DC Blocker

Features ​​​

• Blocks DC offset
• Common Mode filter
• Differential Mode filter
• Overvoltage protection
• Clever indicator for proper mains connection
• Ground-Bridge selector for external 'audio' earth connection
• Silver plated copper wiring with PTFE insulation
• IEC C14 input connector gives the freedom to use preferred power cord

What to expect?

The synergy of blocking DC offset and filter technology guarantees that our DC Blocker effectively resolves the issue of mechanical transformer hum (buzz) caused by a DC component on the mains supply. The integrated mains filter also significantly reduces electrical noise, ensuring your equipment operates at its full potential. Whether using it in a professional studio or at home, our DC Blocker enhances the overall performance of your audio set. The result will be an improvement in dynamics, greater precision, a much better sound image and a lower hum level.

Where to use?

The Essential Audio Tools DC Blocker is essential for any audio system where unwanted DC offset causes transformer saturation and/or electrical noise degrades the sound quality. When using heavy duty mono power amplifiers we strongly advise to use a DC Blocker for each amplifier. Also use high quality (shielded) power cords like our Current Conductor cables to achieve maximum results.

DC offset ​​

The mains supply coming from your wall socket should be a pure AC symmetrical sine wave, but in fact the mains supply is being compromised. DC offset and non-linear distortion are generated by equipment connected to the same power grid, negatively affecting the mains supply. Many appliances connected to the power grid load the AC mains cycle unequally for a period of time. This causes an unequal peak voltage of the negative and positive wave and when the sine wave area is not equal in both phases, a DC component is present.

There are many ways DC offset is generated, with most being totally outside your control. DC offset on the AC mains is transient in nature and occurs more often because the number of equipment using the AC mains cycle unevenly is growing fast (such as electrical vehicle charging poles, solar panel converters and light dimmers).

Transformer hum ​​

An electrical transformer is a passive device which transfers electrical energy between circuits through a magnetic field. Basically a transformer consists of two inductive coils; primary winding and secondary winding. The coils are electrically separated but magnetically linked to each other. Transformer core shapes are generally classified into solenoids and toroids. A toroidal transformer has a donut shaped core. The primary and secondary windings are wrapped around the entire surface of this toroidal core, with an insulating material in between. This design significantly reduces magnetic flux leakage, making a toroidal core ideal for sensitive and critical electronic circuits due to their distinct advantages over traditional square and rectangular transformers.

The benefits also include high efficiency, quiet operation, minimal heat generation and a compact size. Transformers, especially toroids, can not handle the presence of DC offset in the AC mains supply because the donut shaped core has no air gap. Even a small DC offset will give undesirable effects, such as increased core saturation, increased transformer heating, mechanical noise (buzz), reduced power capacity and potential damage to other components. Transformers with a (partially) saturated core will also significantly degrade the sound quality of your audio set.

Filters ​

The Essential Audio Tools DC Blocker is equipped with advanced filtering technology to ensure optimal performance. Its integrated filter features both Common Mode (CM) and Differential Mode (DM) filtering, effectively reducing noise and interference for a clean and realistic audio reproduction.

Common Mode

Common Mode (CM) noise is present equally on both power lines with respect to a common ground. It affects both wires in the same way. ​A Common Mode filter is an electronic filter designed to eliminate CM noise. It typically consists of capacitors to ground and/or inductors wound on a ferrite core, which allows differential signals to pass through while attenuating noise that appears equally on both lines. Common Mode noise is typically radiated EMI from sources such as phones, Wi-Fi, GPS and Bluetooth.

Differential Mode

Differential Mode (DM) noise appears across power supply lines. The noise current flows in the same direction as the power supply current. It is called Differential Mode because the outgoing and return currents are equal and have opposite polarity. A DM filter eliminates oppositely-directed noise that is present on a pair of conductors. It typically consists of capacitors between lines and/or an inductor in series. Differential Mode noise comes from sources such as switching power supplies in home appliances, LED lights and electric motors.

Clever phase indicator

The DC Blocker has a clever way to indicate that it is connected to the mains supply the right way. Two LEDs will show you if the DC Blocker has an input voltage, if earth connection is present and if the mains supply's phase is connected properly. When it is connected the right way, you will see two green lights. If one light is off or one light is red, something is wrong with your connection. Have a look at the image for an explanation of the different indications

Unique Ground-Bridge selector

The DC Blocker, Mains Multiplier 6+ and Mains Multiplier 8+ have a special feature. This unique feature is called a Ground-Bridge. It offers you the option to connect to an external earth instead of the earth from the wall socket which is shared with all other devices in your house. In most cases this external earth is a special copper electrode placed deep into the ground outside your house. This earth pole should have an exclusive connection to your DC Blocker, nothing else should be connected to this special earth pole to keep it clean from interference. With the Ground-Bridge placed between the black and the green connector the DC Blocker is connected to the wall socket earth. With the Ground-Bridge placed between both black connectors you can feed the external earth to the green connector.

Working principle 

A DC blocker is an essential device which blocks direct current (DC) while allowing alternating current (AC) to flow. This functionality is crucial for maintaining the integrity of signals, especially in audio systems, where unwanted DC leads to distortion. The Essential Audio Tools DC Blocker effectively removes DC offset and rebalances the AC mains supply sine wave, without compromising dynamic performance. It's sophisticated, low impedance mains filter significantly reduces electrical noise, providing a clean and realistic audio reproduction. Incorporating our DC Blocker into your setup not only enhances performance but also expands the lifespan of connected equipment.

Specifications

• Rated Voltage: 220-240V~ @50/60Hz
• Protecting: ​Phase-Neutral
• Maximum voltage: 250 Volt
• Maximum peak voltage: 2500 Volt
• Maximum peak current: 4500 Ampere
• Maximum peak energy: 2x65 Joule
• Response time: 25 nanoseconds
• Max. continuous current 6 Ampere
• Dimensions (w/o Bridge) 329(l) x 70(w) x 53.5(h) in mm
• Weight1.1kg
• Output connector Schuko Number of output connectors​ ​1