What is it?

The AAL – Premium DC-Blocker with EMI/RFI Filter is a passive mains conditioning device designed to reduce transformer hum, mechanical vibration and buzzing caused by DC offset on the AC mains while helping suppress electrical interference.

Especially effective with toroidal transformers commonly found in audio amplifiers, DAC power supplies, tube equipment and Hi-Fi systems.

This PREMIUM version combines:

• DC offset filtering to reduce transformer saturation and mechanical hum
• EMI/RFI mains filtering to help reduce high-frequency electrical interference
• Carefully selected audio-grade components and robust safety margins

Designed to operate transparently without affecting dynamics, transient response or musicality.

Typical symptoms solved

• Transformer buzzing or humming noise
• Mechanical vibration from toroidal transformers
• Transformer hum appearing mostly in the evening or at certain times of day
• Equipment sounding quieter on another outlet or electrical circuit
• Noise caused by electrically polluted mains environments

Why did you make it?

Many modern electrical appliances inject asymmetrical loads and high-frequency noise into the mains.

Small DC offsets may saturate transformers and create audible buzz or vibration, while high-frequency electrical interference can affect sensitive audio equipment.

The AAL – Premium DC-Blocker with EMI/RFI Filter was designed to help restore quieter operation and improve listening comfort without affecting dynamics, transient response, tonal balance or musicality.

Typical Applications

• Power amplifiers with toroidal transformers
• Integrated amplifiers
• DAC power supplies
• Tube equipment
• Hi-Fi systems
• Studio equipment
• Sensitive analog audio systems

Particularly useful when:

• Transformer hum increases in the evening
• Equipment becomes quieter on another outlet or electrical circuit
• Toroidal transformers mechanically vibrate or buzz
• Your environment contains switching power supplies, computers or electrically noisy equipment

What makes it special?

Designed for users seeking a cleaner and quieter mains environment for sensitive audio systems.

Fuse value, optional inrush-current limiting (NTC) and protection strategy are individually selected according to the connected equipment.

Integrated EMI/RFI mains filtering helps reduce high-frequency interference without compromising audio performance.

Example:

230V / 2.3A device → fuse and startup configuration selected accordingly.

If unsure, simply provide your equipment power rating or rear-panel specifications.

Carefully selected components

• Audio-conscious component selection
• High-quality safety capacitors and power components
• Premium industrial-grade Schaffner EMI/RFI filter stage
• Robust thermal and electrical margins
• Designed for reliable operation without compromising dynamics or musicalitye

Electrical specifications

• Supported mains input: 220–240V AC, 50/60 Hz
• IEC C14 mains input with integrated fuse protection
• IEC C13 power cable included
• Nominal current: 4.35A
• Suitable for equipment up to approximately 1000 VA (depending on transformer type and startup behavior)
• Integrated DC offset filtering + EMI/RFI filtering

Included

• Ready-to-use AAL – Premium DC-Blocker with EMI/RFI Filter
• IEC C13 mains power cable included
• Fully assembled and individually tested unit

Why this price?

Built using carefully selected high-quality components (Cornell Dubilier, WIMA, Wishay, TDK, SCHAFFNER / TE Connectivity.) chosen for performance, reliability and long-term durability.

All parts are sourced from reputable suppliers to ensure quality and traceability.

Who did it?

Designed, hand-assembled and individually tested in France by AAL — Analog Audio Lab.

Practical electronics designed to solve real-world problems.

analog.audio.lab@gmail.com

Early customer feedback

• “The transformer noise completely disappeared.”
• “Everything works perfectly — I’m delighted.”
• “A real improvement in listening comfort.”
• “Even the transformer mechanical hum is gone.”
• “The filter genuinely brings considerable value to the sound.”
• “The electronics perform exceptionally well.”
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