Microtech Gefell UM92.1 S

A Reference Tube Microphone, Carried by the Heritage of the M7 Capsule

The UM 92.1 S is part of the great tradition of studio tube microphones designed to deliver a rich and "large format" sound. At the heart of the microphone, the M7 capsule is selected for optimized polar response to maintain a stable image and natural balance regardless of the chosen polar pattern. This approach aims at a simple studio goal: to have a main microphone capable of immediately providing flattering body and presence without the need for excessive processing.

Who Is It For and What Are Its Studio Uses?

The Microtech Gefell UM 92.1 S targets demanding studios and home studios seeking a versatile tube condenser microphone, equally comfortable on intimate vocals as on more powerful takes. On vocals, it highlights a full low-midrange and smooth definition in the highs, with a typical tube circuit sense of depth. On solo instruments (brass, strings, acoustic guitar, amplifier), it helps capture a solid center and a "finished" image right from the recording.

The switchable polar pattern also opens the door to advanced recording techniques: figure-8 for face-to-face duets, Mid-Side recording (with a second cardioid mic), or better control of side reflections. In omnidirectional mode, you benefit from extended bass and a more natural room capture, ideal when the acoustics are well treated.

Features and Strengths: Polar Patterns, Tube, and Studio Integration

Polar Pattern Selection from the Power Supply: Real Daily Convenience

Polar pattern switching is done via a selector integrated into the UN 920.1 power supply. This is a tangible advantage in the studio: you adjust the polar pattern without handling the microphone, reducing handling noise and speeding up comparisons during a session. The on/off switch is also located on the front of the power supply for smooth use in a rack or on a studio desk.

An EF86 Tube Preamplifier Chosen for Its Sound Character

The UM 92.1 S features a tube preamplifier based on an EF86, a design renowned for its character and musicality. The tube is used in a proven architecture, with a focus on high sensitivity and a favorable signal-to-noise ratio for a tube microphone. The result: a recording that retains nuance in delicate passages while maintaining control when the source grows in intensity.

Designed for Real-World Setups: Cable Lengths and Connectivity

The UN 920.1 power supply delivers the polarization voltage required by the capsule as well as the DC voltages for the microphone electronics. For cable runs longer than 50 meters, the manufacturer recommends having the filament voltage adjusted by a technician to 5.8 V to maintain optimal operation over long distances. On the studio side, the rear of the power supply consolidates essentials: mains input with voltage selector, microphone output via 7-pin Tuchel connector, and audio output on a standard 3-pin XLR.

Finally, the microphone is offered in satin nickel or matte black, two discreet finishes that easily integrate into a professional microphone collection.

Technical specifications

Frequency response - start	40 Hz	Capsule	Large Diaphragm
Frequency response - end	18 kHz	Connection	XLR
Category	studio microphone	Color	Grey
Directivity	omnidirectional, cardioid, bidirectional

Type	tube condenser microphone	DC power supply voltage	120 V
Diaphragm	large gold-sputtered plastic	Anode current	1 mA
Tube	EF86	Filament voltage	5.8 V
Polar patterns	omni, cardioid, figure-8	Filament current	200 mA
Acoustic operating principle	pressure gradient transducer	Role	provides capsule polarization voltage and DC voltages for the microphone preamplifier
Frequency response	40 to 18,000 Hz	Mains voltage	115 V or 230 V
Sensitivity at 1 kHz	15 mV / Pa	Mains frequency	50 Hz or 60 Hz
Impedance	200 ohms	Front panel controls	polar pattern selector, on/off switch
Equivalent noise level (CCIR 468-4)	25 dB	Long cable recommendation	beyond 50 meters, have filament voltage adjusted by a technician to 5.8 V
Equivalent noise level (DIN EN 60651)	17 dB-A	Microphone output connector	7-pin Tuchel connector C 70/A
Signal-to-noise ratio (1 Pa at 1 kHz), CCIR weighted	69 dB	Power supply rear connectivity	mains connector with voltage selector, 7-pin Tuchel to microphone, standard 3-pin XLR (audio output)
Signal-to-noise ratio (1 Pa at 1 kHz), A-weighted	77 dB	Dimensions (L x Diameter)	197 mm x 42 mm
Maximum SPL for 0.5% THD	120 dB	Weight	430 g
Total dynamic range of microphone preamplifier	103 dB	Available finishes	satin nickel or matte black