LA-2A Leveling Amplifier

The LA-2A was invented by James F. Lawrence II, founder of the Teletronix Engineering Company in Pasadena, California in the early 1960s. The LA-2A had evolved from Lawrence's first leveling amplifier, the LA-1, which was favored by Gene Autry, and its successor, the LA-2, which had been adopted by CBS and RCA. In 1965, Lawrence sold Teletronix to Babcock Electronics of Costa Mesa, California, and in 1967 Bill Putnam's company Studio Electronics (eventually renamed UREI), acquired Babcock's broadcast division, including the Teletronix brand.{{cite web |last1=Fuston |first1=Lynn |title=A History of the Teletronix LA-2A Leveling Amplifier |url=https://www.uaudio.com/blog/la-2a-analog-obsession |website=Universal Audio }}

Three versions of the LA-2A were made until 1969.{{cite web|url=http://www.uaudio.com/_works/pdf/manuals/LA-2A_manual.pdf |title=LA-2A Manual |accessdate=2009-03-11 |url-status=dead |archiveurl=https://web.archive.org/web/20061113094825/http://www.uaudio.com/_works/pdf/manuals/LA-2A_manual.pdf |archivedate=2006-11-13 }}

After Universal Audio was re-established in 1999, the company re-issued an updated version of the LA-2A.{{cite web |last1=Cooper |first1=Michael |title=Universal Audio LA-2A |url=https://www.mixonline.com/technology/universal-audio-la-2a-370120 |website=Mix |date=November 2000 |publisher=Future Plc |access-date=10 September 2021}}

The LA-2A was inducted into the TECnology Hall of Fame in 2004.{{Cite web |last=Petersen|first=George|url=https://www.mixonline.com/technology/tecnology-hall-fame-1877-1950-380557|title=TECnology Hall of Fame, 1877-1950: 25 Audio Innovations That Changed The (Pro Audio) World|website=mixonline.com|publisher=Future Plc|date=1 September 2004|access-date=26 October 2021}}

The LA-2A is a hand-wired, tube-based compressor. It uses an electroluminescent panel together with a cadmium-sulfide light-dependent resistor (which in the LA-2A's own terminology is called the T4 cell) to provide gain reduction. The properties of the T4 give the LA-2A its unique character by making it an entirely program-dependent design.

The LA-2A has simple controls: a Peak-Reduction knob controls the gain of the side-chain circuit, and therefore, the gain reduction; a Gain Control for make-up gain; and a Limit/Compress switch which alters the compression ratio. The VU meter may also be switched to show the gain reduction or output level.

The average attack time is 10 milliseconds,{{Cite web|url=https://www.uaudio.com/webzine/2003/june/text/content4.html|title=Universal Audio WebZine: Compression Obsession: The Amazing Release Character of the LA-2A|website=uaudio.com|publisher=Universal Audio|date=June 2003|access-date=26 October 2021}} while the release time is about 60 ms for 50% release and 0.5 to 5 seconds for full release, depending on the previous program material.JBL vintage service manuals. [http://www.jblproservice.com/pdf/Vintage%20JBL-UREI%20Electronics/UREI-LA-2A%20manual.pdf UREI LA-2A service manual.] "This Instruction Book was reprinted from text composed by the original manufacturer (complete with errors and exaggerations; for example, the specification for attack time should have been in milliseconds rather than microseconds." Retrieved on October 11, 2009.

The LA-2A has the ability to preserve the impression of performance dynamics while performing extreme level management—a sonic character that makes it sought after by many recording engineers,{{cite web |title=Top 20 Best Compressors of All Time |url=https://www.attackmagazine.com/reviews/the-best/top-20-best-hardware-compressors-ever-made/20/ |website=Attack Magazine |date=13 November 2012 |access-date=10 September 2021}} particularly for use on vocals and bass guitar.{{cite web|last=Senior|first=Mike|title=Classic Compressors: Choosing The Right Compressor For The Job|url=https://www.soundonsound.com/techniques/classic-compressors|website=soundonsound.com|publisher=Future Plc|date=September 2009|access-date=26 October 2021}}

