Guitar Amps & Cabs: specifications, types

General device type.

Nowadays, on the market you can find both ready combo amplifiers, and separate components for them — cabinets(including active and amplifiers (heads). Here is a description of each of these varieties.

— Combo amplifier. Combined guitar amplifiers in the traditional sense of the word. Externally, such a device is usually a characteristic box with a built-in speaker, inputs for connecting a guitar (often several guitars) and other signal sources, controls for adjusting the sound, and in most cases also handles or other devices for easy carrying. Inside are a speaker, two amplifiers (pre-amp and power), as well as electronic circuits designed primarily to process the incoming signal from the instrument's pickups. Thus, a combo amp includes everything you need to provide the full sound of a guitar of one type or another (see "Intended Use"). The set of settings, effects (see below) and other special features in such devices can be different — from the simplest to the most extensive. The same goes for power: small “amps” are designed mainly for home use, more powerful ones can be used at rehearsal facilities and concerts in relatively simple conditions — for example, in a pub, club or right on the street. Well, anyway, it is the combo amplifier that will be the best option for a novice guitarist who is...just mastering the instrument and equipment. But for large mass events, not combo amplifiers are better suited, but the so-called stacks — systems from a separately selected cabinet and head (see below for both).

— Cabinet. A cabinet is a separately made specialized speaker (speaker in a cabinet), designed primarily for use with a guitar amplifier (usually a separate “head” — see below). The cabinets do not have their own inputs for the instrument (with a few exceptions — and in such cases the speaker is used only to switch the signal to an external amplifier), power amplifiers — too, so such equipment is not designed for independent use in principle. And from more traditional acoustics, such speakers differ in additional optimization specifically for the sound of a guitar / bass (depending on the purpose). At the same time, the cabinet can have several inputs (see "Connection") and be used for several instruments at once — for example, solo and rhythm guitar at the same time.
Note that most cabinets have a fairly high power — from 100 W and above — and are intended mainly for concert use as part of a "stack" (a system of one or more speakers and a "head" amplifier installed on it).

— Active office. A rather rare and specific type of cabinets described above are guitar speakers, supplemented by built-in power amplifiers (and sometimes preamps). In fact, they are a simplified version of combo amplifiers — with a minimum set of adjustments (or even without them at all), but having at least the ability to work with line-level sound coming from the preamplifier to the line input, and in some models — also the possibility of direct connection guitars to the instrumental input. At the same time, most active cabinets have fairly powerful built-in acoustics (200 W or more), and sometimes also the ability to connect additional passive speakers. Such devices are mainly used as concert equipment; among other things, by connecting an active cabinet to the main “amp” or “head”, you can noticeably unload the main guitar power amplifier and achieve high volume without significant loads on the equipment.
Another, even more specific type of active cabinets are compact speakers designed to work with guitar amplifiers, which were originally designed exclusively for outputting sound to headphones. The level of the signal given out by such a device to the "ears" is comparable to the level of a linear signal; accordingly, additional amplification is required for playback through the speaker — which is provided by the hardware of the active cabinet.

— Amplifier (head). Separately made guitar amplifiers, not equipped with built-in acoustics. Traditionally, such devices are used in the "stack" format — in combination with a cabinet (see above) or a pair of cabinets; in this case, the amplifier is usually placed directly on the speaker (a "stack" of speakers), hence the slang name "head". If desired, other types of acoustics can be connected to the amplifier, however, cabinets remain the main purpose anyway. In general, a separate “head” in some situations is a more justified option than a solid combo amplifier. So, one of the main advantages of such devices is that you can choose speakers for them at your discretion; and if you already have a cabinet or other suitable acoustics, buying a “head” allows you not to overpay for extra equipment. The second advantage is that many stand-alone amplifiers are very advanced, with a wide range of features and/or high output power. In combination with the freedom of choice of acoustics mentioned above, this makes such equipment an perfect option for professional use (primarily for concerts). However, fairly simple and inexpensive “heads” are also produced, designed for beginner musicians and amateurs.

The instrument for which the amplifier is intended.

In general, the meaning of this paragraph is quite obvious, we note only a few nuances. So, it hardly makes sense to use an “amp” for an acoustic guitar with an electric guitar, and vice versa — these are two fundamentally different instruments with different initial sound characteristics. In addition, combo amps for electric guitars are quite often equipped with a set of additional effects, including distortion or overdrive (see "Effects"), although there are many models without such functions. But in devices for “acoustics”, although effects are also found, they are not so “radical” and are intended mainly for easy sound processing, and not for its fundamental distortion. In bass amplifiers, in turn, it may be possible to connect an active electric guitar and work two instruments at once through one “amp”.

The type of device is determined by the element base — the main type of parts on which the power amplifier circuits are built. Accordingly, this parameter is relevant only for equipment with such amplifiers; for cabinets (see "Type") it is not indicated.

The most popular nowadays continue to use traditional types of amplifiers — transistor and tube. Digital models are noticeably less popular, and hybrid solutions are rare at all. Here is a detailed description of each of these options:

— Transistor. Amplifiers of this type are relatively simple and inexpensive, while being able to provide quite acceptable sound quality (although, of course, everything depends on the class). It is the “transitor” that is recommended for beginner guitarists as the first “combo”, although there are quite advanced models among such devices. Of the unequivocal advantages of transistor circuits, one can name the durability of the components and the ability to easily transfer frequent carrying from place to place. As for the sound, in such devices it turns out to be more “dry”, “flat” and “cold” than in tube models, which many consider to be a clear disadvantage. At the same time, in the case of electric guitars, even this is quite enough for initial training, rehearsals and not very “fancy” performances; in addition, some transistor ampl...ifiers use specific signal processing to give the sound a tube-like sound. And combo amplifiers for acoustic guitars are overwhelmingly made with transistors.

