Note: All pictures are of the actual real item that is being sold here.

Introduction

This 500 series Safe Sound Audio Stereo Toolbox compressor for sale here is my carefully looked after previously owned unit in immaculate fully operational condition. I have had this unit from new (bought from KMR in London) and everything works perfectly, like the day I bought it. It has seen limited use and has been kept in a clean, dry, smoke free home.

Why is this compressor looking for a new home?

As a dance music producer, I bought this compressor intending to integrate it into my studio workflow, but it has seen very little use and has spent most of its time stored in its box. I held onto it with plans for a dedicated studio setup, but I no longer have the time or space to pursue that. I've therefore decided to sell my 500-series gear, giving someone else the opportunity to enjoy this unique top quality unit.

Background

Discover a rare gem in the world of professional audio processing: the Safe Sound Audio Stereo Toolbox Compressor. This API 500-series module is the first of its kind to offer both conventional stereo and mid/side (M/S) compression in a compact Lunchbox format. Built in the UK with exceptional craftsmanship, it delivers pristine, clean compression with subtle harmonic coloration options, making it an indispensable tool for mix engineers and mastering professionals alike.

Why You Need This Compressor :)

• Unique API 500-series module offering both stereo and mid/side compression.

• Perfect for mix bus, stem mastering, or individual sources.

• Includes sweepable high-pass filter for audio and side-chain signals.

• Detented controls for precise matching and easy recall.

• Built with Cinemag output transformers for superior audio quality.

• Compact 2-slot design with intuitive layout and bright LED metering.

• Designed and hand-built in the UK for professional reliability.

Technical Specifications

• Frequency Response: -0.25 dB at 10 Hz, -0.5 dB at 70 kHz.

• Input: Electronically balanced, >10 kΩ impedance, handles up to +24 dBu.

• Output Noise: -90 dBu RMS unweighted (22 Hz–22 kHz), -92 dBu RMS A-weighted.

• Compression Ratio: 1:1 to 30:1 (limiting), with fine detented adjustments.

• Attack Time: Fast (1 ms) or Slow (10 ms) selectable.

• Release Time: Program-dependent, 50 ms to 1.5 s.

• High-Pass Filter: Sweepable from 17 Hz to 2.1 kHz at 12 dB/octave; assignable to mono side-chain or Sides signal.

• Threshold Range: +13 dBu to -27 dBu (via 'Drive' control).

• Make-Up Gain: ±15 dB, with precise detents.

• Maximum Output Level: +28 dBu at 1 kHz, +24 dBu at 50 Hz.

• Harmonic Distortion Modes: Low-color (0.06% up to 500 Hz, <0.02% above 1 kHz) or High-color (0.2–1% up to 500 Hz, ~0.04% above 1 kHz).

• Metering: Dual six-segment LED meters for input level or gain reduction.

• Build Quality: Robust 2-slot API 500-series module with logical control layout.

Additional Details
• Worldwide shipping available at buyer’s expense; contact for quote.

• All local taxes / import duties also payable by buyer; please check before purchasing.