Footswitch
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.
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.Headphones
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.
Cabinet output
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).