— Lamp. Historically, the first type of amplifier, which, nevertheless, is still considered almost the standard when it comes to electric guitar (tube circuits are practically not used for acoustic guitars). The main advantage of such devices is the notorious “warm tube sound”, a characteristic soft, warm and at the same time rich coloring of the sound. At the same time, we note that the level of distortion in tube circuits is higher than in transistor circuits, however, these distortions are more pleasant to the ear, in many respects they provide the mentioned coloring. The widespread use of tube amplifiers is hindered primarily by their high cost — several times higher than that of transistor amplifiers with similar characteristics. In addition, among the disadvantages of such devices, it is worth noting the delicacy (the lamps do not tolerate shocks and shocks), the rapid wear of the lamps and the need for their regular replacement, as well as the need for warming up after switching on. However, professional musicians prefer to use mainly tube devices.

— Digital. Chip-based amplifiers using digital audio processing. The main advantage of such devices is the extensive possibilities for modeling sound and providing various effects. In particular, there are many models that copy tube amplifiers: the imitation is very reliable, and sometimes almost indistinguishable from the original. At the same time, digital models are devoid of many of the shortcomings of lamp technology: they are simpler, cheaper, more durable and more resistant to shock and shock. At the same time, digital processing is considered to take away personality from the sound, and many high-end audio enthusiasts are suspicious of digital solutions.

— Hybrid. Hybrid devices are devices that combine transistor and lamp circuits; usually a preamplifier is made with a tube, and a power amplifier is made with a transistor. In fact, this is a compromise between purely tube and purely transistor models, which allows you to combine the advantages and partially compensate for the shortcomings. Thus, hybrid solutions are noticeably cheaper than lamp solutions, they are lighter, more compact, less delicate and have fewer lamps that require regular replacement. And the sound at the same time turns out to be softer, cleaner and “warmer” than that of transistor analogs. At the same time, not many musicians choose such a compromise: those who strive for the highest quality and reliable sound prefer to spend money on tube equipment, and undemanding users (such as amateurs and beginner guitarists) are quite satisfied with transistor models. Therefore, there are relatively few hybrid models on the market.

Rated power of the device.

Let us recall that in acoustics the rated power is the highest average (root mean square) power of a sound or signal that a device can produce for an indefinitely long time. Individual volume jumps can be several times higher than this indicator, but the key characteristic is the average value. But the specific meaning of this parameter depends on the type of equipment (see above). So, for combo amplifiers, this paragraph usually gives the power of the built-in speakers; The capabilities of your own amplifier, by definition, correspond to this figure, so for such equipment the rated power determines solely the overall sound volume. The power of the acoustics is also indicated for cabinets, but here another point becomes relevant - compatibility with an external amplifier (primarily the “head”). The output power of this amplifier should not be higher than the rated power of the cabinet to avoid overloads; and ideally, these characteristics should match - this will allow you to use the speaker at full power without sound distortion.

For the head, accordingly, this paragraph provides the rated output power, which determines the ability of the amplifier to operate with a specific cabinet or other speakers. However, it is worth noting that the maximum possible power value is indicated as the nominal value for heads, which is not always achieved. Thus, many models provide several sound outputs - for passive acoustics with different...impedances (remember, standard impedance values are 2, 4, 8 and 16 Ohms); and the higher the impedance of the connected speaker, the lower the actual power will be. Other heads have the ability to limit the maximum power - for example, so that at the maximum level the device produces not 100 W, but 50 W or even 25 W. Sometimes these features are combined in one device.

In any case, when choosing according to this indicator, it is worth taking into account the features of the planned use of the equipment. For example, it hardly makes sense to purchase even a 40-watt “combination” for practicing at home - for these purposes 15 watts, or even less, will be quite enough. And if we are talking about a tube device, then in our example the maximum recommended power will be only 5 W - the specificity of tube circuits is such that with the same rated power they are more effective than transistor ones in terms of audibility. For rehearsals in a group without a drum kit (for example, two guitars plus a bass), a higher power is desirable, about 40 “transistor” watts, and if there are drums, at least 60 watts. Transistor devices with a power of up to 150 W and tube devices with a power of up to 40 - 50 W are suitable for specialized rep bases and concerts in relatively small rooms, and higher figures are found mainly in equipment for large-scale events. Detailed recommendations regarding optimal power for certain conditions can be found in special sources.

It is worth mentioning bass amplifiers separately: it is believed that for normal coordination with each other, the power of a bass “combination” should be twice as high as the power of a guitar one.

The impedance of the speaker(s) installed in the amplifier.

Impedance is the resistance to alternating current — that is, the current flowing when an audio signal is applied. This impedance affects the compatibility of the speaker with the power amplifier: if the impedance is too low, sound distortion occurs, if the impedance is too high, the volume is reduced. However, in combo amplifiers, this parameter is most often given as a purely reference: such devices have their own power amplifier, which, by definition, is designed for the impedance of the “native” speaker, and separately, with extraneous components, the speaker and amplifier are not used.

The audio frequency range supported by the device.

For guitar combo amplifiers and separate "heads" (see "Type") this parameter is usually not specified. This is due to the fact that such equipment is usually well optimized in terms of frequencies for its type of instrument (see "Intended use"), for other sound sources (for example, vocals) it is used relatively rarely, and if used, then an extensive frequency coverage, usually , is not particularly important. But separate cabinets are often used for several sound sources at once with different frequency coverage; so for them the frequency range is important and is often specified in the characteristics.

