Universal Audio Bock 251 Large Diaphragm Tube Mic

Universal Audio Bock 251 Large Diaphragm Tube Mic



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Handcrafted at the UA Custom Shop in California, with enhancements by world-renowned mic designer David Bock, this premium multi-pattern studio mic combines modern features with boutique craftsmanship, for years of impeccable recordings.

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The UA Bock 251 is a professional large-diaphragm tube condenser microphone featuring selectable polar patterns, an oversized transformer for extended low-frequency response, and premium hand-sourced components.

The UA Bock 251 is Universal Audio’s flagship multi-pattern tube condenser microphone, handbuilt at the UA Custom Shop in Santa Cruz.

Going beyond the famed ELAM 251, considered by many to be the greatest vocal mic ever made, this David Bock-designed masterpiece features hand-sourced components for rich vintage sound with enhancements for performance and consistency.

Key Features

Large-diaphragm tube studio condenser mic, lovingly handmade at the UA Custom Shop in Santa Cruz, California
Iconic, “golden unit” mic sounds with modern enhancements by David Bock
Switchable omnidirectional, cardioid, and figure-8 polar patterns
German-made CK12 capsule and Cinemag transformer

Add Handmade Magic to your Studio

The UA Bock 251 is David Bock’s loving interpretation of the classic 251 microphones he studied and maintained as chief technical engineer of the world’s top recording studios for two decades. Hand built at UA’s Custom Shop in Santa Cruz, California, the UA Bock 251 mic puts “golden unit” sound at the heart of your recordings.

Rich Tube Mic Sounds, with Updated Sonics

With its German-made CK12 capsule and large output transformer, the UA Bock 251 gives you extended low-frequency response down to 10 Hz and higher SPL capabilities versus vintage 251 microphones.

Built for a Lifetime of Harmonious Recording

Handwired using premium components, each UA Bock 251 is built and tested to David Bock’s exacting specifications. With its vintage-inspired case, robust shock mount and accessories, this mic spares no expense to last a lifetime.


  • POLAR PATTERN Switchable Omnidirectional, Cardiold, and rigure-8
  • CAPSULE Giameter Dual asymmetrical backplate Dual diaphragm CK12 type
  • TUBE New Old Stock ECC85
  • MAXIMUM SPL 118 dB SPL, 1% THD
  • ADJUSTABLE CONTROLS Polar pattern selector
  • FREQUENCY RANGE 10 Hz – 18 kHz +/-2 dB
  • SENSITIVITY -34 dB (19 mV) ref 1V at 1 Pa, 1 kHz
  • POWER UA Bock 251 PSU true linear, 115V (default) or 230V operation
  • CONNECTORS Tuchel (mic). 3-Pin XLR (power supply)

Additional information

Weight 1 lbs


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