Black Lion Audio B172A Dual Compressor

1176-style FET compression or LA-2A-style opto compression? BLA's B172A has both sides of this dynamic duo, in separate circuits you can route any which way.

Every so often, two incredible things, wholly enjoyable on their own, combine to form a pair so sweet and complementary, that it becomes hard to think of one without the other... Sonny & Cher, Lennon & McCartney, Snoop Dogg & Dr Dre and perhaps the greatest and most literal "dynamic duo" of all time -- the 1176 and LA-2A!

Hear the B172A compressor on solo'd male vocals in this demo from BLA:

The 1176 and LA-2A, when used together, have become a studio stable for decades, often wired in series with each other so that one catches the audio's peaks and the other does the heavy compression. Black Lion Audio, having hit the mark with the widely adored Seventeen compressor, has struck again, combining the Seventeen's F.E.T. circuitry with a worthy optical section in the B172A! This unit combines the two separate '76 and 2A circuits into a single unit that allows you to route the signal in any order you like to be able to provide this very useful compression technique.

The Seventeen's success put pressure on BLA to pair the already proven F.E.T. side with an equally formidable optical mate. The challenge was met on the B172A through the creation of a custom T4B "opto" element called the "T4BLA". BLA's lengthy experience in modifications lent designers the proper patience and mindset to tweak subtleties in the optical element until it was a supreme asset in the design. With a heavy attention to detail and design, the T4BLA is designed to be the single best T4B optocell available read more today.

Flexibility was a main goal of the B172A since its initial concept. While many engineers agree on the benefits of using both compression types, the order in which to do so is still debated. The AB-BA switch on the B172A allows for quick internal routing of the signal. The two compressors can also be used completely independent of each other when utilizing the 3rd position (link off) on the AB-BA switch. Each circuit also has stereo linking so a pair of B172A's can be used in stereo.

As always, a painstaking amount of time has been spent on choosing the best possible transformers needed for the circuit. Featuring a Cinemag input transformer on the LA-2A side, BLA's own Chicago-wound output transformers on both circuits, high-grade signal path and decoupling capacitors, the B172A gives studio owners ultra convenient access to a pair of high quality dynamics processors that have stood the test of time while also providing a tool never before available in a single box.
WARNING: Cancer and Reproductive Harm -
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Dimensions and Weight in Packaging
Base Item
Shipping Weight: 17.5 lbs
Shipping Dimensions: 26 x 16 x 7 in
Manufacturer Part Number (MPN): B172A

For support or warranty questions, please contact the manufacturer:
Phone: 773-549-1885

Reviewers gave this product an overall rating of 5 out of 5 stars. (1 ratings)
Submitted December 4, 2022 by a customer from

"Learning Curveball"

Overall: 5 out of 5 stars
(see rating details)
Verified Customer zZounds has verified that this reviewer made a purchase from us.
OK, so... I've had my B172a for about 7 months now. It lives in my vocal chain. I bought it after about a year of using 76 and 2a plugins in sequence on just about every vocal. It just works, so when I saw thing thing, I was like, yup, send it here!I gotta admit, if I'd written this review when I first got this piece, it would not have gotten five stars. I hooked it up and let in burn in for, like, a day or so, and thought I'd be ready to rock'n'roll. Nope! It just didn't sound right, and I really couldn't get it dialed in. Also, the noise floor on the 76 side was stupidly high.Fast forward to now. After much trial and error, I have the gains and everything optimized for my setup and, guess what? At some point that hiss on the 76 side went away. I hadn't even noticed, it's been gone for a while. Maybe I should've let the thing burn in for three days out of the box. My last dozen or so recordings through this piece have been brilliant! So much so, I feel it's worthy of the full five stars, despite it being less than intuitive getting it going good initially. I wouldn't wanna work without it now.

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