Heiserman Audio H251 Microphone
The Heiserman H251 is the newest model in the Heiserman lineup. Every aspect of the engineering of this new historical recreation was approached with great care. Equipped with the incredible Generation-4 Heiserman Hk12 capsule, it uses the same brass and acrylic chambered backplates and rich 6µm gold sputtered DuPont Mylar® found in its original. The Hk12 capsule, along with all hardware for the unit, is machined by hand in North Carolina by two master machinists.
Internally, every detail of the original 251 is meticulously recreated. From the production of the T14/1 transformer (engineered from a pristine 1961 vintage unit) to the acrylic circuit board, the full acrylic head assembly, and the original rotational pattern switch. The microphone’s circuit components include Vishay and Takman Rex resistors, NOS polystyrene and PIO capacitors, and a true-to-original wet Tantalum output capacitor. Completing the design is an automotive-grade painted finish in the original Siemens Grey color.
Each Heiserman H251 microphone system ships with a custom bulletproof power supply with world-switching capability, a 7.5 meter Sommer tube mic cable with a custom 251-style connector, and a rugged flight case. The “E” version of the microphone uses a 6072 vacuum tube, and the H251 is equipped with a TAD Premium Highgrade tube. Each microphone comes with a 3-year limited warranty.
Specifications:
- Length: 216mm
- Diameter: 50mm
- Polar Pattern: Cardioid, Omni, Figure-8
- Capsule: Generation 4 Hk12 Brass and Acrylic Chambered
- Tube: 6072 TAD Highgrade
- Transformer: T14/1
- Sensitivity: 17mV/Pa ± 1dB
- THD @ 1kHz @ 1Pa: <0.3%
- Impedance: 200 ohms / 50 Ohms (switchable via jumper links)
- Frequency Range: 20 Hz – 20 kHz
- Max SPL: 130 dB
- Self Noise: 10dBA
