Shure RPM181/PRE

The RPM181/PRE Replacement XLR Preamplifier by Shure is designed to work in combination with one of four interchangeable capsules for the Shure Beta 181 side-address instrument microphone. The capsules come in cardioid, supercardioid, omnidirectional and bidirectional polar patterns making a highly versatile pair.

With a capsule attached, it weighs only 5.1 oz and gets close to any source even in the tightest conditions. Its wide frequency response and high SPL handling is great for miking dual sound sources such as between toms or acoustic instruments. It is also very useful as a mono drum overhead or pair two to create the Blumlein stereo effect.
The RPM181/PRE matched with any of the available capsules performs with little to no crossover distortion and provides exceptional low-frequency reproduction. The pair provides exceptional audio with consistent, textbook-like polar responses resulting in a mic with noteworthy sound and versatility.
Works with one of four interchangeable capsules for the Shure Beta 181 instrument microphone
The cardioid, supercardioid, omnidirectional and bidirectional capsules make this mic highly versatile
Weighs only 5.1 oz with attached capsule and captures any source even in the tightest conditions
Matched with any available capsule it performs with little to no crossover distortion and provides exceptional low-frequency reproduction

Type Condenser
Frequency Response 20 to 20,000 Hz
Polar Pattern 181/C: Cardioid
181/S: Supercardioid
181/O: Omnidirectional
181/BI: Bidirectional
Sensitivity Cardioid: -46.5 dBV/Pa[1] (2.4 mV)
Supercardioid: -49.5 dBV/Pa[1] (2.5 mV)
Omnidirectional: -52.0 dBV/Pa[1] (2.6 mV)
Bidirectional: -51.0 dBV/Pa[1] (2.6 mV)
Output Impedance 110 ohms (at 1 kHz)
Signal to Noise Ratio Cardioid: 73.5 dB
Supercardioid: 71.5 dB
Omnidirectional: 70.5 dB
Bidirectional: 71.0 dB
Self Noise Cardioid: 20.5 dB SPL-A
Supercardioid: 22.5 dB SPL-A
Omnidirectional: 23.5 dB SPL-A
Bidirectional: 23.0 dB SPL-A
Common Mode Rejection ?55 dB
Polarity Positive pressure on diaphragm produces positive voltage on pin 2 with respect to pin 3
Power Requirements 11-52 V DC[4] phantom power (IEC-61938) 2.4 mA, maximum
Maximum SPL 1000 Ohm Load
Cardioid: 149.0 dB SPL
Supercardioid: 152.0 dB SPL
Omnidirectional: 154.0 dB SPL
Bidirectional: 153.5 dB SPL

2500 Ohm Load
Cardioid: 151.5 dB SPL
Supercardioid: 154.5 dB SPL
Omnidirectional: 157.0 dB SPL
Bidirectional: 156.0 dB SPL
Dynamic Range 1000 Ohm Load
Cardioid: 128.5 dB
Supercardioid: 129.5 dB
Omnidirectional: 130.5 dB
Bidirectional: 130.5 dB

2500 Ohm Load
Cardioid: 131.0 dB
Supercardioid: 132.0 dB
Omnidirectional: 133.5 dB
Bidirectional: 133.0 dB
Clipping Level 1000 Ohm Load
7.5 dBV

2500 Ohm Load
10.5 dBV
Weight 5.1 oz (145 grams)