Theoretically, the wider this range — the more complete the sound produced by the device, the lower the likelihood that some part of the original sound will be cut off. However, in fact, when evaluating this parameter, it is worth considering the specific specifics of the use of the cabinet — namely, the frequency characteristics of the original sound sources. For example, the main range of a bass guitar is in the range from 41 to 250 Hz, but overtones (additional high-frequency vibrations that form the overall colour of the sound) usually reach 8 kHz; for acoustic and electric guitars, the lower limit of the main range is standardly 82 Hz, the upper one is 1175 and 1570 Hz, respectively, and the overtones are 12 kHz in the first case and 5 kHz in the second. And the minimum range required for a full vocal...transmission is from 40 Hz to 15 kHz; however, if maximum reliability is not required, more modest indicators are quite enough — from 80 Hz to 10 kHz.

Note that in guitar cabinets, the lower limit of the range is often lower than the mentioned 82 Hz — at the level of 70 Hz, or even 60 Hz. This allows you to maintain efficiency with a reduced tuning of the instrument. But in models for bass guitars, the lower limit of the range, on the contrary, is somewhat overestimated (from 50 to 70 Hz). This is not an unequivocal disadvantage: when equalizing the bass (tuning the sound in frequency bands), frequencies up to 150 Hz, usually, are greatly attenuated — their too high volume leads to “blurring” of the sound, worsens its clarity. And the lowest part of the range “up to 150 Hz” in most cases can be completely drowned out without a noticeable effect on the final sound quality.

As for the upper limit of the range, it is anyway higher than the main frequency of the instrument. So the difference in this parameter primarily affects the number of overtones transmitted, and in the presence of a multiband equalizer, it also affects the ability to fine-tune the sound: the higher the border, the greater the range of overtones available for adjustment. Also note that an extensive frequency range, which noticeably overlaps the overtones, does not in itself improve the sound quality, but is often a sign of a rather advanced device with the appropriate capabilities. Therefore, such figures are often indicated for advertising purposes.

It is also worth remembering anyway that the actual sound quality in a cabinet is determined not only by the frequency range, but also by a number of other parameters (including the characteristics of the amplifier used). So extensive coverage does not necessarily mean high-quality sound (and vice versa — with a narrow range, the sound quality may well be more than decent).

The number of speakers provided in the design of the device.

This parameter is indicated in cases where there is more than one speaker. Its meaning may vary. Thus, in some models several speakers are provided to be divided into frequency bands (see “Number of bands”); in this case, a small high-frequency emitter can be installed directly in front of the low-frequency one (the so-called coaxial circuit). In other devices, several speakers of the same type are used to provide the necessary sound power - for a number of reasons this is preferable to installing a single powerful speaker.

The number of bands provided in the combo amplifier. Indicated in cases where there is more than one lane.

The frequency band is called a certain part of the total frequency range, for which its speaker (or several speakers of the same type) is responsible. The division into bands makes sense from those considerations that for different frequencies (low, medium, high) the requirements for speakers will also be different: in particular, the lower the frequencies, the larger the radiator should be. Accordingly, the use of specialized speakers improves the overall sound quality of the combo.

In modern combo amplifiers, which are divided into bands, there are most often two bands — HF and LF / MF. This is considered sufficient for most cases. It is extremely rare among advanced models to meet three-band devices (HF, MF, LF), and more are considered technically unjustified.

The diameter of a specialized high-frequency speaker ("tweeter") installed in the amplifier.

The diameter of the speakers is traditionally indicated in inches. For tweeters, it is usually small — about 1 – 2 ", this is due to the peculiarities of the frequency range.

The diameter of the specialized mid-range driver installed in the amplifier.

This parameter is indicated only in models with a division into three frequency bands (see "Number of bands"). The size of the midrange driver in such devices is somewhere in the middle between the size of the tweeters and woofers.

The diameter of the woofer or woofer installed in the combo amplifier. The specific value of this parameter may be different, depending on the number of lanes (see above). In three-way systems we are talking about bass dynamics, in two-way systems — about the dynamics responsible for low and medium frequencies; and if the amplifier does not have band separation, this paragraph indicates the diameter of the main radiator.

In general, the larger the radiator, the louder it can sound and the richer the bass from such a speaker is. At the same time, we note that the speaker diameter is selected by the manufacturer based on the power of the built-in amplifier and the expected sound volume. So the main indicator when choosing is still the rated power, and the size of the speaker is more of a reference value.

The number of channels provided in a combo amplifier or a separate “head” (see “Type”).

This parameter is specified only if the device has more than one channel. The channel in this case can be described as a kind of “path” for the audio signal, which has its own specific set of settings. If there are several such “paths,” then each of them can be configured at your discretion and you can switch between sound options with just one click of a button (in extreme cases, by switching the instrument to another input). The most typical example of using this function looks like this: one channel is used for clean sound, and the second is used for “overdrive” using the built-in distortion or overdrive (see “Effects”). Without channel separation, the sound would have to be changed either by reconfiguring the amplifier (setting the parameters again each time, which is simply inconvenient), or by using external “gadgets” (and this is not always the best option for a number of other reasons).

As for the number of channels, in multi-channel models there are most often just two of them - this gives the mentioned additional capabilities and at the same time does not particularly affect the cost of the device. This option is optimal for beginning musicians, but is also found in professional equipment. Increasing the number of channels allows for more advanced options for preset settings (for example, “clean ringing”, “clean warm”, “C...runch” and “Overdrive”), but significantly complicates and increases the cost of the design. Therefore, the higher this number, the fewer models with such characteristics are presented on the market. The maximum value found in modern guitar amplifiers is 6; a similar amount can be found in individual professional models, mainly with a digital element base (see “Type”).

