Universal Audio WebZine
Volume 2, Number 9, October/November (AES) 2004
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Analog Obsession: Teletronix History Revealed, LA-2A Honored by TEC Hall of Fame, LA-610 Furthers Line, Precision Preamplifier Announced

I love it when the hand of fate brings several serendipitous events together to make for one great story. On the heels of Universal Audio's new release of the LA-610, which combines our 610 mic pre with the LA-2A's compression circuit, I gained contact with the family of the original LA-2A designer, Jim Lawrence. Gretchen Lawrence, Lawrence's widow, and his son-in-law Glen Macready shed new light on the history of Teletronix. At about the same time, Universal Audio was tapped on the shoulder by the Mix Foundation, informing us that the Teletronix LA-2A is included among twenty-four other inductees as historical/technical achievements under the new category of TECnology Hall of Fame. These inductees range from Thomas Edison's 1877 Cylinder Phonograph, to the introduction of Digidesign's Pro Tools in 1991- Viva synchronicity!

Mix Foundation TECnology Awards
The Mix Foundation will be hosting a public reception and awards ceremony for all twenty-five of the TECnology Hall of Fame inductees. The reception is scheduled for Friday, October 29th at 5:00 PM in the Moscone Center. The ceremony will be MC'd by none other than George Massenberg. Be there!

The Man Behind the Legend
James F. Lawrence Jr. was born June 24, 1924 in Hollywood, California. Jim served in the Navy during WWII, working as a radar operator. After his tour of duty, he began pursuing his Electrical Engineering degree from the University of Southern California. During his studies at USC, Lawrence also worked full time. He went to work for Parsons Electronics designing sub-miniature telemetry devices; but Lawrence's passion was always radio, so he took a job as a radio engineer at KMGM in Los Angeles. As a radio engineer, Lawrence became frustrated with having to ride gain to ensure a proper signal; it is there that he began to conceive of the idea of a "leveling amplifier".

"Jim Lawrence was a talented inventor and technological pioneer...his first love was always radio. But for most of us, he will always be remembered as the man behind the LA-2A."

The Birth of the Tool
Most people know that the LA-2A comes from the broadcast community, but few people know that the LA-2A's photo resistor also had military ties. While at Parsons Electronics, Lawrence was quietly asked to join the Titan Missile Program based at Cal Tech's Jet Propulsion Lab and assigned to develop optical sensors for the program. Fortunately for the audio community, the technology developed from Lawrence's work on the Titan Missile lead back to his more peaceful deployment of the optical sensor as the detector to his future Leveling Amplifier. The interaction of the luminescent panel with the photo resistors in the LA-2A's T4 are predominantly what gives the device its signature sound.

After returning to Parsons for a short time and then finishing school, Lawrence broke out on his own to start Teletronix, setting up shop in his hometown of Pasadena, California in 1958. Among the Teletronix line of broadcast products were conversion and transmitter tubes, emergency tone generators (remember those annoying EBS tests?), multiplex generators, all the way up to full-scale radio transmitters. Jim's first pass at his Leveling Amplifier was released as the Teletronix LA-1--around one hundred units were made. The units are extremely rare, but two owners are Richard Kaplan at the Indigo Ranch in Malibu (his studio is a certified vintage gear museum) and Glen and Melody Macready, family of Jim Lawrence, who still use the LA-1 at their own studio in Portland.

The Macready's LA-1 hand-me-down from kinfolk Jim Lawrence. Serial #15.
Clearly, the LA-1 was not a huge success; industry acceptance was difficult. In fact, the LA-1 got a harsh response after its demo at ABC, who complained about the messy point-to-point wiring. At this time, printed circuit boards were in vogue; but as gear-geeks know, point-to-point wiring is a desirable luxury and art that very few manufacturers still employ--UA's Teletronix LA-2A re-issue is among them.

Fortunately, Lawrence gets his LA-1 into the hands of the legendary singing cowboy Gene Autry, who himself loves the unit and uses the LA-1 for his own radio and recording dates. Gene Autry was instrumental in the LA-1 gaining momentum, for which Lawrence was always grateful.

Optical Catches Fire
Soon after, Lawrence updated the LA-1 to the LA-2. While still point-to-point, Jim laid out the wiring in a more concise manner, using turret boards. This is when the classic look of the LA-2A is realized. The canister detector evolves from the T1 to the T4. The ratio becomes gentler.

An important figure in the popularization of the LA-2 and the Teletronix line was engineer Sid Feldman. Feldman purchased an LA-2 early on, and soon became involved in distribution. He first took an LA-2 to Art Shine at CBS for him to try out on the Ed Sullivan Show. CBS immediately bought a pair. Soon after, RCA purchased units for their New York and Nashville operations. At this point, the Teletronix LA-2 began finding its way into recording studios, and musically speaking, the rest is history.

The beautiful inner workings of the original Leveling Amplifier
The Arrival
In 1962 Lawrence then began to reconfigure the LA-2 into the LA-2A, at which time the device gained the rear access Limit/Compress switch; perhaps to add versatility in response to the newfound interest from the recording industry. The LA-2A goes on to become the industry standard compressor along with Bill Putnam Sr.'s 1176, and the two have remained inextricably linked to this day. I like to think of the LA-2A and 1176 as the "Gibson Les Paul and Fender Stratocaster" of compressors--in that order. They are industry standard for a reason; they cover all the bases within just those two units-but my gear-geek self digresses.

