Headphone amplifiers with button lock

Child lock

— the ability to block the amplifier control buttons — so that the device will not respond to pressing them.

This function is found exclusively in portable devices (see "Type"): such amplifiers are often carried in a pocket or bag, where there is a high probability of accidental pressing. Accordingly, so that these presses do not knock down the set settings, the design provides for blocking the buttons. The lock itself, usually, is controlled in a special way, which practically eliminates the possibility of accidentally turning it on or off — for example, by simultaneously pressing two buttons for a few seconds.