Universal Audio Bock 251 Large-diaphragm Tube Condenser Microphone

Universal Audio Bock 251 Large-diaphragm Tube Condenser Microphone


Universal Audio Bock 251 Large-diaphragm Tube Condenser Microphone.

Resurrecting the legendary ELAM 251, considered one of the greatest vocal mics ever, the Bock 251 from Universal Audio is a flagship large-diaphragm tube condenser microphone that delivers exceptional sonic quality to your studio recordings, thanks to its extended frequency response and premium, handwired components. Sporting a NOS ECC85 vacuum tube, Cinemag transformer, and a German-made CK12 capsule, this surprisingly versatile studio mic provides the smooth, open tone of the original with modern enhancements for long-lasting reliability.

An onboard switch allows selection between cardioid, figure-8, and omnidirectional polar patterns, and the high max SPL of 118 dB allows you to use the Bock 251 on sound sources that vintage 251s would balk at. Engineered for a lifetime of exquisite recording, the Bock 251 comes with a dedicated external power supply, a shockmount, and a premium, vintage-style suitcase for convenient storage and transport.The Universal Audio Bock 251 is David Bock’s take on the vintage large-diaphragm tube condenser that is considered by legions of audio professionals to be the best-sounding microphone ever made. But how do you improve on perfection? The manufacturing processes of the 1950s and ’60s didn’t have the precision tolerances today’s products benefit from. Thus, no two vintage microphones sounded identical when fresh off the assembly line, much less after decades of (ab)use. The UA Bock 251 mic is a meticulous re-creation of a primo original unit, secured after an exhaustive worldwide search. Bock’s creation, however, is no mere clone.The Bock 251 boasts an upgraded structural design and state-of-the-art replica components for consistent performance and rock-solid reliability.

Like the original, it sports switchable cardioid, omnidirectional, and figure-8 polar patterns, but its custom transformer has been engineered to deliver extended frequency response and more generous headroom. Complete with a beefy external power supply, a connecting cable, a shockmount, a signature wooden storage box, and a vintage-style suitcase, the Universal Audio Bock 251 is an ultra-premium microphone that works wonders on vocals and instruments of all types. It will surely be the crown jewel of your mic locker.


  • 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
  • Frequency Response: 10 Hz - 18 kHz, ± 2 dB
  • Max SPL: 118 dB SPL, 1% THD 
  • NOS ECC85 tube
  • Requires included UA Bock 251 PSU true linear power supply
  • Premium vintage-style suitcase


  • Microphone Type -  Tube Condenser
  • Polar Pattern -  Multi-pattern
  • Frequency Range -  10 Hz - 18 kHz, ± 2dB
  • Sensitivity -  -34 dB (19 mV) ref 1V at 1 Pa, 1 kHz
  • Max SPL -  118 dB SPL, 1% THD
  • Output Impedance -  150 Ohms
  • Recommended Load Impedance -  Greater than 1.2K Ohms
  • Adjustable Controls -  Polar pattern selector for Cardioid, Omni, Figure-8
  • Connector -  Tuchel (mic), 3-Pin XLR (power supply)
  • Included Accessory
    • UA Bock 251 power supply, 100V, 115V (default), or 230V operation
    • Premium vintage-style suitcase
  • Dimensions -  8.5” (216 mm) length, 2” (52 mm) diameter
  • Weight -  1.58 lbs (716 g)