Type of equalizer provided in the device design

An equalizer allows you to change the volume of a separate part of the sound range (frequency band), thus changing the color of the entire sound. This is one of the most important functions related to audio settings; therefore, it can be provided directly in the guitar amplifiers themselves. And the type of equalizer is indicated by the number of bands available for adjustment.

The more of these bands, the more accurately you can adjust the sound, but the more complex and expensive the equipment becomes. In light of this, the simplest option involves only 2 bands - low and high frequencies; Often such an equalizer takes the form of two separate knobs for adjusting the bass and treble levels. At the same time, we note that similar functionality can be found in both budget and high-end guitar amplifiers: in the second case, it is assumed that if finer adjustments are needed, you can use external equipment. However, three-band solutions (low, mid and high frequencies) are the most popular these days: such an equalizer provides quite extensive possibilities for adjusting the sound and is relatively inexpensive (and if finer adjustments are required, you can use external equipment). 4-band equalizers are noticeably less common, but are also quite popular (including in inexpensive devices); and some models p...rovide 5 or more (up to 12) adjustment bands.

The presence of an analogue modeling function in the amplifier.

The meaning of this function lies in the fact that with the help of analogue sound processing, the amplifier changes the sound in a certain way, giving it one colour or another. So, many models provide modeling the sound of certain classical guitar amplifiers and/or cabinets; of course, there is no question of absolute similarity, but sometimes a copy can be almost indistinguishable from the original. Other models built on transistors (see "Type") can copy the sound of tube technology. And the analogue method of sound processing for such modeling was chosen because it allows you to do without unnecessary conversions (unlike digital); this has a positive effect both on the quality and atmosphere of the sound, and on the price and reliability of the equipment.

The specific features of analogue modeling in each case should be clarified separately, however, anyway, it significantly expands the functionality of the amplifier and provides additional features for fine-tuning the sound.

The presence of a block of digital effects in the amplifier. Note that this function can be provided in any models, not only digital ones (see "Type").

As the name implies, this function allows you to change the sound in one way or another, sometimes quite drastically. See below for the most popular effects; their specific set may be different, it should be specified separately in each model. Here we note that without this function, additional external “gadgets” will be required to work with effects.

The presence of a phase regulator in the design of the amplifier.

When using the device simultaneously with other sound sources (for example, when a guitar and bass “amps” are working side by side), a situation may arise when the sound from these devices is out of phase. This can lead to a noticeable deterioration in sound and a decrease in its volume. You can correct the situation by adjusting the phase on one of the devices; This is what this adjustment is for.

The presence in the amplifier of the regulator "Gain".

This control is responsible for adjusting the intensity of overdrive when using effects such as distortion or overdrive. Thanks to him, you can change the severity of these effects — from almost complete absence to pronounced distortion, which has little to do with a clean guitar sound.

Built-in effects provided in the combo amplifier. You can also achieve various effects with the help of external “gadgets”, however, such gadgets need to be searched for and connected separately, while built-in effects are available immediately and without unnecessary settings.

— Overdrive. Distortion in the form of a characteristic electric guitar "buzz" at low frequencies and "howl" at high frequencies, a little softer than distortion. Popular, in particular, in hard rock.

— Distortion. Sufficiently hard and sharp distortion, similar in sound to overdrive, but more intense and brighter. It is widely used in various styles of metal, and is also found in rock.

— Reverb. An effect based on simulating multiple decaying echoes from each sound. Depending on the duration and intensity of repetitions, it can give the sound a different colour. Used as an artistic device; among other things, it can create the effect that the guitar sounds in a certain room (concert hall, room with stone walls, an open area in the mountains, etc.). Note that the reverberation can be adjusted both by individual parameters (intensity, echo duration, etc.), and by selecting a preset set of parameters (for example, “sharp sound in the room” or “soft sound in the hall”).

— Tremolo. Tremolo is basically a trembling effect that res...ults from small and quick fluctuations in the volume of each note. Sometimes this term means vibrato (see below) — to the point that the manufacturers of guitar amplifiers themselves mean the effect of vibrato by the tremolo effect, and vice versa. So the specifics of this effect in each case should be clarified separately. Anyway, the tremolo can be "fixed" or adjustable in depth (range of volume change) and speed (jitter frequency).

— Vibrato. Another effect of "jerking" sound, which is often confused with tremolo (see above) — to the point that both these terms are used as identical. However, this is not true; the difference lies in the fact that vibrato is carried out due to the rapid fluctuations of the note not in volume, but in frequency. A similar effect can be achieved on the guitar itself by "pulsating" the strings, but using the amplifier's built-in instrument is much more convenient in most cases.

— Chorus. An effect designed to simulate the choral sound of an instrument. To do this, the amplifier copies the sound of the guitar and plays several copies simultaneously with the original signal, slightly shifting them in time (about 20 – 30 ms with a constant change) and frequency. However it is impossible to achieve a full-fledged choral sound in this way, but the effect is quite original in itself.

— Delay. A specific type of reverb (see "Reverb") that has become widespread as a separate effect. Delay simulates a clear single echo from the sound being played; for this, the original signal is copied and reproduced with a certain time delay (at least 50 ms).

In addition to those described above, other effects can be found in modern guitar combo amplifiers, in particular:

— Flanger. The effect is reminiscent of the whistle of a jet engine; it is often compared to a plane taking off. It is created similarly to the Chorus described above, differs from it in a shorter delay time and the presence of feedback.

