Features
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”.
Type
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.Number of channels
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 makes it possible to provide more advanced options for preset settings (for example, “clean ringing”
..., “clean warm”, “Crunch” and “Overdrive”), but it 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”).Equalizer
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 looks like 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 provide
...5 or more (up to 12) adjustment bands.Analogue simulation
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.
Gain
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.
Effects
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.Line input
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.Microphone
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.