Sigma Tube Cardioid Microphone

The SIGMA Series from Edax Audio Labs represents the perfect fusion of vintage soul and modern precision. Each of the three standard cardioid models is built with a sleek, contemporary design, featuring a high-strength zinc die-cast body finished in an ultra-resistant electrophoretic coating for lasting beauty and durability.At the heart of each microphone lies a meticulously engineered circuit inspired by the golden era of the 1960s.

The subminiature vacuum tube —crafted by the legendary Raytheon to uncompromising military specifications— delivers unmatched longevity, ultra-low noise, and an authentic sonic character that only true vintage components can provide.This timeless circuitry is paired with a state-of-the-art toroidal output transformer, hand-built in our own facilities with absolute precision by master technicians.

The result is a level of performance that surpasses even the finest quasi-toroidal designs found in original vintage units or modern replicas.Every SIGMA microphone is individually voiced to perfectly match its capsule, ensuring maximum tonal integrity and performance.

The ED-4012, ED-4047, and ED-4067 each embody the spirit of the iconic capsules of the 1950s and 1960s—timeless designs that have defined generations of recordings—crafted with exacting tolerances and subjected to rigorous quality control.

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Key Features

  • Vintage-Inspired Electronics – 1960s-style circuit with a genuine Raytheon subminiature vacuum tube, built to military specifications for exceptional reliability and extended lifespan.
  • Premium Output Stage – State-of-the-art toroidal output transformer, hand-crafted in-house to outperform quasi-toroidal designs found in most vintage and replica microphones.
  • Precision-Matched Capsules – Three capsule styles (ED-4012, ED-4047, ED-4067) inspired by the legendary CK12, K47, and K67 designs, each tailored for optimal tonal performance.
  • Rugged Construction – High-strength zinc die-cast body with ultra-durable electrophoretic coating finish.
  • Hand-Built Quality – Crafted in our own facilities under strict tolerances, with rigorous testing to ensure consistent performance.

Models

  • ED-4012 – Open, detailed high-end with silky smooth mids.
  • ED-4047 – Warm, rounded low-end with rich vintage character.
  • ED-4067 – Balanced tone with extended clarity and presence.

Applications

Ideal for:

  • Vocal recording
  • Acoustic instruments
  • String ensembles
  • Broadcast and voiceover
  • Studio and live performance

Specifications (typical)

  • Body Material: Zinc die-cast with electrophoretic coating.
  • Frequency Response: Tailored to capsule type.
  • Manufacturing: Hand-built in our own facilities.

Technical Information

Capsule Type: ED-4012 Edge Terminated Large Diaphragm.

Capsule Type: ED-4047 Center Terminated Large Diaphragm.

Capsule Type: ED-4067 Center Terminated Large Diaphragm.

Transformer: Edax Toroidal output transformer.

Impredance: 200 Ω

Ck12, K47&K67 Capsules style.

Polar Pattern: Cardioid

Frequency Response: 20 Hz to 20KHz ±3 dB

Distortion: < 1% @ 134 dB SPL

Self Noise: 14dB nominal, not to exceed 16dB (A weighted)

Kit: Include  Microphone, power supply, shock mount, 5mt audio 5 XLR cable.

with  protective  plastic case with custom molded foam.

Dimensions: 53mm x 43mm x 150mm

Weight: 428 g

“In order to ensure continuous innovation and enhancement of our products,

technical  specifications may be subject to change without prior notice.”