Audio category

Hi-Fi Stereo Headphone Amplifier using LME49600

This project is the ideal solution for high output, high performance high fidelity stereo head phone amplifier. The project consists of Op-Amp LME498720 and LME49600 as output driver. The LME49600 is able to drive 32Ω headphones to a dissipation of greater than 500mW at 0.00003% THD+N while operating on ±12V power supply voltages.  The LME49600 is a high performance, low distortion high fidelity 250mA audio buffer. The LME49600 is designed for a wide range of applications and is fully protected through internal current limit and thermal shutdown.

Hi-Fi Stereo Headphone Amplifier using LME49600 – [Link]

Design of a Korg Nutube Amplifier

Karlwoodward @ www.rs-online.com/designspark is in the process of designing a “guitar pedal” for amplification and distortion using the Korg Nutube we featured earlier. The Part 1 of a series of articles goes through the basic aspects of tubes and valves, the pros and cons on using a Nutube valve as well as discussing about low gain and high source impedance. In Part 2 of the series he goes deeper by building a working prototype and making some measurements.

Acusis – array microphone for speech recognition

An echo-canceling, far-field, linear array microphone for speech recognition and voice communications.

Acusis is a simple-to-use, complete solution for improving the audio quality for your speech recognition or video communications project. It solves multiple audio issues in a single device that mounts on a TV or monitor and hooks up to your Mac, PC, or single-board computer with standard USB protocols.

Acusis – array microphone for speech recognition – [Link]

Nutube – low power vaccum tube

A new vacuum tube which puts vacuum fluorescent display technology to practical use is in distribution from RS Components.

Nutube, similar to a conventional vacuum tube, has an anode grid filament structure, and operates exactly as a triode vacuum tube. Also similar to a vacuum tube, it creates the same characteristic rich overtones. By applying their vacuum fluorescent display technology, Noritake Itron Corp., a Noritake Co. Ltd affiliated company, have devised a structure which achieves substantial power saving, miniaturization, and quality improvements when compared with a conventional vacuum tube.

Nutube – low power vaccum tube – [Link]

Meet Spritzer, Sony New Arduino

Sony has recently launched one of its new products, Spritzer! Spritzer is an Arduino-compatible board for IoT applications that has built-in GPS, audio codec, and low power consumption.

While it is Arduino-compatible, the board allows any developer to easily start app development using the free Arduino IDE and an ordinary USB cable. In fact, the board features a processing chip with a unique combination of low power consumption and a rapid clock speed of 156MHz. Thus, it is extremely versatile and it can be deployed for a vast range of use cases.

For the first time, the company demonstrated the board at Tokyo Maker Faire last month with a drone utilizing the GPS and the 6-axis sensor support, a smart speaker utilizing the audio functions, a self-driving line-tracing miniature car, and a low-power smart sensing IoT camera using the camera interface of Spritzer.

Sony Spritzer specifications

  • MCU – Sony CDX5602 ARM Cortex-M4F ×6 micro-controller clocked at up to 156 MHz with 1.5MB SRAM
  • Storage – 8MB Flash Memory, micro SD card
  • GNSS – GPS, GLONASS, supported
  • Audio – 3.5mm audio jack
  • Expansion I/Os
    • Digital I/O Pins – SPI, I2C, UART, PWM ×4 (3.3V)
    • Analog Pins – 6ch (3.3V range)
    • Audio I/O – 8ch Digital MICs or 4ch Analog MICs, Stereo Speaker, I2S, CXD5247 audio codec with 192 kHz/24bit High-Resolution audio
    • 2x camera interfaces
  • USB – 1x micro USB port for programming
Spritzer Block Diagram

“You’ll have to connect external module to get Bluetooth, WiFi, and LTE, a display up to 360×240 resolution can be used via SPI, all sort of sensors can be connected via the expansion header, the board is suitable for microphone arrays, and it can be powered by batteries thanks to a charger circuit and fuel gauge inside CXD5247 audio codec / PMU chip.” – CNXSoft

More details about the board will be available by 2018. Until then, check this Japanese official page about Spritzer, or this translated page.