Recording engineers who cite the LA-2A in their work include Joe Barresi, Mike Clink, and Tony Maserati. The LA-2A was used to record Alanis Morissette's vocals on Jagged Little Pill,{{cite web|last=Humberstone|first=Nigel|url=https://www.soundonsound.com/people/christopher-fogel-alanis-morissettes-jagged-little-pill|title=Christopher Fogel: Alanis Morissette's Jagged Little Pill|website=soundonsound.com|publisher=Future Plc|date=March 1997|access-date=26 October 2021}} Kurt Cobain's vocals on Nevermind,{{cite web|last=Zoppa|first=Matt|title=An Analysis of Nirvana's Nevermind|url=https://medium.com/@mattzoppa/an-analysis-of-nirvanas-nevermind-3f1afe624463|website=medium.com|publisher=Matt Zoppa|date=30 September 2019|access-date=26 October 2021}} and Shakira's vocals on "Hips Don't Lie".{{cite web|last=Tingen|first=Paul|title=Secrets Of The Mix Engineers: Serge Tsai - Inside Track - Shakira and Wyclef Jean: 'Hips Don't Lie'|url=https://www.soundonsound.com/techniques/secrets-mix-engineers-serge-tsai|website=soundonsound.com|publisher=Future Plc|date=June 2007|access-date=26 October 2021}} Joe Chiccarelli used an LA-2A to add distortion to Jack White's vocals on The White Stripes' album, Icky Thump.

{{Quotation|LA-2As warm things up. ...they EQ all the warmth and low mids and bass. When you put bass and drums in them they get fatter and bigger. And unless you hit them way hard and make the tubes sizzle they don't really distort.|Jim Scott}}

Universal Audio has offered an officially-branded Teletronix LA-2A software plug-in since 2002, when they included the first version with their UAD-1 PCI DSP card.{{cite web|last=James|first=Rob|title=Review: Universal Audio UAD-1|url=https://www.resolutionmag.com/wp-content/uploads/2016/03/Universal-Audio-UAD-1-1.pdf|website=resolutionmag.com|publisher=resolution|date=October 2002|access-date=26 October 2021}} An updated version was introduced in 2013, when UA released the LA-2A Classic Leveler Collection for their UAD-2 platform, which included three different versions of LA-2A: the late-'60s 'Silver' version, the mid-'60s 'Gray' version, and the early-'60s LA-2.{{cite web|title=Universal Audio LA-2A Classic Leveler Collection Review|url=http://www.musictech.net/reviews/universal-audio-la-2a-classic-leveler-collection-review/|website=musictech.net|publisher=MusicTech|date=15 May 2013|access-date=26 October 2021}}

Bomb Factory Digital released an emulation of the LA-2 as part of their Classic Compressors for Pro Tools plug-in bundle.{{cite web|last=Rudolph|first=Barry|title=Bomb Factory Digital: "Classic Compressors" Plug-ins For Pro Tools|url=https://www.mixonline.com/recording/bomb-factory-digital-classic-compressors-plug-ins-pro-tools-373374|website=mixonline.com|publisher=Future Plc|date=1 April 2000|access-date=26 October 2021}} This plug-in has since been re-branded as the Avid BF-2A.{{cite web|last=Cooper|first=Dan|title=Our List Of Top LA-2A Compressor Plug-in Emulations & Recreations You Should Try In Your Next Mix|url=https://www.pro-tools-expert.com/production-expert-1/2018/8/14/our-list-of-top-la-2a-compressor-plug-in-emulations-recreations-you-should-try-in-your-next-mix|website=pro-tools-expert.com|publisher=Production Expert|date=26 October 2018|access-date=26 October 2021}}

Waves Audio released a software plug-in emulation of the Teletronix LA-2A with Chris Lord-Alge's personal presets as the CLA-2A Compressor/Limiter plug-in.{{cite web|last=Stanfield|first=Geoff|title=Waves: CLA-2A & CLA-76 compressor/limiter plug-ins|url=http://tapeop.com/reviews/gear/106/cla-2a-cla-76-compressorlimiter-plug-ins/|website=tapeop.com|publisher=Tape Op|date=March 2015|access-date=26 October 2021}}

Other software versions of the LA-2A include the Cakewalk CA-2A, IK Multimedia T-RackS White 2A, and the Native Instruments VC 2A by Softube.

• UREI
• The 1176 Peak Limiter, another popular vintage compressor descended from the LA-2A
• The Empirical Labs Distressor, a modern compressor inspired partly by the LA-2A

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Category:Dynamics processing

Category:Effects units