The material of IEM (In-Ear Monitors) cable connectors—both pins and plugs—plays an important role in signal transmission quality, durability, and electrical resistance. While its impact is smaller compared to the conductor material, in hi-end audio, every detail matters. In this article, we will explore the most common materials used in IEM connectors, their advantages and disadvantages, and how they affect the overall listening experience.

Common Materials Used for IEM Connectors

Brass (CuZn)

• Description: One of the most widely used materials for both pins and plugs.
• Pros:
  • High mechanical strength.
  • Good corrosion resistance.
  • Affordable and easy to manufacture.
• Cons:
  • Lower conductivity than copper.
  • Can oxidize over time without protective coating.
• Commonly used for: Pins and plugs in mid-range and budget segments, usually gold or rhodium plated.

Phosphor Bronze (CuSnP)

• Description: A strong copper alloy with phosphorus and tin, often used in connectors for enhanced durability.
• Pros:
  • High wear resistance.
  • Good elasticity, essential for stable contact.
  • Corrosion resistant.
• Cons:
  • Lower conductivity than pure copper.
  • Requires protective coating for maximum longevity.
• Commonly used for: Pins in IEM connectors, especially with rhodium plating.

Oxygen-Free Copper (OFC)

• Description: High-purity copper with minimal oxygen content.
• Pros:
  • Excellent electrical conductivity.
  • Low resistance.
• Cons:
  • Very soft metal, easily prone to mechanical damage.
  • Rapid oxidation if left uncoated.
• Commonly used for: Premium-grade plugs, usually gold or silver plated.

Beryllium Copper (BeCu)

• Description: A copper alloy with beryllium, offering high strength.
• Pros:
  • Exceptional mechanical strength.
  • High elasticity, crucial for stable connections.
• Cons:
  • More expensive to manufacture.
  • Requires coating to prevent oxidation.
  • Lower conductivity than pure copper.
• Commonly used for: Pins in IEM connectors, especially thin and flexible ones.

Tellurium Copper (TeCu)

• Description: A copper alloy with tellurium, enhancing mechanical properties.
• Pros:
  • Good corrosion resistance.
  • Easier to machine than pure copper.
  • High durability.
• Cons:
  • Lower conductivity than pure copper.
• Commonly used for: High-end pins and plugs where maximum conductivity and strength are needed.

When discussing conductivity, we compare it to the benchmark of annealed copper. In audio connectors, this value is quite relative, and its true impact on sound is minimal.

Which Connector Material Should You Choose?

Conclusion

Choosing the right connector material for IEM cables depends on conductivity, durability, and cost. In most cases, connectors are coated with rhodium, gold, or silver to protect them from corrosion. Pins are most commonly made of brass and beryllium copper, as they provide the necessary strength. Plugs are usually made of brass, copper, and phosphor bronze, as they are easy to process and ensure a reliable connection.

For audiophiles, pure copper connectors are available, but they require regular maintenance and cleaning to prevent oxidation.

At Zikman, we use premium materials for connectors, ensuring pure sound and long-lasting durability.