— echo. Another kind of reverb, similar to delay (see “Delay”). It differs in that in this case the echo is reproduced repeatedly.

— Octaver. An effect in which a copy of it is added to the signal, shifted by an octave or two.

— Wah wah. An effect that produces a characteristic "croak" sound.

The number of instrumental inputs provided in the device.

These inputs, as the name suggests, are used to connect instruments—in this case, guitars and basses. The audio signal from the pickups has its own specifics, so a microphone or line input is not suitable for it - separate connectors are required. Most often, such connectors are made in the form of Jack 6.35 mm sockets; and their number usually corresponds to the number of instruments that can be simultaneously connected to the device. However, in models with multiple inputs, a more specific option can be used: switching between amplifier channels (see “Amount of channels”) by physically moving the guitar plug from one connector to another. This format of work is quite rare, but can also be used; so it wouldn’t hurt to clarify the features of a device with multiple inputs separately.

However, amplifiers for 1 guitar input are the most widespread nowadays - after all, a “combination” or “head” is most often purchased just for one instrument. Solutions with two inputs are also quite popular. In some models, this number can reach three or even four, but these are quite rare options - using your own amplifier for each guitar is usually more convenient and smarter than connecting several instruments to one device at once, and such “multi-charging” is very expensive.

Connectors for connecting a signal from the “head” or other external power amplifier, provided in the design of the cabinet (see “Type”).

First of all, compatibility with a specific “amp” depends on this feature: for normal compatibility, the output type on the amplifier must match the type of input on the speaker. At the same time, guitar cabinets often have several inputs for an amplifier at once — and these can be either the same type or different sockets. Such details are given in this clause; in this case, usually, the presence of several inputs means the ability to connect several external amplifiers at the same time, however, the possibility and features of the implementation of this function will not hurt to clarify separately. And here are the specific types of connectors that are relevant for modern cabinets:

— Jack. Connector for a Jack plug with a diameter of 6.35 mm. This connector is one of the most popular in modern audio technology: it is relatively compact and inexpensive, while providing a fairly large contact area and good reliability. On the other hand, in terms of connection quality, this connection method is still inferior to XLR and Speakon (see below). In addition, although the Jack standard is technically suitable for balanced connection (see "Combo (Jack / XLR)"), in fact this possibility is implemented extremely rarely — the vast majority of guitar cabinets are designed for the classic, unbalanced connection format using a two-pi...n plug . This connection is resistant to interference and makes it difficult to use long cables. Nevertheless, even such features are often enough for both domestic and professional use — for example, if the amplifier is installed nearby (and the guitar "heads", we recall, are placed directly on top of the cabinets), and there are no sources of interference nearby.

Combo (Jack/XLR). Combo input compatible with both 6.35mm Jack and XLR connectors. In fact, it is an XLR jack, in the middle of which there is an additional recess for a 6.35 mm plug. For more information about the Jack standard, see above — connecting to a combo connector does not differ in its properties from the usual one. As for XLR, it's a distinctive round plug with 3 pins and a metal sheath around them on the plug; such a shell is often supplemented with a lock that locks the plug in the socket, due to which this interface provides high reliability. However, its main advantage is that XLR cables and plugs usually work in the so-called balanced format. For such a connection, not two, but three wires are provided — relatively speaking, two signal and one common "zero"; and the input signal is processed in such a way that the interference induced on each wire from external sources is "in antiphase" and canceled out mutually. Thanks to this, a balanced connection allows high-quality and pure analogue audio transmission even with long cable lengths. On the other hand, for a number of reasons, the XLR interface (even in the form of a combo jack) is not popular specifically in guitar cabinets.

— Speakon. A specialized professional connector for connecting passive acoustics, widely used in concert equipment. Provides very high quality and tight contact, has a latch to prevent accidental shutdowns, designed for higher currents (and, accordingly, power) than the types of connections described above. In light of the last socket, Speakon plugs are also distinguished by high-quality insulation, which reliably protects current-carrying parts from moisture and human contact.
Note that such a connection can use a different number of contacts — 2, 4 or 8 (respectively, for one, two or four sound channels). The plug itself has a round shape, with contacts located along the circumference; however, a 2-pin plug can work with a 4-pin socket, but not vice versa, and 8-pin plugs differ in configuration and are not compatible with other varieties. In guitar cabinets, 2-pin connectors are the most popular — after all, such speakers are designed to work with one sound channel by default. And if it is supposed to be possible to “serve” several signal sources, then several connectors, respectively, can be installed. However, it's ok to clarify the specific configuration of this input separately.

— Firm. One or another original connector that does not belong to any of the standard options described above. A very rare option, found in single models of cabinets, designed for use exclusively with the "heads" of the same manufacturer that have the appropriate type of connection. The possibilities of the connector itself can theoretically be any, but in fact this option is found mainly in relatively low-power equipment designed for home and other similar applications — accordingly, the connection itself usually does not differ in particular "tricks".

The number of connectors for connecting pedals (footswitch), provided in the design of the amplifier.

The pedal is the most convenient way to quickly change amp settings and can be used while playing the guitar. The specific functions "tied" to the pedal connectors can be different: in particular, various effects can be turned on and off in this way (see above). Also, in different models, the number of connectors for pedals may vary: in most “amps” there is only one such connector, however, there are devices that allow connection of several “foot switches” at once.

The type of line input provided in the amplifier.

The line input is used to supply sound from an external source to a guitar amplifier (“amplifier” or “head”). In this case, the incoming audio signal is sent to the input of the power amplifier and through it to the built-in speaker or external cabinet. In any case, this function allows you to combine the “live” sound of the instrument with additional accompaniment: for example, you can connect a player with a recorded drum and bass part to the line input and learn the guitar part with accompaniment - or perform in a “one-man orchestra” format.

