Universal Audio UA Bock 251 Large-Diaphragm Tube Condenser Microphone

Put a flagship, hand-built tube microphone at the center of your studio with the Universal Audio UA Bock 251. Designed by David Bock and handmade at the UA Custom Shop in Santa Cruz, California, this large-diaphragm condenser pairs a German-made CK12 capsule with a Cinemag output transformer and a NOS ECC85 tube.

Switchable cardioid, omnidirectional, and figure-8 patterns support focused vocal tracking, room capture, ensemble recording, and classic stereo techniques. Its extended response reaches down to 10 Hz, while the included true-linear power supply and proprietary cable form a complete matched system.

Key Features

• Flagship large-diaphragm tube condenser microphone designed by David Bock
• Handmade and individually tested at the UA Custom Shop in Santa Cruz, California
• German-made CK12 capsule
• Cinemag output transformer and NOS ECC85 tube
• Switchable cardioid, omnidirectional, and figure-8 polar patterns
• Extended 10 Hz–18 kHz frequency response
• Complete system with matched power supply, shockmount, cable, wooden microphone box, and premium suitcase

Technical Specifications

• Microphone type: Large-diaphragm tube condenser
• Polar patterns: Cardioid, omnidirectional, figure-8
• Frequency response: 10 Hz–18 kHz, ±2 dB
• Maximum SPL: 118 dB SPL at 1% THD
• Sensitivity: 19 mV/Pa
• Output impedance: 200 ohms, transformer balanced
• Recommended load: 1.2 kohms
• Tube: NOS ECC85
• Capsule: German-made CK12
• Microphone dimensions: 8.5 in long × 2 in diameter
• Microphone weight: 1.58 lb / 716 g

What’s Included

• Universal Audio UA Bock 251 microphone
• Shockmount
• UA Bock 251 true-linear power supply
• 20 ft proprietary Tuchel cable
• Wooden microphone box
• Premium vintage-style suitcase

Setup note: Use only the included matched power supply and proprietary six-pin Tuchel cable. The microphone does not require phantom power. The UA badge marks the front address side. Standard manufacturer warranty is two years, with one-year coverage for the tube; retain the original invoice.