Vinod.S @ blog.vinu.co.in writes:
This is my first AVR based hobby project and the most successful one compared to my all previous stuff. I am 100% satisfied with this work.. Few months ago, I tried to make a wav player using a PIC16F877A. It worked anyway, but the audio quality was not so good for higher sampling rate because that chip doens’t have enough ram and thus I couldn’t implement a good data buffer. But when I bought an atmega32 microcontroller, the first thing came to my mind is to make a good wav player…Now, I have completed my work and the audio quality is really amazing…
NOW I can say that, my wav player IS ABLE TO PLAY 8 BIT MONO/STEREO with maximum bitrate of 1300kbps for mono and 1600kbps for stereo … ie it can play an 8 bit mono wav of sampling frequency upto 160KHz and stereo upto 96KHz without any noise or trouble!!!!! (at OSC 16.450MHz).
Stereo MMC WAV player using ATMEGA32 - [Link]
In this article I will discuss my own experiences about designing a USB sound card, which is the USBDAC. DAC is an acronym for Digital-to-Analog Converter because in a sound card, digital data representing the sound is converted into analog voltage that moves the speaker cone.
My device is loosely based on the PCM2706 reference design. I will not go through the tecnical details but instead concentrate on my own experiences in the design of the device. This is to keep people not familiar with electronics, as well as newcomers to electronics design, interested. You will see that one working product is the result of many failed prototypes.
Designing a USB sound card - [Link]
Amplifier with TDA7294 of the ST microelectronics, you can get power up to 100W in a single chip.
TDA7294 Power Audio Amplifier 80W - [Link]
SweepGen turns a PC into an Audio Oscillator and Sweep Generator which can be used for testing audio or educational purposes. In conjunction with audio test instruments, you can make frequency response plots. SweepGen uses the sound card in your PC to produce sine waves that are mathematically correct almost to CD quality, indeed it’s more likely that the quality of your PC sound card will be the limiting factor rather than the code in SweepGen.
SweepGen – Turn your PC into an Audio Oscillator - [Link]
This circuit is a complete 2.1 amplifier for two satellite speakers and one subwoofer.
TDA2030 Audio Amplifier with 2.1 – 3 x 18 Watt – Subwoofer - [Link]
This is a PDF in English published in 1947 and features 45 complete schemes of tube amps, including diagram drawing material list and description of operation. Ideal for anyone interested in old amplifiers (Vintage) and the supporters as well as a modern valve amplifier. The power of the circuits presented in the book ranges from 1 to 75 Watts.
Practical Amplifier Diagrams – Tubes Audio Power Amplifiers - [Link]
Company Hammond Manufacturing is probably familiar to you in context with high quality aluminium and plastic enclosures. But Hammond Manufacturing also produces a wide range of audio transformers, chokes and lamp transformers.
Audio transformers are mainly known to those, who work with professional sound equipment, microphones and high-end lamp amplifiers. A main function of transformers in audio devices is above all impedance matching. Various audio signal sources, like for example microphones, have an impedance different from impedance required for further signal transmission. Naturally, without impedance conversion, a direct connection into a transmission chain would cause a significant change of signal level, moreover frequency dependent, lower resistance to interference, or an overload of an end stage (at a lamp amplifier). At the same time transformers provide a galvanic disjunction, thus their usage is often convenient also from safety reasons.
Advantages / Features:
- top quality
- balanced frequency response
- low insertion loss
Hammond Manufacturing has long-term experience with a development and production of audio transformers. In a production portfolio we can find various series, from simple ones up to top wideband series, like for example the 850A series with a frequency response +/- 0.5 dB from 20 Hz to 20 KHz. Another group of components consist of lamp transformers. Here we can find output transformers, supply transformers, chokes, but even drivers and also many construction components.
Top quality Hammond audio transformers - [Link]
Hack a Week’s new project this week is a single NPN transistor audio preamp – [via]
Here’s a great little project that goes well with the LM386 audio amp. It’s a good first time transistor project because it’s simple and demonstrates the common emitter class A amplifier circuit with only six components in the signal path.
The single NPN transistor audio preamp - [Link]
On my desktop PC I have a speakers and a headphones. Usually I use headphones, but when I need to switch to speakers I need to physically plug in speakers instead of headphones to my PC’s soundcard. I wanted to solve this problem for a long time, but never get around of that until recently I saw this posted on Hackaday.
And so I’ve decided to build my own really simple audio multiplexer.
USB Audio Multiplexer - [Link]
Atmel launches digital audio development system – [via]
Atmel Corporation has announced a complete hardware and firmware digital audio solution aimed at simplifying the design of digital audio equipment for consumer, automotive and industrial applications. Based on the Atmel’s AVR UC3 microcontrollers, the Digital Audio Platform is specifically tailored for audio applications such as USB docking stations for smartphones and media players.
The platform comprises dedicated microcontrollers, evaluation kits and firmware IP. The firmware IP includes control and streaming interfaces for popular smartphones and portable media players as well as MP3, WMA and AAC decoders, USB protocol stacks, and a complete file system to allow designers to utilize mass storage devices such as USB flash disks and SD cards. The Digital Audio Platform is ideal for applications including docking stations, USB mass storage, SD card playback, car stereos, USB speakers, microphones, and various voice and music equipment.
Atmel launches digital audio development system - [Link]