B172A Hybrid FET/Optical Compressor

B172A Hybrid FET/Optical Compressor


Double the classy in a single chassis, the B172A marries the Seventeen version of the legendary “76” FET limiter with our take on the renowned “2A” tube optical compressor. Whether you use the FET and opto separately — or in series, where one catches the audio’s peaks and the other provides the heavy compression — the B172A will blow you away with its incredible sound and versatility. The B172A’s Dual Mono Link makes it easy to route your signal through the 17 and 2A circuits in any order. Painstaking effort went into choosing the best transformers needed for each circuit. Spec’d with a CineMag input transformer on the 2A side, BLA’s own Chicago-wound output transformers on both circuits, high-grade signal path and decoupling capacitors, the B172A gives you ultra-convenient access to a pair of classic dynamics processors while also providing a valuable signal processing tool never before available in a single chassis.

SKU: b172a Category: Tags: , , , ,

• 76- (Seventeen) and 2A-style compression in a single 2RU chassis
• A/B, B/A, and Independent signal routing switchable on faceplate
• Cinemag 2A input transformer
• Chicago-wound 76 and 2A output transformers
• Custom-designed Black Lion Audio T4B opto element
• High-grade signal path and power decoupling capacitors
• Stereo linkable

Technical Specifications

Type: FET / Optical Compressor

Number of Channels: Stereo, Dual Mono Link

Controls: Ratio, Attack, Release, Peak Reduction

Ratio: 4:1 to 20:1

Inputs: 2 x XLR, 2 x 1/4″

Outputs: 2 x XLR, 2 x 1/4″

Other I/O: 2 x 1/4″ (link)

Additional Features: A/B or B/A signal routing

Rack Spaces: 2U

Power Source: Standard IEC AC cable

Width: 19″

Manufacturer Part Number: B172A

A note on the Attack and Release controls:

The Attack control on the B17A works a little differently than you may have encountered on other ‘76-style compressors. 

Turning the Attack knob to the left (counter-clockwise) will yield faster attack times; slower times result when turning to the right (clockwise). Turning the Release knob to the left (counter-clockwise) will yield faster release times; slower times result when turning to the right (clockwise). 

  • Attack: Continuously variable 20uS to 800uS
  • Release: Continuously variable 50mS to 1200mS


Additional information