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The Heiserman H251 is a premium large-diaphragm valve microphone designed for professional studio recording, offering versatile polar patterns and meticulous vintage-inspired engineering.
Overview
Engineered with precision for demanding studio environments, the Heiserman H251 features the Generation 4 Hk12 capsule, constructed with brass and an acrylic-chambered backplate. The capsule utilises 6-micron gold-sputtered DuPont Mylar® to achieve superior transient response and sonic clarity. Two master machinists in North Carolina handcraft every component, ensuring exceptional consistency and mechanical precision.
Internal Design
The microphone incorporates a faithful recreation of the original 251 circuit, including an acrylic circuit board, full acrylic head assembly and the original rotational pattern switch for selecting cardioid, omnidirectional or figure-8 polar patterns. The head assembly houses the authentic Ck12 saddle with felt and foam damping for mechanical stability.
Electronic Components
The circuit employs high-spec Vishay and Takman Rex resistors, alongside NOS polystyrene and PIO capacitors, delivering consistent tonal performance. The output stage features a true-to-original wet Tantalum capacitor, enhancing harmonic detail and warmth.
Transformer and Tube
The T14/1 transformer, reverse-engineered from a pristine 1961 vintage unit, delivers balanced output with enhanced low-end response and smooth high frequencies. The microphone runs a 6072 TAD Premium Highgrade vacuum tube, providing low noise performance and classic valve character.
Construction and Finish
The Heiserman H251 features a robust metal body with an automotive-grade Siemens Grey painted finish for durability and aesthetic authenticity. The system ships with a custom bulletproof power supply with global voltage switching, a 7.5-metre Sommer tube microphone cable with a custom 251-style connector, and a rugged flight case for secure transport.
Performance
The microphone offers a sensitivity of 17mV/Pa ±1dB, a frequency response spanning 20 Hz to 20 kHz, and a maximum SPL handling of 130 dB. The self-noise measures just 10dBA, ensuring pristine recordings, while selectable impedance options of 200 ohms or 50 ohms provide flexibility for different recording chains.
- Large-diaphragm valve microphone with cardioid, omni and figure-8 patterns
- Generation 4 Hk12 brass and acrylic-chambered capsule with 6µm gold Mylar®
- T14/1 transformer based on a pristine 1961 vintage design
- 6072 TAD Premium Highgrade vacuum tube for low-noise performance
- Acrylic circuit board and head assembly with rotational pattern switch
- Premium components including Vishay resistors and wet Tantalum capacitor
- Automotive-grade Siemens Grey finish with bulletproof PSU and rugged flight case
- UK over £99 FREE
- UK under £99 £10
- EU £36
- Rest of World £80
Large/Heavy items: Extra charges may apply (e.g., consoles, large monitors). We’ll contact you before processing if so.
We ship with DPD and UPS across the UK, EU and worldwide. Same-day within the M25 is available depending on stock from £48.
At KMR, we provide exceptional support for all your audio studio requirements. Our committed team is ready to help you with setup, troubleshooting, and optimizing your gear for peak performance.
If you face any challenges, our customer service team is just a phone call away, prepared to offer expert assistance.