Audio Technology / Recording / Microphones / Cabling and phantom power ...

Cabling is a common cause of recording problems. In order to avoid noise (60 Hz hum) and phase problems, it is recommended to use professional quality balanced XLR (two conductors for the signal with neither connected to the shield) cables to connect the microphone to the pre-amplifier PHOTO>> . If the pre-amplifier does not have balanced XLR inputs, one should use a balanced to unbalanced transformer (Ebtech Line shifter PHOTO>> , CP8201 In-Line Transformer). The transformer's primary side matches the impedance of the microphone and is balanced, while the secondary side is unbalanced and has high impedance that matches most unbalanced pre-amplifier inputs. Condenser microphones require a 48 V phantom power. While some microphones, such as AKG C1000 can work from an internal battery source, others require an external phantom power supply, which many good pre-amplifiers and mixing consoles come equipped with.