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ADK S-51

Pricing & Availability

  • MSRP: $299
  • Discontinued


Reviews & News

S-51 Documentation

CardioidADK S-51

Cardioid Condenser Microphone

The ADK S-51 Mk 5.2 is a side-address cardioid condenser with a large-diaphragm capsule and switchable pad and filter.

It is the next-generation A-51, a mic whose original design dates to 1998. The S-51 was originally known as the A-51 S, with the ‘S’ standing for ‘SPL.’ While the A-51 mics have always had internally switchable high-pass filters, the ‘S’ introduced a pad (-10dB) and external switches for both the pad and filter. The ‘S’ revision replaced the A-51 entirely within ADK’s product line, and was renamed the S-51.

Like the entire A-51 line, the S-51 combines a K67 capsule with a transformer-coupled circuit. We believe the mic uses a 2-stage FET amplifier in an “emitter follower” configuration, with a 2:1 output transformer, much like the MXL 2001/V67 (which were reportedly copied from the original A-51 Type II).

Recording Review, 2011

I’m buying four of these ADK S51 MK5.2s microphones. They will officially be my tom microphones, bass cabinet microphones, and serve general purposes where I need a little extra top end. I prefer my Gefell M930 or Neumann KM184 slightly on acoustic guitar depending on what I’m going for.

At $199, this thing provides a mostly neutral sound with a little bit of top end added. For a song that was more of an R&B-type thing I chose it over my Peluso 2247 short body, Peluso 251, and even the ADK TC-47AU even though all of those mics are badass.

The S-51 Mk5.2 ships with a wooden box and heavy-duty metal ring mount.

The ADK S-51 is also known as: A-51S, S51, S-51 Mk 5.2.

The mic was released in 2008.


Pickup Patterns Pads & Filters
Cardioid (15 mV/Pa)
  • Pad: -10dB (Via Switch)
  • Filter: HPF @ 100Hz (Via Switch)
Capsule Dimensions Impedance SPL/Noise
Diameter n/a
200 Ohms (Low) Max SPL: 140 dB
Self-noise: 17.0 dB(A)
Weight Length Max Diameter Interface(s)
n/a n/a n/a
  • 3-pin XLR male (1)
Power Specifications
  • Requires phantom power
  • Phantom voltage: 48±4v

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