Tag Archives: audio

App note: WM9712 Jack plug auto-detection, hookswitch detection and microphone headset detection

via Dangerous Prototypes

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App note on Cirrus Logic’s WM9712 jack plug auto-detection by monitoring the connected headphone resistance. Link here (PDF)

This application note describes two operations associated with using headset. The first is the facility to automatically switch between a mono ear speaker and stereo headphones for use in a Smartphone, PDA etc. The second operation is a method which can be used to detect if stereo headphones have been attached or if a mono headset with microphone has been attached.

flip-flop/BCF project

via Dangerous Prototypes

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Ray over at the diyAudio forum has been working on his flip-flop/BCF project:

I’ve just finished a project to roll up the developments into a more ‘finished’ build, feeding the balanced outputs from the flip-flop board into a Broskie BCF buffer stage. I’m using Nicks MJ Statistical Regulator for the B+ and one of Andrew’s indirect filament supplies

Project info at diyAudio forum.

NS1 Nanosynth the hackable analog synthesizer is back!

via Arduino Blog

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We’ve been playing with NS1 Nanosynth in the last few weeks, when it first appeared under our radars on the Christmas’ Gift Guides (while going sold out in few days, after Synthopia blessed it with this interesting review).  It’s a hackable and customizable analog synthesizer coupled with an Arduino Micro platform.

Personally, it was one of my first steps into modular synthesizers. Nice sounds, easy approach. Peter Kirn is perfectly picturing this amazing compromise here!

Synths: they’re fun to tweak and play. Modulars: they’re fun to patch. Arduinos: they’re fun to hack. Small things: they’re fun to carry around.

But how to track patches? How to share sounds with friends? I was playing mainly with my son, and managed to print out a paper sketch depicting all the different pinout of the synth. I wasn’t satisfied with that, I needed more!

I started writing Sound Machines, about new patches, more sounds. It turned out I made a Fritzing part out of the Nanonsynth, and we started sharing each other patches. This repository holds them, and this is a short review of the best. Enjoy!

 

Here you can listen to the envelope Generator (ADSR) in action:

 

Want to add your very own sounds? You can either add it to their repository or comment here!

Replacement LED driver for AN6877

via Dangerous Prototypes

aflevelmeter

Dilshan Jayakody writes:

AN6877 is linear AF level meter IC produced by Panasonic and it is commonly found on many audio equipment. This chip is no longer manufactured by Panasonic and finding replacement chip for AN6877 is also quiet difficult.
The circuit described in this article is design to replace AN6877 base LED drivers and it is based on commonly available components. This replacement LED driver is design using 10, MMBT3904/2N3904 transistors and it can easily modify to get necessary number of outputs.

Project info at Jayakody’s blog and elect.wikispaces.com.

Audio multiplexer with integrated amplifier

via Dangerous Prototypes

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Audio multiplexer with integrated amplifier project by Matt Winslow, built as a capstone project for his masters in EE:

This project is to act as a central hub for switching between audio sources and listening devices. Multiple audio sources can include a phone, computer, TV, etc. The listening devices can include different sets of speakers, headphones, etc. This project aims at reducing the hassle of unplugging and reconfiguring the desired audio source and listening device to just a button press. There is also an integrated volume control knob on the audio mux to conveniently change the gain in the same location as the buttons.

Project info at Winslomb blog.

Check out the video after the break.

Dynamic microphone preamplifier

via Dangerous Prototypes

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Dilshan Jayakody published a new build, a microphone preamplifier:

This is single chip dynamic microphone preamplifier which is design to drive using commonly available 12V single rail power supplies. Preamplifier in this article is build around popular NE5532 dual low noise operational amplifier IC and this preamplifier is specifically constructed to drive professional 600Ω dynamic microphones.
This preamplifier consists with two amplifier stages and initial amplifier is design to get 36dB gain and final preamplifier is used to get 16dB of gain. Preamplifier gain controller is placed in between those two amplifiers and this separation allows reducing clipping in output waveform.

Project info at  Jayakody’s blog and  Elect.wikispaces.com.