Microphone output voltage is often measured in units, sometimes tens of millivolts. Therefore, this signal is very weak, besides its quality deteriorates during transmission over long cables. Is virtually impossible connect to multiple consoles a microphone and get a good sound. Slayer is often quoted on this topic. Let's imagine the following situation: there is the task of voice concert at the stadium, where the length is 100 meters Multi, and acting requires a monitor console. In this situation, it is recommended to use separate mic preamps (rack preamps). By purchasing several rack preamps, you'll see that got rid of the set smaller problems. In the first mic preamps are an ordinary microphone amplifier.
It has a low impedance balanced input with adjustable sensitivity and the possibility of phantom power +48 V for condenser microphone. Linear preusilitel with adjustable gain (2) has unbalanced high impedance (100 ohms to 1 megohm) input, an employee at the same time the impedance converter (Di-box), that allows you to connect to it Pickup adapterizovannyh tools, including piezoelectric transducers of guitars, pianos, etc. The combination of these two vhodnyhblokov provides the opportunity to work with any source of signals. In the above case, instead of In order to take away a weak signal for long cable different mixers, you can connect a microphone is much more short wire to the preamplifier, which stands on the stage. If this all turns out beautiful clean sound, not eaten by long cables.
From the stage to a mixing console with a powerful signal to go out, so there will be no loss even with a powerful output. A number of independent output enable to distribute the signal across multiple users and exclude their interaction. An additional advantage of a separate microphone amplifiers is the use of low-cost, linear mixing consoles without built-in microphone amplifier, because recording of modern music with lots of electronic sounds often enough to have a 4.3 mic, with the remaining microphone inputs in a large panel expensive not used, and the money to purchase them are spent in vain. As a result, we get a great sound!