Tune Your String Instruments Perfectly With Roadie Tuner

Roadie Tuner is a dream come true for guitarists! The automatic ring tuner, that is quick, easy to use, and three times more accurate than the human ear, is dedicated to beginner guitarists who are almost always frustrated with not knowing how to tune their guitar. This ultimate musician’s tool works on all string instrument to fine tune them in seconds, including bass guitars.

Roadie Tuner pairs with a free app on your smartphone, iPod or tablet through Bluetooth 4.0 smart. All the audio processing happens on the smartphone which sends tuning commands to Roadie. You can choose from a list of alternate tunings or you can easily create your own.

You can set up a profile for your instrument in Roadie Tuner app and it will track its maintenance history. Thus, it will inform you of the quality of your strings and recommend restringing as soon as the tone quality deteriorates.

Roadie tuner team had just launched their second version of this amazing product, Roadie 2. The new about this tuner the fact that it is  fully standalone and uses vibration detection to tune in even the noisiest of environments. Thus, no need to be paired with a mobile app anymore to tune your instruments.

Below are Roadie 2 technical specifications:

  • Metallic gearbox: Built with a 380:1 gear ratio motor that insures Roadie 2 will turn those rusty pegs for you. The motor can turn in micro-movements to achieve unparalleled precision.
  • Battery:Powered by a rechargeable Lithium Ion battery (included). Lasts 1 month on a single charge. Includes a battery indicator to show you how much juice is left.
  • USB-C: With a charging cable included.
  • Built-in user interface: For easy selection of instruments and tunings.
  • Bluetooth 4.0 low energy
  • Haptic feedback: When a string is in tune, Roadie will give you a little shake to move on to the next string.
  • OLED screen Invisible when off, lights up beautifully as soon as you turn Roadie 2 on.
  • Knob interface: Intuitive and fast to scroll through your instruments and tunings.
  • Weight: Product weight: 3.2 ounces. Shipping weight: 9.9 ounces.
  • Product dimensions: 3.4 x 3.0 x 1.0 inches.
  • Material / Color:Plastic / Black.

“I think the concept is fantastic and I would be thrilled to have one of these because I actually play twelve string guitars. You don’t know how bloody difficult it is to keep a twelve string in tune” – Spike Edney, Queen

More details about extra features within the Roadie Tuner app, the product versions and more are available at the Kickstarter campaign the team had launched 2 days ago. Within only 3 hours, the campaign had achieved its goal and it is already 300% funded. Early bird offers still has 8 hours to go, you can pre-order your own Roadie for $79! Also check out the official website for more information.

Tiny Professional Microphone Preamplifier

The board has been design around INA217 low distortion, low noise instrumentation amplifier. The INA217 is ideal for low-level audio signals such as balanced low-impedance microphones. Many industrial, instrumentation, and medical applications also benefit from its low noise and wide bandwidth. Unique distortion cancellation circuitry reduces distortion to extremely low levels, even in high gain. The INA217 provides near-theoretical noise performance for 200Ω source impedance. The INA217 features differential input, low noise, and low distortion that provides superior performance in professional microphone amplifier applications. An OPA2137 op-amp used as a feedback to eliminate the offset voltage. Phantom power is not part of the circuit its just for reference.

Features

  • Supply Dual +/-15V DC
  • Output Unbalance Single Ended
  • PR1 Gain Adjust G=1+10000/Rg PR1

Tiny Professional Microphone Preamplifier – [Link]

High Performance Stereo Audio Amplifier using LM3886

The LM3886 is a high-performance audio power amplifier capable of delivering 68W of continuous average power to a 4Ω load and 38W into 8Ω with 0.1% THD+N from 20Hz–20kHz.

