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The CAD equitek e3002
multi-pattern condenser microphone

The CAD e300-2


The CAD e300-2

The CAD equitek e300² combines a 1.1-inch 24K gold sputtered externally biased triple pattern (cardioid, omni, figure 8) dual diaphragm capsule with advanced elec­tronics. Typical FET (field effect transistor) condenser microphones use discrete designs. This means they use individual transistors that must be carefully matched for proper char­acteristics. Even with careful matching, discrete designs are in­herently non-linear. CAD equitek microphones use a different approach. We* do not use any discrete FETs. Instead, we use advanced high-speed OpAmps (Operational Amplifiers). These OpAmps are indi­vidually laser trimmed for optimum performance and have very high gain. This allows a large amount of negative feedback to be used to significantly reduce any non-linearity. During transients, these OpAmps may re­quire more current than typical phan­tom power supplies can deliver. The extra current demands are accommodated by our unique power supply design. Instead of using phantom power to operate the microphone, we use it to charge a pair of rechargeable batteries. This system provides a huge current reserve for the micro­phone’s electronics, yet there is no maintenance involved because the micro­phone automatically keeps the batteries charged during use. The use of OpAmps is not the only unique feature of equitek microphones. For example, we also supply servo cir­cuitry to minimize DC offset and eliminate interstage coupling capacitors. If using alkaline 9-volt batteries, do not apply phantom power to the microphone. Doing so could cause permanent damage to the microphone and void your warranty. NOTE: If you normally operate the microphone from phantom power, it is best to leave the micro­phone power switch in the ON position at all times. (The microphone auto­matically shuts off to conserve battery power when phantom power is removed.)
*The term “we” refers to the good folks at Conneaut Audio Devices.

The CAD e300-2


  • Generating Element: Externally polarized condenser

  • Polar Pattern: Cardioid, Omnidirectional, Figure 8

  • Frequency Response: 10 Hz–20 kHz

  • Sensitivity: −34 dBV (20 mV) at 1 Pa

  • Impedance: 200 ohms

  • Self Noise: 12 dB-A

  • Maximum SPL: 145 dB

  • Switches: Pad, hi-pass, polar pattern, on/off with auto shut-off option

  • Hi-pass: 135 Hz, 6 dB/octave

  • Pad: 20 dB

  • Powering Requirements: 48V phantom, 8 mA

  • Connector: Three-pin male XLR type

  • Finish: Durable black urethane. Brass-plated front screen

  • Net Weight: 2.3 pounds (1.0 Kg) with shock mount



Powering the equitek e300²
The CAD equitek e300² is powered by a combination of 48-volt phantom power and a pair of rechargeable 9-volt batteries. This powering arrangement overcomes the inherent current limiting associated with most phantom power supplies. The bat­teries are trickle-charged by the phantom supply. When needed, the batteries provide the extra current necessary during high SPL transients. The microphone will not function properly without the batteries present. The microphone can be used without phantom power for periods of up to six hours provided the batteries are fully charged. Standard 9-volt alkaline batteries can also be used if extended operation is needed when no phantom power is available (auto power shut off circuit must be disabled for battery operation without phantom power). The minimum require­ment for the phantom supply is a regulated 48 volts with the capability of supplying at least 8 mA of current. Supplies that do not meet this require­ment will not allow continuous operation of the microphone. Before initial use, the batteries may need to be fully charged. Once the batteries have received this initial charge they should not need to be charged in this manner again unless the microphone is unused for a long time. The batteries can be charged by two different means: 1. Connect the micro­phone to a phantom supply and allow the batteries to charge 12 to 14 hours with the mic turned off. 2. Remove the batteries from the microphone and charge them using a standard battery charger.

The CAD e300-2

Auto power shut off configuration
The following instructions are only important if you plan on using the e300² without a phantom power supply, such as for remote DAT recording. The equitek e300² in­cor­po­rates a circuit which shuts off the microphone if phantom power is removed. This is done so that battery power will be conserved if the user forgets to turn off the microphone. If it is desired to operate the microphone using only the batteries, this feature must be disabled or the microphone will not function. This is easily done by means of a small movable configuration jumper located inside the battery cover of the microphone. To access batteries and Auto Shut Off jumper: Remove the three screws on the bottom of the microphone with a #2 Phillips screwdriver. Carefully re­move the bottom plate so as not to break the three internal signal wires. Reverse this process for assembly. If you do not plan to use the microphone without phantom power, it is recommended that the con­fig­ura­tion jumper remain in its default ON position.

Auto Shut Off jumper
Auto Shut Off jumper

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A special note about batteries
The high-quality rechargeable batteries used in the equitek e300² are Nickel Metal Hydride or Nickel Cadmium type. They were selected to provide long life with virtu­ally no maintenance and have a number of properties that make them superior to most commonly available rechargeable 9-volt batteries: 1. Higher output voltage, 2. Lower self-discharge rate, 3. High immunity to overcharging. If the e300² is operated with a 48-volt phantom power supply, it is unlikely the batteries will ever need to be recharged even if the microphone is unused for months. If it should ever become necessary to replace the batteries, or if you simply want a spare set, use only high-quality Nickel Metal Hydride or Nickel Cadmium type batteries.


The high gain and wide bandwidth of the e300² microphone will easily overload the inputs of many professional audio mixing consoles if adequate precautions are not taken. This is especially true if the mic is going to be used on percussion or amplified electronic instru­ments. If you have never used this microphone before, we* strongly recommend that you initially reduce the system gain by doing one or more of the fol­lowing: 1. Enable the pad on the input of your console. 2. Start with the input trim control on your mixer adjusted to a low level. 3. Enable the −20 dB attenuator pad on the e300² microphone.
*The term “we” refers to the good folks at Conneaut Audio Devices.

e300-2 case

All photographs, illustrations, and text are courtesy of Conneaut Audio Devices.

Download the User Manual for this mic.



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