Headphone amplifiers with XLR headphone output
XLR
— amplifiers with at least one XLR headphone output. The specific number of such connectors and the presence / absence of other outputs should be specified separately; also XLR jacks can have a different format, this point is described in more detail belowXLR is a professional connector with a characteristic round shape, contacts in the form of pins (“pins”), and often also a latch on the rim for additional reliability in connection; this connector is used for the so-called balanced headphone connection. Without going into details, the general principle of balanced connection can be described as follows: due to the special design of the cable, the interference that occurs in it due to external interference is extinguished “by itself”. This has a positive effect on the purity of the sound and allows the use of even long wires without the additional risk of distortion. On the other hand, in the case of headphones, the need for such a connection arises relatively rarely, and very few “ears” with an XLR plug are produced — mostly high-end professional models. So, in amplifiers, outputs of this type are used infrequently — mainly in stationary devices (see "Type") of a premium level.
Regarding the type of connector, it is worth noting that a relatively rare four-pin XLR is most often used as a headphone output, in some models with a reduced jack. This type of output is standard for balanced headphone connection: it makes it possible to transmit both stereo channels through one connector, which eliminates the need for extra sockets / plugs and has a positive effect on the compactness of both the amplifier and the “ears”. However, there are also amplifiers where a pair of three-pin XLRs plays the role of a balanced headphone output. At the same time, such connectors can be physically combined with 6.35 mm Jack outputs — in other words, a 6.35 mm jack is built right into the centre of the XLR connector. This makes the design more compact, but does not allow the use of both types of connectors at the same time.