Different types of connectors can be used for line input:

— Mini-Jack (3.5 mm). A socket for a standard 3.5 mm mini-Jack plug. This interface is used mainly in portable audio equipment; Jack 6.35 mm and RCA are more popular in stationary devices.

— Jack (6.35 mm). A connector similar in design to the 3.5 mm mini-Jack and differing only in size. Actually, due to its size, this type of plug is practically never found in portable audio equipment, but is quite popular in stationary ones. Theoretically, a Jack type connector can be used for a balanced connection (see below), but in guitar combo amps a regular unbalanced input is more common.

- RCA. Connector for coaxial cable with tulip type plug. It is used exclusively in stationary audio equipment. A standard RCA input consists of two jacks (for...stereo sound, left and right channel), but in guitar combo amplifiers there is only one connector, since there is no point in using stereo in this case - one channel is enough.

— Balanced XLR. The characteristic connector is round in shape with three contacts and is quite large in size. The term “balanced” describes the specifics of signal transmission: it is carried out not through two, as with a standard connection, but through three wires, two of which operate in antiphase. Due to this, most of the interference induced on the wire is extinguished by itself, without the use of any special filters, which allows the use of long cables without compromising signal quality. Balanced connections are found mainly in professional audio equipment. As with the RCA described above, the standard XLR input includes two jacks (stereo left and right), but guitar amps use a simplified, single jack version.

Some combo amplifiers are equipped with several types of line inputs at once - for example, Jack and RCA. This usually means having separate connectors for each type. Theoretically, multiple inputs allow you to simultaneously connect several signal sources, but in practice this possibility should be clarified separately.

Type of microphone connectorprovided in the design of the amplifier.

The microphone can be used both for vocals and for additional guitar accompaniment. And the types of connectors for it can be as follows:

— Jack (6.35 mm). Also known as TRS. A connector similar to the popular mini-Jack 3.5 mm, which is larger in size. Theoretically, it can be used not only for normal, but also for balanced connection, however, the latter is rare in combo amplifiers (in general, this point should be specified separately in each case). Plugs under this connector are found in all types of microphones, from the simplest to the high-end.

— Balanced XLR. Characteristic round plug with three contacts; can be supplemented with a lock for a more secure fixation. And the essence of a balanced connection is that the sound is transmitted not through two, but through three wires — one zero and two signal, working in antiphase. Due to this, most of the interference induced on the wire is canceled directly at the input without any additional processing, and even with a long cable length, the signal is clear and of high quality. The XLR connector is found predominantly in high-end professional microphones.

-XLR/Jack. Combo jack suitable for both XLR and 6.35mm Jack; in fact — an XLR jack, in the centre of which there is a hole for Jack. Both of these connectors are described in more detail above. Also note here that XLR usua...lly uses a balanced connection, but the presence of such an opportunity when working through Jack should be specified separately.

Note that some high-end microphones (in particular, condenser ones) require a so-called. phantom power — additional power supplied to the connection connector. The presence of this function in the combo amplifier should be clarified separately.

The type of insert (send/return) provided in the combo amp.

In this case, a gap means a set of connectors for connecting an effects unit between the preamplifier and the combo's power amplifier. One of these connectors (preamp output) is usually labeled “Send”, the second (power amplifier input) is labeled “Return”. With such an interface, you can connect various "gadgets" to the combo amplifier, supplementing it with effects that were not originally provided for in the design (see "Effects"). And the type of gap determines the connection format of the "gadget". The options might be:

— Consistent. The simplest connection option: the “gadget” is connected directly between the preamplifier and the power amplifier, and the entire audio signal passes through it.

— Parallel. With this type of connection, the signal at the output of the preamplifier is divided: one part goes through the "gadget", the second — bypassing it. Both streams enter the mini-mixer, where they are again combined into one signal. Such a connection scheme is more complicated and somewhat more expensive than a serial one, but it gives more opportunities: the mixer allows you to change the ratio between the original and processed signal, thus adjusting the final sound. At the same time, in many models it is possible to completely turn off the original signal and feed only the processed stream to the power amplifier, as with the series amplificatio...n described above.

The presence of a preamplifier output(Pre-Amp) in the "combo" design.

A line level signal is supplied to this connector. Pre-Amp differs from the line output (see below) in that the signal level can be adjusted. The main function of such an output is to output sound to an external amplifier (or acoustics equipped with a built-in power amplifier).

The type of headphone output provided in the design of the amplifier.

Headphones will be useful especially in a situation where you can not make noise — for example, when practicing the guitar at a late time. And the options for their connection can be as follows:

— Mini-Jack (3.5 mm). Output for a standard 3.5 mm mini-Jack plug. This plug is equipped with most modern headphones, especially entry-level and mid-range. However, in terms of the quality and reliability of the connection, it is noticeably inferior to the larger Jack 6.35 mm (see below), so it is relatively rare in combo amplifiers.

— Jack (6.35 mm). The connector is quite large, designed mainly for stationary audio equipment. As the main connection method, it is rarely found among headphones, these are mainly professional models. At the same time, you can connect headphones with a 3.5 mm mini-Jack connector to such a jack using a simple adapter (in many “ears” such adapters are even included in the standard package); and the connection itself is tight, reliable and with a minimum of interference from the point of contact. Due to this, most "amps" use this type of connector.

The type of line output provided in the design of the combo amplifier.

