Common name: Heiserman Audio H251
Production Status: In production
The H251 is an accurate recreation of the 251 large diaphragm tube condenser microphone. A 1961 vintage unit in perfect condition has been used to re-engineer the H251. The circuit is based around a 6072 TAD high grade tube and a Generation 4 Hk12 brass and acrylic chambered capsule using 6µm gold sputtered DuPont Mylar® diaphragms. The coupling transformer is a T14/1 type modeled from the vintage microphone. The acrylic circuit board and the full acrylic head assembly contains the original rotational pattern switch and full Ck12 saddle with felts and foam cushioning as in the original. Circuit components include Vishay and Takman Rex resistors, NOS polystyrene and PIO capacitors and the true to original design wet Tantalum output capacitor. Polar patterns can be switched between omni, cardioid and bidirectional. The H251 features an automotive grade painted finish using the original Siemens Grey color. Includes power supply with world switching, a 7.5 meter Sommer tube mic cable with custom 251 style connector and a flight case.