Theory And Construction of Mic "Splitters"

The Jensen JT-MB-x series transformers, commonly called "mic splitters", are designed to "bridge" the output of a 150 S to 200 S microphone. The "MB" in the part number stands for Microphone Bridging. They are available in 2, 3, and 4 winding versions and are generally used to provide additional, isolated outputs from a single microphone. The microphone is directly connected to the first preamp input, which provides "phantom power" if required, and also connected to the primary winding of the MB transformer, which now "bridges" the mic to first preamp line. The direct output is the ONLY output which will pass phantom power to the mic. The MB transformer secondary windings are then connected to additional preamp inputs. Since the transformer magnetically couples the signal to each winding, each preamp now "sees" the microphone's output signal while having no problematic direct connection to the other preamps. To a preamp, each isolated MB transformer output "looks like" a normal floating (ungrounded) microphone.