The Teletronix LA-3A was truly diminutive when compared to it’s predecessors like the Teletronix LA-2A and even the Urie 1176. What it lacked in size it well and truly made up for in performance. It was often sold in pairs and rack mounted, taking up a 2U space within the rack.
The Teletronix LA-3A Solid State Leveling Amplifier is the solid-state successor to the well-known Teletronix LA-2A. The unique characteristics of the T4A electro-optical attenuator have been maintained. It is these characteristics that have been greatly responsible for the acceptance and worldwide popularity of LA-2A’s.
Improvements in overload characteristics and signal to noise ratio add to the performance and utility of the Teletronix LA-3A. The new 1/2 rack size allows installation of two LA-3A Leveling Amplifiers in only 31/2 inches of rack space. Contemporary styling complements existing studio equipment.
The Teletronix LA.3A consists of a low noise, 30 or 50 dB gain solid state amplifier capable of 4-24 dBm output level in normal application. The T4B electro-optical attenuator is used as a dynamically controlled attenuator ahead of the input stage of the amplifier. The gain reduction control and the gain control are independent and provide for simple and convenient setting of the limiting or compressing action, and the system gain.
Limiting frequency response is adjustable to allow as much as 10 dB increase in gain reduction at 15kHz compared to frequencies below 1 kHz. This is advantageous in FM and TV transmission where pre-emphasis is used.
A switch is provided to change the characteristics from those of a compressor (linear gain reduction) to those of a limiter (a compression ratio approaching 50: 1 where the dynamic content of the program material necessitates a large amount of limiting). The electro-optical attenuators of two Teletronix LA-3A units may be connected in tandem for stereo operation.
