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Alice 538T

Compressor / Limiter

The Alice 538T Lunchbox Stereo OPTO is designed for creative compression effects that are difficult to achieve with plug-ins.


Original price was: €775.Current price is: €735.

SKU: 108234


The Alice 538T OPTO Stereo Compressor v2, equipped with transformer outputs, is a versatile and high-quality compressor designed for creative compression effects and precise leveling. Here are the details:


  1. Pedigree:
    • Incorporates Ted Fletcher’s historic opto compression design.
  2. Bypass:
    • Perfect ‘Hard-Wired’ bypass for instant comparisons.
  3. Ratio:
    • Wide range ratios from gentle to brutal.
  4. Metering:
    • Accurate UV compression metering on a real meter.
  5. Stereo Width Control:
    • Extreme stereo width control for creative sound shaping.
  6. Occupancy:
    • Occupies two spaces in a standard API 500 series rack.
  7. Inputs & Outputs:
    • Left and Right balanced or unbalanced inputs.
    • Left and Right balanced outputs via hand-matched OEP Z3001C canned transformers.
  8. Width Control (Stereo Imaging):
    • Processes audio signal into ‘sum and difference’ mode for perfect stereo symmetry.
    • Width control adjusts stereo width with the volume level of the ‘difference’ channel.
  9. Meter Reading:
    • Easy-to-read analogue meter reading audio (UV) or compression depth (comp).


  1. Inputs:
    • 10K impedance differential balanced.
  2. Outputs:
    • Floating balanced 50 ohm.
    • Max balanced output approximately +26dBu.
  3. Gain:
    • Maximum 24dB.
  4. Noise:
    • At least 80dB below operating level. Dynamic range exceeds 100dB.
  5. Harmonic Distortion:
    • Generally within 0.005%. 2nd order harmonic distortion rises at lower frequencies under compression.
  6. Frequency Response:
    • Line in 20Hz to 20KHz within 1dB.
  7. Audio Crosstalk:
    • Uses M/S processing (sum and difference) with ‘side’ content variable via the width control.
    • With width set at 100%, L/R crosstalk can be better than -50dB.
  8. Compressor:
    • Photoresistive servo-operated feedback type.
    • Ratio non-linear; minimum approx. 1.2 to 1, maximum approx. 8 to 1.
    • Sidechain filtered for correct bass compression.
    • Attack time 1mS min, 10mS max (variable).
    • Release time 200mS min, 1.5S max (variable).
  9. Connections:
    • Via 2 X 500 series sockets.
  10. Power:
    • 3 Watts. Powered from 500 series rack.
    • +ve rail 68mA, -ve rail 106mA.
  11. Housing:
    • 2 spaces of 500 series rack.

This compressor is not only a creative tool for unique compression effects but also functions as a high-quality leveling amplifier with the character of a well-designed opto compressor. Its wide range of features, including stereo width control and accurate metering, makes it a valuable asset in professional audio applications. The 538T’s design and specifications showcase its commitment to delivering top-notch audio processing capabilities.