The ITP was discontinued in January 2015.

The ITP is a low-noise, transformer-coupled input, phantom- or battery-powered inline microphone amplifier. Intended for use with dynamic moving-coil and ribbon microphones, the ITP offers a variable gain range of +22dB to +42dB.  The ITP’s electrically balanced, low impedance output enables use of cables up to 300′ (100m) without signal degradation. The ITP’s gain is not affected by the load impedance of the connected preamp. The ITP also offers excellent common mode rejection and phantom power supply noise rejection. The ITP’s input transformer blocks phantom power from reaching connected microphones.

The ITP may include an internal A23 (12V) battery mount (battery not included). The ITP will operate either on phantom power or battery power, switching automatically to battery when phantom power is not present. The ITP’s LED indicates power status: red for phantom power and green for battery power.

For battery operation, an XLR cable with termination from shell to pin 1 must be connected to the input of the ITP. Most microphones have an internal pin 1 to case connection, so the ITP may be directly connected to the microphone to make the required pin 1 to shell connection. When this connection is made, the ITP will be switched on battery power if phantom is not present.  Note that while the ITP will run on phantom power with pin 1 to shell connection on the input, there will be no connection of the input pin 1 to ground, which will leave the cable and microphone unshielded. For this reason, if direct connection to the microphone or a shell-grounded cable is not possible, the ITP should be ordered without the battery option.

To access the ITP’s battery, remove the screws on the bottom side of each XLR connector (do not remove top screws), then remove the bottom panel (top panel has knob). Battery life is approximately 40 hours. Low battery (7V) is indicated by yellow color on LED.

ITP Specifications:

Type: inline phantom- or battery-powered microphone amplifier with transformer-coupled input

Phantom power: +12V to +48V (headroom reduced below +33V)
Battery power: +12V A23 battery
Current: 1.4mA

Input Impedance: 2kΩ
Output Impedance: 150Ω
Recommended Preamp Input Impedance: 1.5kΩ or higher

Gain Range: +22dB to +42dB

Maximum Input Level, 1kHz @ 1% THD, +48V phantom power: -4dBV
Maximum Input Level, 1kHz @ 1% THD, +12V battery or phantom power: -14dBV
Maximum Output Level, 1kHz @ 1% THD, +48V phantom power: +18dBV
Maximum Output Level, 1kHz @ 1% THD, +12V battery or phantom power: +8dBV
Total Harmonic Distortion, 1kHz @ 0dBV: 0.01%
Total Harmonic Distortion, 100Hz @ 0dBV: 0.1%

Frequency Response, 150Ω source: 30Hz to 20kHz
Equivalent Input Noise, maximum gain: -127dBV unweighted; -130dBA
Common Mode Rejection Ratio: 70dB minimum

Dimensions:  123mm L x 30mm H x 25mm W (4 7/8″ L x 1 1/8″ H x 1″ W)
Weight:  116g (4oz)