CMC 6 U RFI Shield Microphone Amplifier

The CMC 6 is Schoeps’ most popular amplifier. 
Its electrical properties have set new standards in terms of low distortion levels and common mode rejection (i.e. suppression of interference induced in the microphone cable).

• flat frequency response
• very low harmonic distortion and noise
• works with 12V and 48V phantom power
• balanced, low-impedance output
• high suppression of interference on the microphone cable
• excellent protection against high-frequency radio interference with "RFI Shield"
• frequency-independent impedance
• signal transmission possible over very long cables
• reliable operation even with weak phantom power
• symmetrical, transformer- and capacitor-free output stage with a class-A amplifier
• above 20 kHz, the signal is attenuated for protection against interference in the ultrasonic range, e.g. through the ultrasonic autofocus of a film camera

The capsules of condenser microphones can't be connected directly to microphone cables or inputs; a microphone amplifier is required in between. Thus a complete microphone of the Colette series comprises any of the twenty available types of capsules combined with an amplifier. The CMC 6 U is designed for standard 48- and 12-Volt phantom powering. Its circuitry recognizes the supply voltage and adjusts itself automatically. Its performance characteristics remain essentially the same either way; mainly, the difference is that the current drawn at 12 Volts is greater than at 48 Volts. However, the 12-Volt mode consumes less power and might be preferred for battery-powered recording.

The microphone amplifier is responsible for providing the necessary electric charge to the capsule, without which it would be unable to generate a signal. Since the capsule's output signal is very weak (Hi-Z), it must be amplified. In order for the microphone's output to cleanly reach the next stage in the signal chain, it must undergo balancing and impedance matching before transmission. The CMC 6 incorporates a balanced, direct-coupled class-A amplifier, yielding a low output impedance, high RF shielding, and minimal distortion.