why tubes sound more musical and how to bring the sound of a transistor amplifier closer to the sound of a tube amplifier.

Since overdrive was originally a natural “defect” in the sound of an amplifier, the distortion effect could only be achieved by turning on the amplifier at maximum volume. Until the late 60s, guitar amplifiers were equipped with only one volume knob, which “guided” the audio signal through all stages of amplification. In other words, you could either get a clear and quiet sound, or an overdriven and loud sound. With the growing popularity of overdriven sound, this became a serious problem - many performers wanted to play with distortion at relatively low volumes, for example, in clubs, at home, at rehearsals, without running the risk of deafening both themselves and those sleeping in neighboring houses. As a result, two different technical solutions were proposed: a distortion pedal and a master volume control.

The idea behind the pedal was to distort the sound before it reaches the amplifier. Because early pedals used only transistors, they could not accurately reproduce the sound of tube distortion. However, they were connected to tube amplifiers, which significantly improved the sound. Many classic recordings of the era were made with distortion pedals, which on their own (i.e. without an amp) sounded little more musical than a wasp stuck in a jam jar.

The master volume control, first proposed by l specialists, turned out to be a more useful find. The idea was that the overdrive is done in the preamp stage (that is, the timbre itself is formed in the preamp), and the master volume control controls the level of the final amplifier (which “swings” the signal before sending it to the speaker input). Today, almost all guitar amps use this type of design, and therefore always contain at least two controls - GAIN (which simultaneously controls both the depth of the distortion and the volume) and VOLUME (which is responsible only for the final volume).

3. Transistors vs tubes: how are you doing today?

Another modern trend worth mentioning is the so-called “hybrid” design options. As follows from the self-explanatory names like “Valvestate”, “Transtube”, etc., they use both tube and transistor technologies. Typically, as part of a hybrid device, a tube preamplifier is combined with a transistor final amplifier, that is, first the tube forms a unique “tube” sound, which then “swings” on the transistor “end” as neutrally as possible, with a minimum of distortion. Many hybrid amps contain only one tube, which is why some players consider them to be unworthy "breadboards", although in reality this is not entirely true.

As a rule, transistor amplifiers dominate the inexpensive price segment of the market or offer significantly more power and functionality for the same money. Although tube amplifiers are significantly more expensive, they are still considered the only choice for performers for whom sound quality is more important than the money spent on achieving it. These musicians rightly point out several significant disadvantages of hybrid designs.

The first "weak" point is that classic rock distortion is not created only at the preamp stage. The distortion of the final amplifier, as well as the distortion introduced by the speaker, are also extremely important. And this is actually true - the sound of a Marshall stack pumped up to full volume, especially if the amplifier belongs to the era before the advent of the master volume knob, is formed “on the body,” that is, the sound of the entire structure as a whole sounds.

The second point is that due to the physical design features of the lamps, they “respond” to changes in the input signal level thousands of times faster than transistors; in addition, lamp circuits are usually simpler than transistor ones, due to which the length of the signal path is significantly reduced. In normal human language, tube amplifiers are much more “responsive” than transistor ones. For the reasons described above, transistor and digital amplifier models in the top segment cannot in any way compete with tube models.

4. Tube Amplification Basics

Amplification circuits are often described in terms of the so-called “topology”, that is, the layout of the connections between radio components, which plays a very significant role in the formation of sound. Most classic guitar amplifiers are built according to the so-called "Class A" circuit, which is characterized by a wide dynamic range, punchy sound and beautiful “creamy” overdrive. Early Class A amplifiers that were not equipped with a master volume control could only produce distortion at maximum volume, so one of the main disadvantages of such a circuit is considered to be the relatively short life of the tubes due to increased wear. Such amplifiers require very frequent maintenance.

Class B amplifiers wear out less quickly and have a cleaner sound throughout the signal chain, so they are considered more versatile.

Tube amplifiers, which many consider to be some of the best available today, usually combine class A and B circuits. Often the amplifier even has a switch that allows you to select the required diagram gain.

In addition to topology, characteristics such as “British” or “American” sound are often used to describe the sound of amplifiers. The difference relates primarily to the overdriven sound, and it is almost impossible to describe it in words. The "British" sound is the classic 70s rock sound (Led Zeppelin, Deep Purple, Free, Thin Lizzy, etc.), while the "American" sound can be heard from bands like Green Day.

Modern heads and combos usually have the same set of functions. The vast majority have two separate channels with independent preamps optimized for clean and driven sound reproduction respectively. Typically, channel switching is done using a footswitch. Some manufacturers, such as Mesa-Boogie, sometimes add a third "Crunch" channel for performing overdriven rhythm parts.

Most amps are equipped with an effects loop for connecting external pedals such as chorus, delay, phaser, etc. Typically the effects loop is located between the preamp and the power amp, although some amps allow you to work with the insert point in more variety, such as assigning the effects loop only to one of the available channels. The effects loop is especially important if you prefer to use the amp's own overdrive rather than a separate distortion pedal, but still want to add modulation effects such as chorus or flanger. Such effects must be connected after the overdrive - chorus placed before the overdrive sounds simply terrible! Other effects, such as delay or wah, can be added at the discretion of the performer.