The performance of the LM3886, utilizing its Self Peak Instantaneous Temperature (°Ke) (SPiKe) protection circuitry, puts it in a class above discrete and hybrid amplifiers by providing an inherently, dynamically protected Safe Operating Area (SOA). SPiKe protection means that these parts are completely safeguarded at the output against overvoltage, under voltage, overloads, including shorts to the supplies, thermal runaway, and instantaneous temperature peaks.

The LM3886 maintains an excellent signal-to-noise ratio of greater than 92dB with a typical low noise floor of 2.0µV. It exhibits extremely low THD+N values of 0.03% at the rated output into the rated load over the audio spectrum, and provides excellent linearity with an IMD (SMPTE) typical rating of 0.004%.

Note : Amplifier Requires a Large Size Heat sink

High Performance Stereo Audio Amplifier using LM3886 – [Link]

The SilentSwitcher, A Quiet Mains-free Power Supply

Audio projects become smaller over time with the rapid advancement of technology. A traditional power supply is still considered large compared to audio projects size constraints and it may not fit such delicate applications that need to deliver a good sound with zero noise.

Jan Didden, audio specialist who is known for his own publications Linear Audio, has came up with a new idea that can help in perfecting audio projects. The SilentSwitcher is a 55 x 31 mm special power supply module designed to supply clean power to high-end analog and digital audio circuits.

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“One goal of this power supply that it doesn’t need to connect to the mains, you can use it with a USB charger or with a power bank… All problems with ground loops and mains born noise are not existing”- Jan Didden, the designer of The SilentSwitcher

The SilentSwitcher uses a combination of switching and linear regulators to generate a stable and noise-free supply voltage. The module can be powered from a 5V USB adapter, or from a 5V power bank for complete isolation. It delivers ±150 mA and a choice of 6V, 5V or 3.3V at 0.5 A to benefit most of your applications. The absolute maximum input voltage is 12VDC but in normal operation it is preferable to limit it to 10VDC.

Output specifications:

  • Outputs (analog): +15 and -15 VDC at 150mA* each;
  • Output (6/5/3.3V): selectable 6, 5 or 3.3 VDC at 0.5A*;
  • Output noise (6/5/3.3V): less than 1mV broadband
  • Output impedance (analog): less than 10mΩ (+15V) and 80mΩ (-15V) at 20kHz
  • Output impedance (6/5/3.3V): less than 3mV drop with 100mA current step.

15V output at 150mA are provided thanks to the very low noise linear regulators of Texas Instruments TPS7A47, TPS7A33 that suppress all the noise from the switching regulator by a factor of one thousand even at 1 Megahertz. Such chips have driven zero noise to switcher technology and have shown incredible quiet and low noise performance.

Jan Didden talking about his product

The well designed board will help in keeping all elements quiet and avoiding excess radiation. There are 2- and 3-pin headers on the PCB to connect the load, and a 2-pin header for an On/Off switch. The connection to the 5V source is through a B-type USB connector or a standard 2-pin screw-type connector block. You can mount the PCB on the back of your enclosure with a hole cut out for the USB-B – no further input wiring required.

The SilentSwitcher Connections
The SilentSwitcher Connections

This power supply will be a great companion for your project! No need to think about wiring or transformers, and you won’t face any issues like mains hum or mains earth loops.

The SilentSwitcher is live on a Kickstarter crowdfunding campaign and there are only few hours left to go! You can get your own SilentSwitcher for $59 and you will receive a fully assembled and tested board.

More details are provided at the campaign page and at Linear Audio website.

LTC3623 – Switching regulator doubles as Class-D audio amplifier

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Clemens Valens @ elektormagazine.com discuss about LTC3623 switching regulator which can be used as Class-D Audio Amplifier.

Sure thing, Elektor has published several designs of adjustable power supplies based on switching regulators, so we know that doing this properly in a reproducible way and without making things overly complex requires some serious head scratching. The anxiety may be reduced vastly though by a new adjustable synchronous buck regulator which uses a single resistor to set its output voltage anywhere between 0 and 14.5 volts. Using the device is very simple; you can even use it as an audio amplifier.

LTC3623 – Switching regulator doubles as Class-D audio amplifier – [Link]