Universal Audio BOCK-251 Tube Condenser Microphone

Reach Sonic Nirvana
The UA Bock 251 is our flagship large-diaphragm tube condenser mic, giving you the smooth, open tone of the iconic ELAM 251,* considered by many to be the greatest vocal mic ever made. Each microphone is handmade in Santa Cruz, California, to the exacting specifications of world‑renowned mic designer David Bock.

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. Handbuilt 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.

• 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

Bock 251
Tube Condenser

POLAR PATTERN
Switchable Omnidirectional, Cardioid, and Figure-8

CAPSULE
1” diameter
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

OUTPUT
IMPEDANCE
150 Ohms

RECOMMENDED
LOAD
IMPEDANCE
> 1.2K Ohms

DYNAMIC
RANGE
100 dB

SIGNAL-TO-NOISE RATIO
76 dB

POWER
UA Bock 251 PSU true linear, 115V (default) or 230V operation

CONNECTORS
Tuchel (mic), 3-Pin XLR (power supply)