iFi Audio
iFi DC Blocker
Best solution for audiophiles struggling with annoying amplifier transformer hum.
The iFi DC Blocker is an innovative audio accessory designed to eliminate annoying transformer hum in amplifiers. This hum is often caused by residual DC voltage in AC power lines, which can saturate the amplifier's toroidal transformer. By placing the DC Blocker at the IEC power inlet, it effectively stops DC from entering the amplifier, ensuring the transformer operates optimally and eliminating audible hum. It retains EMI shielding and features a compact design that won't interfere with other connections. The device utilizes iFi's ZERO DC Block technology and hospital-grade IEC connectors for reliable performance and safety.
$129.00
Owner Satisfaction
4.5
/ 5
Category Rank
38
/ 142
#38 in Audio & Video Receiver Accessories
Price vs Category Average
-34%
Below average
Who it's for
- Audiophiles distracted by mechanical transformer buzzing
- Listeners seeking maximum clarity and soundstage definition
- Users wanting an effortless, tool-free power upgrade
Who should skip it
- Minimalists avoiding extra cables and clutter in their system
- Budget-conscious buyers prioritizing general upgrades over specific fixes
- Users without measurable DC offset in their power supply
Performance breakdown
Hum Elimination
Effectively silences mechanical transformer buzz caused by residual DC voltage.
Signal Integrity
Maintains EMI shielding to ensure audio purity remains completely uncompromised.
Build Quality
Utilizes fireproof polymers and high-grade components for long-term reliability.
Form Factor
Compact design fits easily into tight spaces without obstructing adjacent ports.
Safety Standards
Hospital-grade connectors provide professional-level security for your sensitive audio equipment.
Compatibility
Broad voltage support, though power limits restrict use with massive amplifiers.
Key Specs
Blocks incoming DC up to 1,200mV
Voltage rating
90 – 240 volts
Maximum current rating
> 7A
Max amplifier power
440W or VA on 110v; 880W or VA on 220v
Continuous current rating
4A
Dimensions
2.7” x 1.5” x 1.3”
Weight
2.2 oz.
Features
- Intelligently stops DC voltage from the mains to eliminate transformer hum
- Retains EMI shielding for uninterrupted signal integrity
- Ensures equipment safety remains unaffected
- Compact size for universal application without blocking other connections
- Features exclusive iFi ZERO DC Block technology
- Blocks incoming DC up to 1,200mV
- Equipped with hospital-grade IEC connectors
- Built with high-performance glass passivated semiconductor and fireproof polymers
What customers say
Customers consistently express high satisfaction with the iFi DC Blocker, primarily praising its exceptional quality and significant value. Users frequently report a dramatic reduction or complete elimination of transformer hum and mains noise, leading to a noticeably cleaner and quieter audio presentation. This effectiveness is a recurring theme, with many considering it an essential upgrade for their audio systems. The product is seen as a a reliable solution that delivers on its promise, enhancing the overall listening experience without fuss. Its ability to improve sound clarity for a reasonable investment makes it a highly regarded component.
Know before you buy
If your amplifier produces a mechanical buzzing or humming sound directly from the chassis—rather than through your speakers—it is likely caused by DC offset on your AC power line. The DC Blocker is specifically designed to resolve this issue by preventing that DC voltage from saturating your transformer.
The DC Blocker is rated for a continuous current of 4A and supports a maximum power of 440W at 110V or 880W at 220V. As long as your amplifier stays within these power specifications, it will not restrict the performance or dynamics of your equipment.
It is designed for use with components that have an IEC power inlet, such as amplifiers, preamplifiers, and power conditioners. However, it is intended specifically to address transformer hum, so it is most effective for devices with large toroidal transformers.
No, the device is engineered to maintain the EMI shielding integrity of your power setup. It acts as a transparent pass-through for your power signal while filtering out the unwanted DC voltage.
Yes, it is built with fireproof polymers and high-performance semiconductors, meeting hospital-grade safety standards. It is designed for reliable, long-term operation in high-end audio systems.
The DC Blocker is designed with a slim profile to ensure it does not obstruct adjacent outlets or power ports. Its compact dimensions allow it to fit easily behind most audio components without requiring extra space.
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