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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


Choose Your Bock Microphone

Bock 187

FET Condenser

Bock 167

Tube Condenser

Bock 251

Tube Condenser

Polar Pattern

Cardioid

Polar Pattern

Continuously variable Omnidirectional through Cardioid and Figure-8

Polar Pattern

Switchable Omnidirectional, Cardioid, and Figure-8

Capsule

1” diameter
Dual symmetrical backplate
Dual diaphragm K67 type

Capsule

1” diameter
Dual symmetrical backplate
Dual diaphragm K67 type

Capsule

1” diameter
Dual asymmetrical backplate
Dual diaphragm CK12 type

Tube

--

Tube

New Old Stock EF732

Tube

New Old Stock ECC85

Maximum SPL

125 dB SPL, 1% THD

Maximum SPL

118 dB SPL, 1% THD

Maximum SPL

118 dB SPL, 1% THD

Adjustable
Controls

PAD (-10 dB): Off/On
MODE: Fat/Normal
LOCUT: Off/On

Adjustable
Controls

PAD (-10 dB): Off/On
MODE: Fat/Normal
Hi FREQ: Cut 5 kHz, Cut/Boost 10 kHz, Flat

Adjustable
Controls

Polar pattern selector

Frequency
Range

20 Hz - 16 kHz +/- 2 dB

Frequency
Range

10 Hz - 18 kHz +/- 2 dB

Frequency
Range

10 Hz - 18 kHz +/- 2 dB

Sensitivity

-42 dB (8 mV) ref 1V at 1 Pa, 1 kHz

Sensitivity

-29 dB (33 mV) ref 1V at 1 Pa, 1 kHz

Sensitivity

-34 dB (19 mV) ref 1V at 1 Pa, 1 kHz

Output
Impedance

200 Ohms

Output
Impedance

200 Ohms

Output
Impedance

150 Ohms

Recommended
Load
Impedance

> 2K Ohms

Recommended
Load
Impedance

> 2K Ohms

Recommended
Load
Impedance

> 1.2K Ohms

Dynamic
Range

113dB

Dynamic
Range

99 dB

Dynamic
Range

100 dB

Signal-to-Noise Ratio

82 dB

Signal-to-Noise Ratio

75 dB

Signal-to-Noise Ratio

76 dB

Power

Phantom Power
48 VDC, 0.5 mA typical

Power

UA Bock 167 PSU true linear, 115V (default) or 230V operation

Power

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

Connectors

3-Pin XLRM

Connectors

6-Pin XLR (mic), 3-Pin XLRM (power supply)

Connectors

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

*The UA Bock 251 product is not affiliated with, sponsored, nor endorsed by any other company. The "251" name is used solely to identify the classic mic design that Universal Audio's product is based on. All other trademarks are property of their respective owners.

Customer Reviews

UA Bock 251

Overall Rating

5/5
(1)

M. Wertz

October 12, 2023

Great low end

Fabulous mic, incredible low end. A welcome addition to Little Cheddar Studios!