This output, as the name suggests, provides a line-level analogue audio signal. In this case, unlike the preamplifier output (see above), the signal level at the line output is not adjustable. This interface is mainly used to connect recording devices, although it can also be used to output a signal to an external amplifier (in fact, in the absence of a Pre-Amp output, the only option for such a connection is a line input). And the types of connectors used for the line output can be as follows:

— Mini-Jack (3.5 mm). The classic "minijack" is small in size, but inferior to larger connectors in terms of reliability and connection quality; compactness in the case of combo amplifiers most often does not play a decisive role. That is why such exits are extremely rare, mainly in the most compact “amps”.

— Jack (6.35 mm). Connector, quite popular in stationary audio equipment, including pretty advanced. Theoretically, it can even provide a balanced connection (see below), but this feature is far from mandatory, its presence should be specified separately. Also note that a 3.5 mm mini-Jack plug can also be connected to such a jack using a simple adapter.

— Balanced XLR. The XLR output is a characteristic round three-pin connector with a balanced connection type. With this connection, the signal is transmitted over thre...e wires instead of two, and in a special way, due to which the interference induced on the wire is extinguished. This allows even fairly long cables to be used without sacrificing signal purity, making this type of connection suitable even for professional audio equipment. Actually, XLR is also considered a professional interface — both because of the ability to work with a balanced signal, and because of the rather large dimensions and increased reliability (connectors are often equipped with locks for fixing plugs).

— Jack/XLR. Usually, in this case, a combined connector is meant, combining a 6.35 mm Jack and XLR. On the features of both, see above; and the combo jack looks like an XLR jack, complete with a hole for a Jack plug in the centre.

Jack/RCA. The presence in the device of two linear outputs at once, with different types of connectors. See above for more details on the Jack interface. And RCA is a connector for a coaxial cable with a “tulip” plug; this is one of the most popular interfaces in entry-level and mid-range stationary audio equipment, but it is relatively rare in guitar amplifiers.

— Corporate. A proprietary connector that does not belong to any generally accepted standard. It is mainly used to connect equipment of the same brand as the combo.

The type of DI Out used in the device.

By itself, the DI (direct input) output is similar in purpose to the line output (see below): it is used to output an analogue audio signal from a combo amplifier or a separate “head” (see “Type”) to an external device. The differences are that the line output has a high or medium internal impedance and provides an unbalanced connection; as a result, the signal from such an output is quite sensitive to external interference, especially with a long cable length. DI, in turn, has a low impedance and balanced signal format, which makes it optimally suited for professional applications. A typical example of the use of such an output is connecting a guitar or bass through an amplifier to a mixing console in a recording studio or at a concert venue (a direct connection of an instrument is unsuitable for this purpose, since the instrumental output, similar to the linear one, has a high impedance). In the absence of DI Out, for such purposes, one has to either use direct boxes (a kind of adapters from high-impedance outputs to low-impedance inputs), or use microphones to sound the speakers of the combo amplifier / cabinet (microphones are high-impedance signal sources).

Separately, it is worth touching on the balanced connection mentioned above. For it, not two, but three wires are used — relatively speaking, two signal and one common "zero"; and the input signal is processed in such a way that the interference induced on eac...h wire from external sources is "in antiphase" and canceled out mutually. Thanks to this, the balanced connection allows high-quality and pure analogue audio transmission even with long cable lengths.

In fact, modern DI Outs in guitar amplifiers differ only in the type of connector, the options here can be as follows:

— Balanced XLR. The type of connector used in the vast majority of outputs of this format. This is due to the fact that it is the XLR interface that is most often used in audio equipment for balanced connection. The connector itself of this type has a round shape and three contacts (another number is possible, but in this case these options are not relevant), and the round “skirt” on the plug is often supplemented with a lock, which increases the reliability of the contact and prevents accidental disconnection.

— Jack. A standard 6.35 Jack type connector is usually three-pin. Theoretically, a similar interface can also be used for the balanced connection described above, and any standard cable with an appropriate Jack plug is suitable for such a connection. However, in fact, among guitar amplifiers, DI Out output with this type of connectors is extremely rare. And even in such models, such a connector can be a so-called “DI Out emulator” — in fact, a regular line output (even not always balanced), the signal from which imitates the sound of a microphone that sounds the speakers of a combo amplifier / cabinet.

Type of output (outputs) to the cabinet provided in the design of the device.

Let us remember that cabinets are specialized passive acoustics for guitar amplifiers; See "Type" for details. Accordingly, outputs to such acoustics, by definition, are available in almost all “heads” (see ibid.); The only exceptions are a few models that were originally intended for use with headphones and do not have full-fledged power amplifiers. In addition, this type of output is found in many full-fledged “combinations”, as well as some active cabinets. At the same time, the format of its use can be different: in some models, the external cabinet can work in parallel with the built-in speaker, in others you have to choose one thing. Be that as it may, this feature expands the capabilities of the combo amplifier, allowing it to be used not only with built-in acoustics, but also with other cabinets that have suitable characteristics.

In any case, the type of this output must match the type of input on the cabinet itself - otherwise the connection, at best, will require the use of an adapter, and at worst, it will be completely impossible. But here are the main options for such connectors that are relevant today:

— Jack (6.35 mm). One of the most popular connectors in modern audio equipment and the most common type of cabinet output in guitar amplifiers. This is due, in particular, to the fact that this connector is relativel...y small in size, and the cables for it are relatively inexpensive and are available everywhere. True, in a number of characteristics this interface is inferior to other standards described below. Thus, it does not provide a lock for additional fixation of the plug in the socket and is not suitable for high powers and currents (unlike Speakon). And a balanced connection (such as in XLR), although technically possible for Jack, is used extremely rarely in practice - guitar amplifiers and cabinets usually use two-pin connectors with a classic (unbalanced) connection. However, the need for more advanced connection options arises mainly in situations involving increased requirements for quality, power and/or noise immunity - in recording studios, large concert venues, etc. For other cases, the capabilities of this interface are usually more than enough.