In 1965, just three short years after the incarnation of the LA-2A, Jim Lawrence decides to sell the company. Teletronix went to Babcock Electronics in Costa Mesa California, where Lawrence stayed on as a consultant for a short time. Enter Bill Putnam. Putnam picked up Babcock's broadcast division and therefore Teletronix, and rolled them all into his parent company, Studio Electronics in 1967; Bill sent Jim a nice letter praising him for his technological contributions. From there, Universal Audio picked up manufacturing of the LA-2A, and Putnam began using the optical detector for new designs. The LA-3A, a solid-state version of the Leveling Amplifier was first, followed by the LA-4 and LA-5. Another product that utilized the optical detector and signaled a return to its broadcast roots was the UREI BL-40 Modulimiter, which used dual detectors and phase optimization; a contemporary to the broadcast industry standard, the Orban Optimod.

In his life, Jim Lawrence secured many patents, some for technology we commonly use today, such as detented pots. Jim also developed technology for the first LED (light emitting diode) metering for audio, but decided it was not that valuable, and unfortunately never secured a patent. Jim Lawrence was a talented inventor and technological pioneer; but his first love was always radio. He spent much of his working life in and around radio stations, furthering the technologies and techniques employed in the broadcast community, and servicing and designing radio stations all over Los Angeles and even in Mexico and Guatemala. But for most of us, he will always be remembered as the man behind the LA-2A.

LA-610 All Tube Recording Channel
"LA" for a New Generation- Introducing the LA-610
Optical compression not only has a rich history, but is alive and well in today's audio industry, and does not appear to be going away anytime soon. Universal Audio is continuing this legacy with the release of the LA-610 All Tube Recording Channel. The LA-610 borrows the T4 electro optical detector from the LA-2A and adds it into the 610 mic pre. Long live the T4! See this month's dissertation by none other than the enigmatic Professor Vacuum Tube this month in "Ask the Doctors".

Extra special thanks to Gretchen Lawrence and Glen Macready.

Bonus! UA Announces New Precision Preamplifier!
I've been holding this one in for quite some time. I'm really excited about this new product, and its with great pleasure I get to talk about UA's upcoming Precision Preamplifier. As I will be manning the analog demo station, I will personally give you a demo at the upcoming AES in San Francisco!

Universal Audio's 8110 Eight Channel Precision Mic Pre
Design Goals
The design goals for the Precision line were uncompromised sound quality and recording functionality while maintaining a tremendous per-channel value. With this as a foundation, UA set out to create a brand new type of preamp design that would satisfy these "Precision" requirements:
  • A tonally versatile Class-A unit with a wide spectrum of useful sounds to handle multi-channel applications

  • Hold its own with the best modern, ultra-clean units but have enough variable "tone" or "drive" for rock/pop

  • Offer huge amounts of gain (80dB) and impedance options to handle the best mic cupboards

  • Create an innovative unit with its own sonic signature combining classic design philosophy, modern topology, with modern components

  • Be true to the heritage and musicality standards set by the historical tube and solid-state classic UA preamps
The Precision Microphone Preamplifiers are for the audio engineer in need of the absolute best in sonic quality, regardless of cost. The innovative 8110 and 4110 provide respectively eight and four channels of premium Class A, all discrete amplification, utilizing strict design rules to achieve an ultra-clean, transparent, high-headroom mic pre. With emphasis on lightning fast transient response, wide dynamic range and frequency response, the Precision Mic Pre is the first analog product from Universal Audio to offer a totally original design-- a world-class tool of "ultra-fidelity" that still provides musical and warm euphonics.

Every channel of the Precision features dedicated Gain and Level controls, input and output metering, dual input impedance selection, and a 3-way "Shape" switch offering a variable signal-path for maximum sonic versatility. Position one is perfect for a modern preamp sound, no coloration added. Position two borrows from vintage circuits and adds transformer saturation, enhancing harmonic content. Position three maintains transformer saturation and adds soft limiting, particularly useful on transient rich and dynamic sounds.

3-Way "SHAPE" Switch
Modern: Ultra-clean, transparent, maximum headroom
Vintage: Transformer-loaded with harmonic enhancement
Saturate: Transformer-loaded with soft-limiting

  • 8 or 4 Channel Class A mic-preamp, lightning-fast transients, high-headroom, ultra-low noise, class-leading 80dB gain

  • Gain and Level controls allow for ultra-clean and transparent to colored signal path

  • 3-way "SHAPE" switch offers Modern/Vintage/Saturate tonal flavors via variable signal-path for maximum sonic versatility

  • Optimum signal path design- direct coupled, discrete components, input transformers, no capacitors in audio chain

  • Achieves clean, transparent mic amplification with enormous dynamic and frequency range

  • Ultra-clean, with incredible headroom and a class-leading 80dB of gain

  • Gain and Level controls allow for ultra clean and transparent to subtly colored signal path

  • Shape control, produces increased harmonic content, subtle peak limiting, and warmth

  • All class A, direct coupled, discrete components, input transformers, no capacitors in audio

  • Independent Input and Output metering

  • Multi-channel mic pre gives per channel cost savings

  • XLR Mic connectors, line connectors on a D-sub 25 pin.

  • Mic XLR connections, TRS line connections as well as front panel Hi-Z inputs on 4110

-Will Shanks

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