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The large diaphragm, multi-pattern TELEFUNKEN AR-51 was created to bring the classic circuit of the ELA M 251E and C12 into a new, more affordable microphone. Featuring edge terminated TK51D capsule, a NOS (New Old Stock) ECC81 / 12AT7 vacuum tube and newly manufactured Haufe T14/1 output transformer, the AR-51 captures the same clarity as its predecessors and provides similar sonic characteristics, with its own unique distinctions.

Sonic Characteristic

In use, the AR-51 is a fantastic utility microphone. Its smooth mid-range, open top end, and solid, well-balanced low frequency translation make it a great choice on anything from vocals to drums and percussion to acoustic guitar to saxophone. With 9 variable polar patterns, the AR-51 has both versatility and superior accuracy in recreating your sound source as natural as it sounds.

Circuit Design

The AR-51 features the same amplifier electronics of the Austrian designed C12 and ELA M 251E microphones and pairs them with a dual sided, 26.5 mm large diaphragm TK51D capsule. At the core of the R-F-T AR-51 amplifier is a NOS ECC81 / 12AT7 vacuum tube, which is coupled with the same German built Haufe T14/1 output transformer found in the C12 and ELA M 251E.


The AR-51’s steel headgrille mesh and brass base ring are finished in black nickel plating, giving the microphone a unique look and vibe. The aluminum body tube is finished in a grey protective hard coat and is engraved with the microphone model name and serial number. An antique nickel plated TELEFUNKEN diamond logo badge is featured on the front of the microphone. The power supply is also finished in a black protective coating.


Each AR-51 microphone comes complete with M 901 power supply, M 801 25’ dual-shielded TX-7 tube microphone cable, M701 elastic shockmount and wooden microphone box.

Technical Specifications


Pressure Gradient Condenser


TK51D - 26.5 mm Edge Terminated Diaphragm

Tube Type



Haufe T14/1

Polar Pattern

9-Pattern Variable including Omnidirectional, Cardioid and Bidirectional

Frequency Range

20 Hz - 20 kHz, ± 3 dB


13 mV/Pa, ± 1 dB

THD at 1kHZ at 1Pa (Amplifier)

< 0.2%

Output Impedance

250 Ω

Maximum SPL (for 1% THD)

128 dB

S/N Ratio

86 dBA

Self Noise (Amplifier)



240 mm L x 46 mm Dia


769 g

Current Draw from Mains

50 mA

Power Supply

M 901 - 7 Pin Female XLR Input, 3 Pin Male XLR Output, Polar Pattern Selector


M 801 - 25 ft Accusound TX-7 Cable, 7 Pin Male & Female XLR's

Wooden Box


Flight Case

HC01 - Hard Shell Protective Case (not included), FC10S for Stereo Set

Video Gallery

Press Releases

AR-51 & AR-70 STEREO Vacuum Tube Updates

By Alan2 | June 21, 2017

Effective January 2017 the AR-51 and AR-70 STEREO microphones will ship with a new old stock National 12AT7WA vacuum tube, replacing the R-F-T ECC81 tube that was used from 2009 to 2014, and the GE ECC81 that was used from 2014 to the end of 2016. Originally made in England by the Mullard factory and…

Kenji Nakai Purchases Matched Pair of TELEFUNKEN AR-51s

By Alan | March 19, 2010

Large Diaphragm Tube Mics For Kenji Sano Solo Project Los Angeles, CA, June, 2010 – Before starting on the long-awaited Kenji Sano solo project, recording engineer Kenji Nakai purchased a matched pair of new TELEFUNKEN Elektroakustik AR-51 microphones.  Nakai, who came to the US in 1990 and has worked with such artists as the Red…