An amplifier's wattage only gives an approximate (and very rough) idea of ​​its maximum volume, since volume depends on the circuitry, impedance, and sensitivity of the speaker(s). As a rule, most “loud” amplifiers have a power of 50 - 60 watts; 100-watt heads are usually used for more comfortable “pumping” of cabinets with four or eight speakers.

One last note - the speaker cabinet is connected to the amplifier using a cable with a jack connector. Despite the fact that externally the speaker cable may look exactly the same as the signal cable, under no circumstances should you try to confuse them! The instrument (signal) cable uses coaxial wire - a central conductor with a screen braid that protects against interference. A thin wire means high resistance, and as a result, when connecting such a cable between the amplifier and the cabinet, at best the sound will be hopelessly spoiled, and at worst, the amplifier may overheat and even catch fire! The speaker cable is two-wire, it does not have a shield - if you accidentally connect a guitar with this cable, nothing bad will happen, but the sound will be simply terrible.

5. Stack or combo?

Since the 50s, there have been two types of amplification setups - a separate amplifier ("head") plus a speaker cabinet, that is, the so-called "stack", and a combined amplifier (combo, combi) with a built-in speaker/speakers.

Most manufacturers produce both combos and stacks, sometimes even using the same design elements. The main reason for separating the amp and cabinet is purely practical, since guitar amps are usually quite, very heavy. Guitar cabinet designs typically use ten- or twelve-inch speakers, and a 2x12" cabinet (i.e., two 12-inch-diameter speakers) is the limit for a combo amp. Stacks, however, can contain one or more 4x12" cabinets. . Think of Jimmy Page or Eddie Van Halen on stage and immediately think of a huge Marshall stack with two 4x12 cabinets." Increasing volume levels at concerts in the 70s and 80s eventually led to the proliferation of real guitar "walls" on stage, although (I’ll tell you a secret) in fact, out of the entire “wall”, often only one cabinet is actually microphoned and output to the portals, the rest are pure props!

There is also a slight difference in sound and "feel" between a stack and a combo. The point is not in lower volume (some combos sound very loud even for large concerts), but in the feeling of greater “solidity”, integrity, especially in the low-frequency range. A similar effect occurs due to the synchronous movement of four or more speakers and the resulting sound wave.

Another advantage of the stack is the fact that some of the speakers are at the level of the musician's ears. If the amp on stage is turned towards the audience, sometimes it becomes difficult for the guitarist to hear his own sound. This is especially noticeable when working on small stages, when the cymbals of a drum kit may be closer to the guitarist’s ear than a low amp standing on the floor! This situation often leads to guitarists unnecessarily setting their amp volume too high. To improve the situation, you can place the amp on a corner stand, but for large amps this solution is unsafe.

Finally, a stacked set is much more flexible simply because you get a different sound when you change cabinets. The sound is influenced by a large number of factors, including the actual speaker model, cabinet design (open or closed), etc.

If the listed advantages of the stack do not make the right impression on you, read the information in the review dedicated to the choice of combos.

6. Types of cabinets

As we just said, the choice of cabinet affects the sound no less than the choice of the amplifier itself. The main factors here are cabinet design and speaker configuration and type. However there are others important parameters, affecting the sound. This includes the type of wood, the internal design of the body, and even the material of the front mesh.

Most cabinets use multiple twelve-inch speakers. A classic guitar stack contains one or two 4x12" cabinets - the second cabinet is usually connected for more serious gigs. 4x12" cabinets are usually available in two versions - with a straight or angled body, the latter with the top speakers directed forward and slightly upward. As standard, a beveled cabinet is installed on top of the stack to produce a larger sound angle.

1x12" and 2x12" cabinets are also very popular - they can be used when you need to imitate the sound of a amp, and they are better suited for small format performances.

7. Conclusion

Although other options exist, the stack remains to this day the most popular among rock musicians and the most flexible guitar amplification kit available. The variety of amps and cabinets available today is simply mind-boggling, and purchasing a real stack now won't break a huge hole in your budget.

It is worth noting that tube amplifiers require increased attention compared to transistor ones. Most of them have what is called a passive mode (Standby), and, unlike the useless energy-saving features of consumer electronics, this mode is extremely important. Tube amplifiers should always be turned on in passive mode and only after 30 seconds switch to active mode, since the tubes must warm up before the sound signal is given. When disconnecting, repeat this procedure in reverse order.

Most modern electronic devices do not require special care; they work until they break. However, this will not work with tube amplifiers - even if the amplifier works normally, it needs maintenance, at least once a year. This is done to preserve the sound, as well as to avoid unexpected failure of the tubes. In some amplifier designs, tube failure can damage other circuit components, such as the output transformer or speaker.

Thank you for taking the time to read our review and we hope that you are now much better prepared for the difficult process of choosing your new guitar amp!