LA-2A Leveling Amplifier
Encyclopedia
The LA-2A Leveling Amplifier is an audio compressor originally produced by Teletronix in 1965. Three versions of the LA-2A were made until 1969. The LA-2A was inducted into the TECnology Hall of Fame in 2004.
The LA-2A is a hand-wired, tube-based, compressor. It uses an electro-luminescent
panel together with a cadmium-sulfide light dependent resistor
to provide gain reduction, which, in the LA-2A, is called the T4 cell. The properties of the T4 give the LA-2A its unique character by making it an entirely program dependent design. The attack time is 10 milliseconds and 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.
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 alter the compression ratio. The VU meter may also be switched to show gain reduction or output level.
The LA-2A has a sonic character that make it sought after by many recording engineers.
The LA-2A is a hand-wired, tube-based, compressor. It uses an electro-luminescent
Electroluminescence
Electroluminescence is an optical phenomenon and electrical phenomenon in which a material emits light in response to the passage of an electric current or to a strong electric field...
panel together with a cadmium-sulfide light dependent resistor
Photoresistor
A photoresistor or light dependent resistor is a resistor whose resistance decreases with increasing incident light intensity. It can also be referred to as a photoconductor or CdS device, from "cadmium sulfide," which is the material from which the device is made and that actually exhibits the...
to provide gain reduction, which, in the LA-2A, is called the T4 cell. The properties of the T4 give the LA-2A its unique character by making it an entirely program dependent design. The attack time is 10 milliseconds and 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.
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 alter the compression ratio. The VU meter may also be switched to show gain reduction or output level.
The LA-2A has a sonic character that make it sought after by many recording engineers.