Search Microphones

Share This Page

Mods for the C 12

  • HamptoneHamptone
    Scott Hampton repairs vintage tube mics, especially those needing new power supplies. His mic repairs involve replacing and updating selected components, fine-tuning the circuitry, and restoration of the mic's original sonic character. He can also furnish a Hamptone second-generation Tube Mic Power Supply.
  • The Mic ShopThe Mic Shop
    Bill Bradley restores vintage mics in Nashville, TN.

9 polar patternsAKG Acoustics C 12

Multi-Pattern Tube Condenser Microphone

AKG’s C12 is one of the best-known tube condenser microphones in history. It is a side-address, large-diaphragm design based on AKG’s CK12 capsule, a 6072 dual-triode glass tube, and a transformer-coupled output circuit.

AKG C12 CircuitThe C12 is the evolutionary source of several other significant mics, such as AKG’s 414 series and Telefunken’s Ela M 250/251. Numerous modern manufacturers have released tribute/recreation models claiming at least some degree of historical accuracy (see the Related Mics sidebar).

The original CK12 capsule is widely considered to be one of the finest condenser microphone capsules in history. Although it evolved over time, as AKG changed diaphragm materials and weights (from 10-micron Styroflex to, eventually, 6-micron Mylar), and changed the size of the chamber between the backplates, the basic design remained the same: a dual-backplate large-diaphragm capsule with twin edge-terminated diaphragms.

AKG N12 power supply and S12 switch boxBy varying the voltage and polarization of the two diaphragms, the user could alter the microphone’s directionality. The C12 could produce 9 different polar patterns. Curiously, the switch was found neither on the microphone body nor the power supply, but on a separate device called the S12, which plugged into the N12 power supply via a dedicated cable.

AKG C12The AKG catalog boasted that the S12 could alter the mic’s polar pattern “without clicking or other disturbing noises [up]on switching,” and further that neither the mic’s sensitivity nor frequency response varied with the pattern.

The C12 shares a capsule, tube, and amplifier-circuit similarities with the Telefunken Ela M 251E, which was commissioned by Telefunken and built by AKG. But numerous differences between the two mics mean the two mics sound different:

  • The amplifier circuits are not identical.
  • Pattern controls on the 251 were on the microphone body.
  • The tube in the 251 was inverted, reducing the possibility of signal loss and noise by reducing the length of the cable connection to the capsule.
  • The 251 case and headbasket were ~9mm larger in diameter, and the grille construction was different; these physical differences alters the frequency response and coloration of the capsule.

C12 Output TransformersAccording to Saturn Sound, early C12s used a V2148 output transformer, which AKG soon replaced with a physically smaller design called the T14.

The C12 was discontinued in 1963, after a 10-year manufacturing run. Approximately 2500 C12 microphones were produced.

In 1994, AKG released the C 12 VR (Vintage Revival), presented as an “exact replica of the original C 12.” The mic uses a 6072 tube, and a capsule called a CK12, but has little else in common with the capsule, circuit, or sound of the original C12.

The AKG Acoustics C 12 is also known as: C12.

The mic was released in 1953.


Frequency Response - OmnidirectionalClick Graph to Compare!
C 12 Omnidirectional Frequency Response Chart
Frequency Response - CardioidClick Graph to Compare!
C 12 Cardioid Frequency Response Chart
Pickup Patterns Pads & Filters
Omnidirectional (10 mV/Pa; 30 - 15,000 Hz)
Cardioid (10 mV/Pa; 30 - 15,000 Hz)
Capsule Dimensions Impedance SPL/Noise
Diameter n/a
200 Ohms (Low)
Weight Length Max Diameter Interface(s)
560g (19.75oz) 255mm (10.04'') 43mm (1.69'')
  • 3-pin XLR male (1)
Power Specifications
  • Includes tube power supply

Did we get anything wrong on this page? Please let us know!