The e3002 is a dual-diaphragm, multidirectional condenser microphone with CAD's proprietary Equitek amplifier circuitry. The version shipping today, the e3002, is a second-generation design manufactured overseas to CAD's specifications. The original e300 was manufactured in the U.S. and had slightly different specifications, including a change in the HPF (high-pass filter) from 80 Hz to 135 Hz. There may be other changes that have not yet been identified.
The microphone can be powered by either phantom power or two 9V batteries. Unusually, phantom power is used to charge the two built-in rechargeable batteries rather than directly driving the microphone's amplifier circuitry. These batteries are capable of supplying the high current required by the output circuit's operational amplifiers at moments of high SPL (sound pressure level).
The capsule is a large diameter real capacitor, Neumann K67 series style. The outer diameter of the capsule is 33.6 mm and the suspended portion of the diaphragm is 26.3 mm.