Advanced Audio Microphones CM47

Advanced Audio CM47

The Advanced Audio CM47 is a large dual-diaphragm, multi-pattern, tube condenser microphone inspired by the famous Neumann U-47. The CM47 is a great choice for vocals, saxophones, acoustic instruments, and excels in front of bass and guitar amps.

Maria Bobone featured using the CM47 on her beautiful vocal. You can also hear the CM54 being used on Portuguese guitar.

Capsule

The Advanced Audio CM47 features our very accurate and smooth AK67 capsule, a 35mm capsule with 6-micron-thick German mylar diaphragms. Its frequency response falls between those of the U47 and U67 vintage tube microphones.  The AK67 capsule goes down another ½ octave before rolling out, compared to the K47 capsule.  The CM47 also has more “air” or “sizzle” above 10kHz, allowing it to cut more easily through busy mixes without adding EQ.

Circuit

The circuit is based on the very hifi 6072 tube optimized with a two-stage Class A design. 

This circuit provides a much lower output impedance with more headroom than the circuit used in the original U47. The lower output impedance provides a faster damping factor when driving the BV8 type transformer, delivering a better transient response than the original design.

Selected 6072a tubes are some of the quietest tubes made, and are much less susceptible to microphonics than the metal-clad vf14 tubes used in the original U47 tube microphone.

The dual-bobbin output transformer with its hum bucking configuration and our optimized circuit will deliver +20dBu with less than 1% distortion.

The output transformer is driven with a 2.2 ufd metal-film capacitor to take advantage of the transformer’s response down to 10Hz.

Specifications:

• 1.07” (35mm) dual 6-micron German mylar diaphragm AK67 capsule
• 9 selectable pickup patterns remotely switched from the power supply
• Dual bobbin BV8 (6.5:1 ratio) output transformer
• 6072a tube Class A dual stage (CCDA)
• Frequency response: 25Hz to 20kHz +/–3dB
• Noise: -17dB (A-weighted)
• Impedance: < 200 ohm
• Distortion: < 0.5% @128dB
• Output: +20dBu with less than 1% distortion into 1.2K load
• Robust shock mount that threads onto microphone bod
• Flight case.