A phantom powered preamp for use with a microphone cartridge having a unique mechanical interface. The unique mechanical interface allows the phantom powered preamp to function with both ¼ and ½ inch microphone cartridges. The phantom powered preamp including a housing base having a PC board assembly and a connector, the PC board assembly being electrically coupled to the connector; a preamp tip having an adapter and a guard tube, the PC board assembly extending from the housing base to the preamp tip and being electrically coupled to the adapter and the guard tube, the adapter being configured to be electrically coupled to the microphone cartridge, the guard tube being configured to surround a portion of the PC board assembly within the preamp tip; and a first converter being configured to releasably engage the preamp tip or the housing base to reduce edge diffraction.