Audio Technology / Recording techniques/ Pre-amplifiers...

The main function of a pre-amplifier is to accept a very low-level signal (such as that from a microphone) and amplify it without adding noise. Good pre-amplifiers are not easy to build, as they have to be immune to all kinds of potential noise and signal distortion. It is, therefore, important to use the best possible pre-amplifier, particularly one that has a fairly high gain, broad dynamic range, high SNR, phantom power, and balanced XLR inputs. Good field pre-amplifiers are particularly hard to find. Sound Devices MP2, USB Pre, and Shure FP 23 ( PHOTO>> ) are among some of the best, yet affordable field pre-amplifiers. The gain on the pre-amplifier should be set relatively high, but the speaker's voice amplitude range should be tested first to avoid signal overload. If intensity measurements are not indented, a soft compressor-limiter may be used to maximize amplitude and help prevent signal clipping.