Neumann U 47 FET
A solid-state answer to a tube legend — and the rare case where the sequel earned its own following.
Overview
The U 47 FET is what happened when Neumann took one of the most storied microphones in recording history and rebuilt it around a field-effect transistor instead of a valve. According to a contemporary review in Studio-Sound (November 1977, p.92), the FET version of the well-established U 47 was designed to offer lower noise and higher signal-handling capability than the original tube design. That's the pitch in one sentence: same capsule lineage, quieter floor, more headroom before things get ugly.
The capsule is the heart of the story. Neumann's own product lineage, as chronicled by EQ Magazine (August 1998, p.35) in its timeline of seventy years of Neumann microphones, places the U 47 FET among the company's landmark models — meaning the FET model carries the same capsule family that built the U 47's reputation. For anyone chasing that particular midrange character without the maintenance overhead of a tube, this is the point of the microphone. The trade press of the era treated the solid-state conversion as a straightforward improvement rather than a compromise; Recording-Engineer (April 1984, p.116) noted that the U 47 was prized by collectors for its high output, robust sound, and characteristically "up-front" properties.
The directional characteristic is cardioid, and the on-axis response is genuinely flat. Studio-Sound's (November 1977, p.92) bench measurements found the on-axis frequency response very flat, with the rear response becoming more critical — narrowly defined points where the high-frequency response shows a notch off the back. That's a cardioid behaving like a cardioid; the front is where the money is. The same review measured sensitivity at 1 kHz at 0.8 mV/µBar, matching Neumann's published figure, and put internal noise below 23 dB SPL A-weighted (or 30 dB CCIR-weighted referenced to 1 kHz). Spurious output from the internal DC-DC converter was measured at an extremely low level — under 3 µV below 200 kHz — which matters more than it sounds like it does when you're stacking a quiet source through a high-gain chain.
The switching is practical rather than fussy. A recessed high-pass filter reduces wind noise and unwanted low-frequency rumble, and two further recessed attenuator switches — operable with a pencil tip or small screwdriver — give a −10 dB step at the input to the preamp and a further 6 dB at the preamp's output, the latter specifically to avoid overloading downstream mixer inputs. Powering is 48V phantom, with the manufacturer's tolerance quoted at +6/−8V on the nominal supply, and the mic only draws 0.5 mA at nominal 48V — light enough that battery supplies independent of mains were a viable option. Connection is via the signal cable, with XLR or Tuchel connectors both available. Physically, it's a fairly bulky cylinder finished in a dull satin that Studio-Sound (November 1977, p.92) rated to a high standard and reasonably non-reflective for film and television work. Unusually, the mic has a built-in swivel arm for mounting to standard-thread stands, complete with a screw-type cable clamp to keep the cable clear of the body.
The U 47 FET also turns up in the historical record as a working tool rather than a museum piece. A 1977 Studio-Sound survey of roughly 250 studios (27 of which responded) listed the U 47 FET among the Neumann models in active rotation alongside the U 87, U 67, KM 84 and others — the U 87 dominated, but the FET was clearly part of the standard locker. A Mix (June 1991, p.128) equipment listing still had the U 47 FET on hire alongside U 87s and KM 84s, which tells you it stayed in service long after the tube original had become a collector's item. And in a 2015 Mix (February 2015, p.62) reissue comparison, an engineer reaching for a kick-drum sound found the U 47 FET completed the picture inside the drum alongside an AKG D112 — the kind of low-end work the mic has always been trusted with.
What the U 47 FET is not, at least in the surviving period documentation, is a microphone with a published list of weaknesses. The honest caveats are structural: it's a bulky body, the rear off-axis response has those high-frequency notches, and the recessed switches require a tool rather than a fingertip. Beyond that, the record here is thin on failure modes, current market pricing, and production dates — collectors chasing a specific serial range or a service history will need to look beyond what the period press preserved. What the documentation does support is a clear identity: the U 47 FET is the solid-state member of the U 47 family, built around the K47 capsule, measured flat on-axis, quiet in the noise floor, and flexible enough on attenuation and filtering to sit in front of loud sources without drama. For a microphone that exists in the shadow of a legend, that's a respectable place to stand.
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