The Telefunken R-F-T AR-70 Stereo Omni Directional Cardioid Condenser Tube Microphone is an advanced stereo version of the popular AR-51 tube condenser microphone. The AR-70 STEREO is an advanced stereo version of the popular AR-51 tube condenser microphone. It features a matched pair of large diaphragm dual sided TK51D capsules, a New Old Stock (NOS) ECC81 vacuum tube and a matched pair of German built Haufe T14/1 output transformers that are the same transformers found in ELA M 250/251, C12 and R-F-T AR-51microphones.

The AR-70 STEREO includes one fixed cardioid capsule on the bottom and on top, a capsule wired for remote multi-polar pattern capabilities. This allows the microphone to perform multiple stereo recording techniques, as well as a standard single channel monophonic recording, all in one package. In stereo mode, the AR-70 STEREO can be set up in a standard x/Y configuration, with each capsule orientated 90 degrees away from each other, resulting in a perfectly co-incidental pair. With the option of the multi-pattern functionality of the top capsule, the microphone can also be used in Mid-Side (M/S) technique, where the lower capsule is fixed in cardioid and the upper capsule is rotated 90 degrees and set to the Figure 8 polar pattern.

One of the most unique ways to use the AR-70 STEREO is in 'dual mono' mode, which can lead to all kinds of interesting textures for vocals. By running the outputs into two different microphone pre-amplifiers, the user can now have one capsule set up to sound its best on quieter passages in a vocal and the other for louder passages. If the user runs about 10dB more gain on the microphone pre-amplifier for the capsule that is set up to record quiet passages, t