What is the obstacle caused by Noise Noise?

The solution of Noise is a very difficult topic for the client.

  • Types of obstacles due to radio towers and high voltage cables.
  • FM / AM Radio and television interference such as TV.
  • Failure due to radio waves by WiFi equipment etc.
  • we want to alleviate Noise that occurs in combination with Set equipment.
  • we want to reduce Noise generated from the AC adapter body.

We propose the following as a countermeasure against obstacles caused by Noise.

  • Proposal of AC adapter according to the requested specifications.
  • Proposal by adding electromagnetic shield.
  • Adjustment with parts to be adjusted according to Nosie characteristics and addition of parts.
  • Proposal of correspondence by adjustment with set equipment provided by customers.

About noise suppression of AC adapter

How would you like to disable the AC adapter due to radio noise from customers? We have asked a lot of questions, such as:

Even if I say in a word with noise, there are various regulatory requirements such as communication system noise and acoustic system noise.
we would like to mention an example of a special kind of acoustic system noise [Beat Noise] this time.

Beat Noise is noise generated in an oblique striped pattern when receiving an image of analog television signals. (Such as waving noise, disturbing sine wave etc.)
In other words, when connecting more than two, such as a large speaker, a guitar amp, etc. on the stage of a concert, before the sound can be made (at the time of silence), howling such as howling from the speaker etc., kind of noise like tinnitus it is a phenomenon that sound comes out.

In such an event, the noise generated from the power source flows to the speaker, and the noise sound is offensive to the ear. Normally, it is thought that GND of the AC adapter and GND of the signal connection become LOOP connection. Countermeasures against causes of insufficient gain (gain) and interference between carrier waves are often difficult.

Unifive is currently custom developing for customers related to audio equipment, and we adopt the following design improvement method to solve this problem.

① Separate the GND connection between the primary side and the secondary side of the AC adapter



② Ferrite beads are added to the internal ceramic capacitor of the AC adapter

③ Devices to connect Pin of AC adapter internal transformer.

Connection to the transformer core Connection Lead line (black) changed connection from transformer Pin 1 to pin 2.

With the above improvements, we can also compare measured waveform diagrams.

In response to this countermeasure, when the level (peak value) is low with a waveform close to the SIN wave, the low frequency audio noise decreases.



The output specification with the measures as described above becomes 13V / 4A. This is the item you are using for the guitar amp.

UNIFIVE has many transactions with customers related to audio equipment. Therefore, the type of AC adapter varies according to it, according to the design philosophy of sound IEC 60065 safety standards, the improvement method of acoustic noise 6 bB - 12 dB, parts selection use to realize long life, the correspondence of electrostatic discharge, custom UNIFIVE's design forces, such as responding to demands for metal pin corrosion, improving Beat noise, etc., are being taken care of every day.

Acoustic equipment, portable and electronic guiters and amplifiers, dynamics that realize superb performance in every scene, including the elegant form, instruments such as quality, polished ground guitar string percussion instruments and pianos, changing to the digital age to the speakers and others that draw out sounds, etc., the trend is that high-quality sound quality is required and the value-added function of products is also increasing, and also in the design of the power supply, inquiries that we want to match the diversification of needs , Increasing year by year. Especially for Japan's electrical products that require high quality, our company continues to evolve and we are pursuing every day to answer that request.

From now on, with the supervision of new technical standards, we will correspond to the technical standard of IEC 62368 which became one. In addition, the Tokyo Olympic Games held in 2020, infrastructure development (station, ward office, library, hospital etc) related periodic exchanges of sound equipment, IOT related (surveillance audio equipment etc.), industry (robot, voice advertisement signboard, etc.) etc. , The variety to be handled is diverse, and UNIFIVE's AC adapter can be used in every situation, so our lineup will be an important thing that will bring a rich life to people's happiness.

UNIFIVE will certainly be able to propose what we can respond to your product requirements, so if you have any request, we would be pleased to heard from you.

You can get the product catalog in PDF.

Product initiatives

Since 1989, UNIFIVE has maintained the quality of their AC power adapters and switching power supplies through a rigorous quality,

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