Silent Power by ifi Audio DC Blocker+

The DC Blocker+ from iFi Audio offers a targeted solution for eliminating electrical interference that degrades amplifier sound quality. This compact power conditioner directly addresses the issue of residual DC current present on the home electrical network, which is responsible for unwanted transformer hum. Designed for high-power equipment, it installs simply between the amplifier and its power cable, without compromising electrical safety or shielding against electromagnetic interference.

Thoughtful Physical Design and Ergonomics

The DC Blocker+ features an especially compact format of 75 × 46 × 32 mm and weighs just 80 grams. This smart miniaturization prevents clutter around other connectors and cables near the amplifier. The enclosure, made from UL94-V0 certified flame-retardant polymers, ensures maximum safety, while medical-grade IEC connectors provide a reliable and durable connection.

Its clean white aesthetic blends discreetly into any hi-fi environment. The two IEC connectors—a male to plug into the amplifier and a female to receive the original power cable—allow for completely transparent installation. This minimalist approach contrasts with traditional power conditioners that require bulky enclosures and extra cables.

ZERO DC Block Technology: A Targeted Approach

At the heart of the DC Blocker+ is the proprietary ZERO DC Block technology, capable of blocking up to 1,200 mV of DC voltage. This performance is made possible by a high-performance glass-passivated semiconductor, offering a high dielectric strength of 1,500 VRMS.

The problem of DC current on the mains originates from “asymmetrical loads” created by many household devices, from dimmer switches to electronic power supplies. When this electrical pollution reaches an amplifier’s transformer, it can cause saturation, resulting in a persistent and audible mechanical hum.

The larger the toroidal transformer—as is often the case with high-power amplifiers—the more sensitive it is to this continuous pollution. The DC Blocker+ acts upstream to intercept these parasitic voltages before they reach the transformer, thus preserving the amplifier’s silent operation.

Practical Installation and Use

Installing the DC Blocker+ couldn’t be more straightforward. Simply connect its male IEC connector to the amplifier’s power input, then plug the original power cable into the device’s female connector. No adjustments are necessary; filtering operates automatically.

This installation simplicity conceals advanced technical design. The device fully preserves the original EMI (electromagnetic interference) shielding of the setup. Electrical safety remains unchanged, with all amplifier protection devices remaining fully operational.

Broad Compatibility and Robustness

The DC Blocker+ accepts a particularly wide voltage range, from 90 to 250 V, giving it universal compatibility. Its continuous nominal current of 10 A allows use with amplifiers up to 2,200 W at 220 V or 1,100 W at 110 V.

This current capacity places the DC Blocker+ among the conditioners suitable for the most powerful amplifiers on the home market. The maximum allowable current can even reach 14 A peak, providing a valuable safety margin.

The DC Blocker+ can be paired with the GND Defender from the same manufacturer to simultaneously address ground loop and DC pollution issues. This modular approach allows precise adaptation of treatment to the specifics of each setup.

Technical Specifications

Technology and Performance

• ZERO DC Block Technology
  • Eliminates up to 1,200 mV of direct current at the input
  • Removes transformer hum
• Universal Compatibility
  • Operates with voltages from 90 to 250 V
  • Usable worldwide
• Maintained Safety and Shielding
  • EMC filtering preserved
  • No compromise on device safety

Electrical Specifications

• Rated current: 10 A
• Maximum current: ≤ 14 A
• Maximum amplification power
  • 2,200 W at 220 V
  • 1,100 W at 110 V
• Suitable for high-power equipment

Connectivity and Design

• Medical-grade IEC connectors
• Durable, flame-retardant materials (UL94-V0)
• Compact format
  • Does not obstruct nearby outlets or cables
• Net weight: 80 g

Installation and Contents

• Easy installation
  • Plug the male IEC connector of the DC Blocker+ into your device’s power input
  • Connect the original cable to the female IEC socket of the DC Blocker+
• Box contents
  • 1 × DC Blocker+
  • 1 × quick start guide

Specifications Summary

• Rated voltage: 90 – 250 V
• Max DC blocking: up to 1,200 mV
• Rated current: 10 A
• Maximum current: ≤ 14 A
• Max amplifier power: 2,200 W (220 V) / 1,100 W (110 V)
• Connectors: IEC (medical grade)
• Net weight: 80 g