KERWAX VM-124 – Vari-Mu Mono Tube Compressor

OVERVIEW

The KERWAX VM-124 is a boutique Vari-Mu mono tube compressor that pays homage to the classic EMI RS124/Altec 436 design while enhancing it with expanded control and modern performance. Designed and fully hand-built in France with premium locally sourced components, it combines retro-inspired tone with today’s studio demands.

Perfect across the full audio spectrum, the VM-124 shines on vocals, bass, acoustic instruments, and more. Its creamy, harmonically rich compression adds warmth and depth, while stepped attack, release, and output controls allow precise, repeatable settings. Whether you want smooth leveling, subtle glue, or bold character, the VM-124 delivers timeless analog dynamics with unmistakable tube flavor.

KEY HIGHLIGHTS

Classic Vari-Mu Design:

Inspired by the legendary EMI RS124/Altec 436, updated with versatile stepped controls.

Creamy, Musical Compression:

Adds warmth, depth, and vintage tube character to vocals, bass, and instruments.

Handcrafted Boutique Build:

Meticulously built in France with high-quality components and UTM transformers.

Flexible Tube Stage:

Switch to “Comp Off” mode to use the tube stage alone for added coloration.

Precise, Repeatable Control:

11-step attack and release, plus stepped output, make dialing in compression simple and reliable.

FEATURES

• Retro-Inspired Circuit: Based on the EMI RS124/Altec 436 with modern enhancements
• Mono Vari-Mu Design: Smooth, tube-driven dynamic control
• Stepped Attack Control: 11 positions, from 3 ms up to 138 ms
• Stepped Release Control: 11 positions, from 127 ms up to 6 seconds
• Stepped Output Control: 6 positions (-20 dB to 0 dB) for precise level matching
• Comp Off Mode: No compression, just tube coloration from input to output
• True Bypass: Preserves signal integrity when not in use
• UTM Transformers: High-quality transformers on both input and output
• Handcrafted in France: Premium construction with locally sourced parts

TECHNICAL SPECS

Design: Vari-Mu mono tube compressor, inspired by EMI RS124/Altec 436

Rack Size: 2U rackmount unit

Tubes:

• 2 × 6N1P
• 1 × 6AL5

Transformers: UTM transformers (input and output)

Bypass: True Bypass

Operating Modes:

• Comp Off: No compression, tube stage coloration only
• Comp On: Vari-Mu compression engaged
  • Attack: 11 steps, 3 ms – 138 ms
  • Release: 11 steps, 127 ms – 6 s

Output Control: 6 steps (0 dB, -5 dB, -10 dB, -15 dB, -20 dB)

Construction: Fully balanced – handcrafted in France