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ONE LA 500

Classic Tube Opto-Compressor

ONE LA 500 brings the timeless sound of the classic LA-2A opto compressor into the compact 500-series format—without compromise. Designed as a true high-voltage tube module, it operates internally at 250 V DC via an onboard converter, ensuring authentic tube behavior in any standard 500-series rack. With just two knobs and a compressor/limiter switch, ONE LA 500 delivers effortless, musical compression that enhances vocals, strings, bass, and drums with rich harmonics and smooth dynamics. Used as a stereo pair, it also excels as a warm, characterful bus compressor.
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Classic Opto Compression in a 500-Series Format
ONE LA 500 is a high-voltage, tube-driven opto compressor inspired by the legendary Teletronix ’68 LA-2A. Unlike typical 500-series designs, it runs its tubes at a true 250 V DC, preserving the response, depth, and harmonic structure that define classic opto compression.

Simplicity That Delivers Results
With only two controls and a compressor/limiter switch, ONE LA 500 is intentionally straightforward. This minimal interface encourages fast decisions while delivering consistently musical results across a wide range of sources.

Hand-Built with Premium Components
Each unit is hand-assembled using carefully matched 1% metal-film resistors, Wima capacitors, and JJ tubes. Every ONE LA 500 is individually calibrated to ensure consistency, reliability, and authentic performance.

Transformer-Balanced, Studio-Ready Design
Three audio transformers—IGS Custom units in the signal path and an OEP transformer in the sidechain—provide depth, punch, and excellent isolation. A user-replaceable photocell further extends serviceability and longevity.

From Tracking to Bus Compression
Equally at home on vocals, strings, drums, and bass, ONE LA 500 can also be paired for stereo operation, making it a powerful and characterful bus compressor for modern hybrid workflows.

Specifications

Device Type Optical Compressor
Hard Wire Bypass Yes
Stereo Link Yes (custom order)
Audio Transformers Yes, IGS Custom
Input Impedance
Balanced
600 Ω, IGS Custom transformer
Output Impedance
Balanced
600 Ω, IGS Custom transformer
Operating Level +4 dBu
Maximum Input Level +20 dBu
Maximum Output Level +21 dBu
Dynamic Range 100 dB
Maximum Gain Reduction 32 dB
Maximum Gain 32 dB
Noise Level −99 dBA
Attack Time 10 ms
Release Time 0.5 – 5 s (50% @ 60 ms)
Ratio 4:1 (COMP), 100:1 (LIM)
Frequency Response 8 Hz – 20 kHz ±1 dB
THD+N 0.002% @ 0 dBu
Power Supply API standard with internal DC-DC conversion (250 V DC tube supply)
Power Consumption 8.16 W
Slot #1: 190 mA @ +16 V, 170 mA @ −16 V
Slot #2: 150 mA @ +16 V, 0 mA @ −16 V
Shipping Weight 3 kg
VU Meter Yes, backlit GR meter
Tube Complement ECC802, ECC803

Downloads

One LA 500 Manual

One LA 500 Recall Sheet

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Products
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500 Series Atas Audio

500 Series

500 Series Chassis

500-Series Chassis

Dynamics Atas Audio

Dynamics

Equalizers Atas Audio

Equalizers

Monitor Controllers Atas Audio

Monitor Controllers

Noise Gates Atas Audio

Noise Gates

Preamplifiers Atas Audio

Preamplifiers

Signal Distribution Atas Audio

Signal Distribution

Studio Monitors Atas Audio

Studio Monitors

Channel Strips

Channel Strips

Saturation

Saturation

MPE Keyboards Atas Audio

MPE Keyboards

Mid Side Processing

Mid-Side Processing

Reverb Atas Audio

Analog Reverb

Drawmer

Telegrapher

Garbage Ideas

Z&H Designs

Mesanovic

IGS Audio

Expressive E

Looptrotter

HLabs