- Speakon. A specialized professional connector for connecting passive acoustics, widely used in concert equipment. Provides very high-quality and tight contact, has a lock to prevent accidental disconnections, and is designed for higher currents (and, accordingly, powers) than XLR and especially Jack. In addition, Speakon sockets and plugs are also distinguished by high-quality insulation, which reliably protects live parts from moisture and human touch.
Note that such a connection can use a different number of contacts - 2, 4 or 8 (respectively, for one, two or four audio channels); however, the latter option is practically never found in guitar amplifiers. The connector itself has a round shape, with contacts located around the circumference; however, a 2-pin plug can work with a 4-pin socket, but not vice versa. It wouldn’t hurt to clarify the specific configuration of this output separately. However, in any case, the presence of Speakon is usually a sign of a powerful and advanced amplifier, designed primarily for concert use.

— XLR. A characteristic round connector with 3 contacts and a metal shell around them on the plug; such a shell is often supplemented with a lock, which additionally secures the plug in the socket. However, the main advantage of this interface is that XLR cables and connectors usually operate in the so-called balanced format. This connection format provides not two, but three wires - relatively speaking, two signal and one common “zero”; and the input signal is processed in such a way that noise induced on each wire from external sources is “out of phase” and cancels out each other. Thanks to this, a balanced connection allows you to transmit high-quality and pure analog audio signals even over long cable lengths. On the other hand, the connector itself is quite large in size, its presence inevitably affects the cost, and the real need for a balanced output to the cabinet does not arise very often. Therefore, this connector is not particularly popular.

— Jack/XLR. A combination of the two types of outputs described above in one amplifier. See above for details on each type; Let us note here that most often these are separate connectors, although another option is technically possible - a combined socket that allows the connection of both Jack and XLR. These nuances should be clarified separately. In any case, this combination makes the amplifier more versatile and means it has a balanced output (see “XLR” above); however, such versatility, as well as a balanced connection, are required in practice relatively rarely, which is why this combination has not become widespread.

— Speakon/Jack. Another combined option, which assumes the presence of the two types of outputs described above. It is slightly more popular than the Jack and XLR combination; We also note two more specific points. Firstly, in this case, different types of connectors are made exclusively in the form of separate sockets. Secondly, by the number of Jack outputs, you can determine the type of “speakon”: in this case, each 6.35 mm connector is responsible for one audio channel - accordingly, if there are two such outputs, then the only Speakon will also be two-channel (that is, four-pin).

The presence of a built-in looper in the amplifier.

Looper is a module that allows you to record and loop a specific piece of music. Using this function, you can, for example, record a rhythm guitar part directly into the “amp”, turn it on for playback and work out the solo part to the accompaniment played through the looper.

The presence in the combo amplifier of its own display. Often this is the simplest segment screen that can display numbers and some special characters; however, even such a screen provides additional convenience and allows you to easily monitor the operation parameters. And in digital models (see "Type"), more advanced displays can be provided that can display various textual and graphic information: the name of the selected channel, equalizer settings, etc.

The presence of a pedal (footswitch) in the scope of delivery of the combo amplifier.

The pedal is the most convenient way to quickly change amp settings and can be used while playing the guitar. At the same time, the specific functions of such a switch may be different, depending on the functionality of the “amp” itself: the pedal can turn certain effects on and off, switch the channel used, etc. These points should be clarified separately. Anyway, the presence of a footswitch in the kit eliminates the need to purchase such a switch separately, while the "native" pedal, by definition, will be optimally compatible with the amplifier.

The presence of a built-in compressor in the combo amplifier.

A compressor is a module that "compresses" the dynamic range of an amplifier, in other words, it reduces the difference in volume between the loudest and quietest sound. This provides improved sustain—that is, a note played and not muted sounds longer, at a more even volume, and with a slower decay than without a compressor. On the other hand, the use of this function slightly increases the level of extraneous noise and worsens the dynamics.

Compressors can also be provided in external equipment, but the built-in module is often more convenient: it is available “out of the box” and does not take up extra space.

The presence in the combo amplifier of autonomous power supply.

This feature allows you to use the device regardless of the outlets — for example, for outdoor performances. The source of autonomous power is most often replaceable batteries, for example, 6 AA cells; however, a built-in battery may also be provided. The first option is convenient because dead batteries can be quickly replaced with fresh ones, the second one is that the battery is initially supplied in the kit, and when it is discharged, it is enough to charge it, there is no need to spend money on buying new batteries.

Note that most self-powered models are relatively compact and low-power devices — powerful acoustics would require too expensive and bulky power supplies.

Possibility to mount a combo amp or cabinet (see "Type") at an angle.

This design feature means that the unit can be tilted slightly backwards with the speaker angled upwards. In some cases, this arrangement is optimal from the point of view of acoustics — for example, it allows you to send sound directly to the listener from a small speaker installed on the floor without additional stands. Most often, for installation at an angle, a special beveled shape of the body is provided. Moreover, if the height of the device is not very different from the width (or noticeably less), then such a device is enough to simply tilt back relative to its original position; but if the case has a pronounced vertical layout, and its height is noticeably greater than the width, it will most likely have to be laid on its side to place it at an angle.

Another option for implementing this function is a retractable or folding support from below, in the front; however, it is somewhat more complex and less reliable, so it is used less frequently.