A Truly Authentic LA-3A In 500 Series Format
The classic Urei LA-3A has long been on AudioScape's list to tackle. As no fans of the original’s half-rack format, they set about the challenging task of designing a PCB that would fit inside a single-space 500 series unit zero compromise to the core LA-3A circuit.
It took a lot of R&D and many revisions, but they finally pulled it off: an LA-3A with the same transformer mojo, 1970s components, and an authentic Teletronix-style T4B opto cell as the original, adapted to a modern format and priced within reach of the working engineer.
Recreating the Iconic LA-3A Compressor: The All-Important T4B Cell
The Urei LA-3A, like its more famous tube-based predecessor (the Teletronix LA-2A), utilized a T4B opto-attenuator for gain reduction. This is by far the most important thing to get right when recreating these legendary opto designs. Like the AudioScape Opto Comp, the V3A uses their made-in-house T4B cells, built to the exact spec as Teletronix originals - simply because no other alternative on the market is manufactured this way. To AudioScape, it’s a no-brainer that if you want the sound of the original, you should build it like the original however you can. Especially the opto cell!
AudioScape meticulously tests and sorts every T4B cell they make, since the electroluminescent panels naturally vary in response and performance. AudioScape has found that the faster cells more closely nail the behavior of the late 60s-1970s T4Bs as found in original LA-3A units, so they use these in the AudioScape V3A compressors, and reserve the slower cells for their LA-2A-style Opto Comp.
Nailing The Famous LA-3A “Mid-Push”
The LA-3A is famous for its ability to push sources boldly to the front of a mix, particularly those that benefit from a strong low mid. The behavior of the T4B cell when implemented in a solid-state circuit is notably different from its tube-based predecessor, the LA-2A, and the resulting compressor - a favorite of engineers like Tchad Blake and Bob Clearmountain - is famously outstanding on electric guitars, and extremely underrated as a vocal compressor.
Vintage NOS Components = Vintage Tone
Critical to nailing the tone and behavior of this 1970s design is the use of period-correct components. So, being the obsessive parts nerds AudioScape is, they hunted down the same 1970s metal can transistors and carbon film resistors that can be found in original units.
Precise, Custom-Wound Replica Iron
To nail the unit’s famously mid-focused “box tone,” AudioScape also designed precise, custom-wound replicas of the original 1960s and 70s-spec transformers and auto-former, including the crucial B11148 output transformer also used in the 1176 Rev F. Off-the-shelf replacements just don’t cut it here, and AudioScape took great pains in ensuring these transformers imparted the same magic to guitars and vocals as the original units.
It’s not for no reason that AudioScape has had many customers tell them they sold off their Urei or Teletronix-badged originals shortly after picking up a V3A (or two) - and they’d be silly not to, considering the crazy resale prices for vintage units!
Modern Updates & Upgrades
While AudioScape is sticklers for authenticity and vintage-style construction when it comes to tone, they also want these units to be easy to use in a modern studio! In adapting the LA-3A design to a 500 series format, they've made a few ergonomic changes - namely, moving previously rear-mounted switches and controls to the front panel. These include the “Stereo Link” button for chaining multiple units, plus “Limit/Compress” mode switching, a “Stereo Adjust” pot (used to balance both circuits’ gain reduction when linked) and the HF contour pot. This last control acts as a band-pass filter in the sidechain, making the DA-3A more responsive to high and high-mid frequencies the more it is turned.
The “Clearmountain” / Ed Evans Mod, Included Stock
As a final upgrade to this classic circuit design, AudioScape has included as standard a simple mod that raises the internal gain structure. Originally attributed to master mixer Bob Clearmountain but Ed Evans was the chief tech at Power Station who came up with the mod, this now-standard mod reduces the V3A’s already low noise floor even further, without otherwise impacting the unit’s sound or behavior.
