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LA-3A Compressor Manual

A refresh for a legendary solid-state electro-optical compressor.

If you took the gentle optical compression of the Teletronix LA-2A, and fused it with the solid-state clarity and punch of the UA 1176, you would have the Teletronix LA-3A — a "secret weapon" compressor with a unique character capable of moving sounds right to the front of your speakers.

Now featuring improved user interface graphics and sonic appointments, the refreshed Teletronix LA-3A Audio Leveler plug-in for UAD-2, Apollo interfaces, and Native UAD processing, takes its rightful place alongside the pillars of classic compression hardware.

  • Easily shape signals with the definitive solid-state optical compressor
  • Add grit and texture to bass guitar and soft synths
  • Add energy and harmonics to vocals and acoustic guitars
  • Sculpt your sounds further with new HF Emphasis sidechain filter and parallel Dry/Wet Mix
  • Make snare drums pop out of the mix
  • Mix with artist presets from Mark Needham (Imagine Dragons, Fleetwood Mac), Damian Taylor (Björk, The Prodigy), and Eric J Dubowsky (Flume, Odesza) and more

LA-3A History

The Teletronix LA-3A Audio Leveler made its debut at the 1969 NY AES show, and marked the departure from the tube design of the Teletronix LA-2A. The LA-3A incorporated components and design concepts from UA’s solid-state driven 1176LN Limiting Amplifier, while also harnessing the LA-2A’s optical compression design, giving the LA-3A its own distinctive sound and expanded versatility.

A Proven Winner

Immediately embraced as a studio workhorse, the LA-3A is still widely used today. Engineers and producers the world over favor the LA-3A for its unique compression characteristics and sonic signature. Modeled from a unit in UA’s vintage collection, the Teletronix LA-3A Audio Leveler plug-in faithfully captures the rare hardware, working magic on vocals, guitars, and even drums.

New Modern Features

By adding the hardware’s original HF Emphasis sidechain filter, you can now easily use the Teletronix LA-3A plug-in punch up your drum bus without triggering the threshold of the compressor with the kick drum. Plus, a new Dry/Wet Mix control lets you easily add parallel compression on an instrument bus, allowing you to season your productions with legendary Teletronix LA-3A attitude.

Artist Presets

Teletronix LA-3A includes presets voiced by prominent Universal Audio artists. The artist presets are in the internal factory bank and are accessed via the preset manager.

Carl Glanville
Chris Coady
Chris Zane
Chuck Zwicky
Damian Taylor
Dave Isaac
Eric J Dubowsky
J.J. Blair
Jeff Balding
Joe Chiccarelli
Mark Needham
Mike Poole
Nick McMullen
Richard Chycki
Ross Hogarth
Steve Levine

Artists that have provided presets for Teletronix LA-3A


Teletronix LA-3A Audio Leveler interface

Teletronix LA-3A Audio Leveler Controls


The Gain knob increases the output level to compensate for the reduced level that results from compression. Adjust the Gain control after the desired amount of compression is achieved with the Peak Reduction control. The Gain control does not affect the amount of compression.

Note: The front panel knob values, which range from 0-10, are arbitrary and do not reflect any particular dB value.

Peak Reduction

This control sets the amount of signal compression by adjusting the trigger threshold. Increasing the value lowers the threshold, and therefore increases the amount of compression.

Note: The front panel knob values, which range from 0-10, are arbitrary and do not reflect any particular dB value.

Rotate this control clockwise until the desired amount of compression is achieved. To monitor the amount of Peak Reduction, set the VU Meter knob to Gain Reduction. Peak Reduction should be adjusted independently of the Gain control.

When Peak Reduction is set to its minimum value, no compression (or limiting) occurs but the signal is still colored by the circuitry and the output level can be adjusted with the Gain control.


Tip: Click a switch label to quickly switch to that mode.

This switch sets the compression ratio of the leveler. When set to Compress (COMP), the compression ratio is approximately 3:1 and when set to Limit (LIM), the ratio is approximately infinity:1. However, the compression ratios are nonlinear and frequency dependent, so these figures are not absolute.

VU Meter

The VU meter displays the amount of gain reduction or the output level. The mode being displayed depends upon the setting of the Meter Select switch. When the meter is dim, the plug-in is bypassed with the Meter Select switch or the host’s bypass switch.

Note: When set to Output, the meter displays the wet, processed signal level only.

Meter Select

This switch sets the mode of the VU Meter and also disables the plug-in. When Meter Select is set to GR, the VU Meter indicates the amount of gain reduction in dB. When set to output, the VU Meter reflects the relative level after the Gain control.

Tip: Click a switch label to quickly switch to that mode.

When in the Off position, plug-in processing is disabled, the VU Meter dims, and processor usage is reduced.

Note: UAD-2 DSP usage is reduced only when DSP LoadLock is disabled in the UAD Meter & Control Panel application. If DSP LoadLock is enabled (the default value), setting the switch to Off will not reduce DSP usage.

High Frequency Emphasis (HF)


The High Frequency Emphasis "set screw" controls a shelf filter circuit in the compressor's sidechain input, thereby enabling frequency-dependent compression.

Tip: Click the "+" or "-" text labels to increment or decrement the current value in tenths. Click the "HF" text label to return to the default value.

When the control is fully clockwise (the default position), the sidechain signal is unfiltered and all frequencies in the source signal that exceed the compression threshold will trigger gain reduction equally (within the non-linear constraints of the electro-optical characteristics).

Rotating the HF control counter-clockwise increases filtering of the sidechain signal. The High Frequency Emphasis filter gradually reduces the lower frequency content of the sidechain signal, resulting in compression that is less sensitive to those frequencies, and more sensitive to high frequency content. Therefore, as the sidechain filtering is increased, higher frequencies are compressed more.



Tip: Click the "+" or "-" text labels to increment or decrement the current value in tenths. Click the "MIX" text label to set the value to 50%.

A blended output balance between the signal processed by the plug-in and the original dry source signal can be adjusted with the Mix "set screw" control. Mix facilitates parallel compression techniques without having to create additional routings in the DAW.

Note: The Mix control does not exist on the original hardware.

When Mix is set to 0% (fully counter-clockwise), only the unprocessed dry source signal is output. When set to 100% (fully clockwise, the default value), only the processed wet signal is output. When set to 50% (12 O’Clock noon position), an equal blend of both the dry and wet signals is output. The balance is continuously variable, and phase accurate, throughout the control range.


The original Teletronix LA-3A hardware unit