User manual

UAD Powered Plug-Ins Manual - 122 - LA-2A and 1176LN
Most modern compressors provide a control that adjusts the threshold di-
rectly. In the case of the LA-2A, the Peak Reduction control adjusts both the
threshold and the amount of gain reduction. Similarly, the 1176LN uses its In-
put control to adjust the threshold and amount of gain reduction.
Teletronix LA-2A Leveling Amplifier
Background Audio professionals passionate about their compressors revere the LA-2A.
The original was immediately acknowledged for its natural compression char-
acteristics. A unique electro-optical attenuator system allows instantaneous
gain reduction with no increase in harmonic distortion – an accomplishment
at the time, still appreciated today.
The LA-2A is known for adding warmth (such as for vocals, guitar, or synths)
and fatness (such as for drums or bass) to signals.
LA-2A Signal
Flow
A functional block diagram of the LA-2A Leveling Amplifier is provided in
Figure 43. The input transformer provides isolation and impedance matching.
After this the signal is fed into both the side-chain circuit and the gain reduc-
tion circuit. The side-chain is comprised of a voltage amplifier, a pre-emphasis
filter, and a driver stage that provides the voltage necessary to drive the elec-
tro-luminescent panel. This signal controls the gain of the compressor. After
the gain reduction circuit, the signal is sent through an Output Gain control
and a two-stage output amplifier, followed by the output transformer.