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Neumann U47 fet Collectors Edition

Cardioid Condenser Microphone

The U 47 fet, also known as the fet 47, was originally manufactured by Neumann from 1969 through 1986, and remained in inventory through 1989. The mic was re-released as a “Collector’s Edition” at the AES convention in Los Angeles in October, 2014.

According to Neumann staff, the Collector’s Edition is not a limited edition or limited production run. The microphone is part of the company’s product line for as long as it continues to sell.

Jürgen Breitlow, director of Research and Development for Neumann, says the original U47 FET went through six circuit revisions during its lifetime. The 2014 re-release uses the most recent, 1986-era version of the schematic.

Breitlow says that the mic’s circuit is built with components that match the performance of the originals. The transformer has been recreated based on the original blueprints. Part of the microphone’s circuit is laid out on a circuit board that matches the vintage model; part is built in point-to-point fashion, again matching the original.

Fet 47 circuit photo credit: Klaus Heyne, © 2014

An analysis by vintage mic expert Klaus Heyne shows how faithful the reissue is to a vintage specimen (see sidebar link to Klaus’ forum).

The microphone’s K47 capsule has been in continuous production for most of the history of the company; it is a 34mm O.D. capsule with a single brass backplate and two diaphragms made of 6-micron Mylar. The front diaphragm is center-terminated. The rear diaphragm is presumably clear Mylar (not metallized, nor terminated).

According to Martin Schneider, the K47 capsule produces a supercardioid pattern at 1kHz and above; this means it has a narrow lobe of sensitivity directly behind the capsule, with nulls at ±135°. (see the K47 page for more information). For this reason, the original Fet 47 was specified as having a supercardioid polar pattern. The reissue produces the same pattern, but is presented as a Cardioid mic, presumably for the sake of avoiding customer confusion.

Two switches on the rear of the microphone independently enable a high-pass filter (140Hz) and a 10dB pad. A third switch, located on the bottom of the microphone body, enables the mic output to be lowered by 6dB to prevent preamp overload. This 6dB pad switch will not prevent the mic’s circuit from overloading, but rather simply drops the output level of the microphone.

The new Fet 47 is hand-built and hand-soldered by Neumann/Sennheiser employees at the company’s plant in Wennebostel, Germany, using through-hole components.

The microphone has a built-in swivel arm that serves as a hard mount. It ships in a wooden storage case with a numbered certificate of authenticity.

The serial numbers for the Collector’s Edition begin at 10,000, which is approximately where the final production run in 1986 had ended. The new model can also be distinguished by the orientation of its Cardioid symbol, which has its null point toward the mic’s XLR jack, and by the length of the female threaded stand adapter, which is shorter on the reissue than on at least some of the original production microphones.

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The mic was released in 2014.

Specifications

Frequency Response - CardioidClick Graph to Compare!

Pickup Patterns	Pads & Filters
Cardioid (8 mV/Pa; 40 - 16,000 Hz)	Pad: -10dB (Via Switch) Pad: -6dB on output (Via Switch) Filter: HPF @ 140Hz (Via Switch)

Capsule Dimensions	Impedance	SPL/Noise
Capsule diameter: 34mm Diaphragm gauge: 6 microns	150 Ohms (Low)	Max SPL: 147 dB Self-noise: 18.0 dB(A)

Weight	Length	Max Diameter	Interface(s)
710g (25.04oz)	160mm (6.30'')	63mm (2.48'')	3-pin XLR male (1)

Power Specifications
Requires phantom power Phantom voltage: 48v

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