Electronics-Lab.com Blog

coolarduino.wordpress.com writes:

O’K, after having some fun with stereo version of the VU meter I described in my previous blog-post, now it’s time to do a serious stuff. Studio grade VU meter !!! 24 steps, equally spaced every 3 dB, covering Extra wide Dynamic Range from -63 up to +6 dB. Single (mono) channel this time, no messing around, absolute precision at the stake. Plus, it keeps absolutely Top-Flat linear frequency response from 40 Hz up to 20 kHz(*).

Audio VU meter with extra wide Dynamic Range 69 dB - [Link]

Texas Instruments has introduced three analog-input class-D stereo amplifiers for use in soundbars, after-market automotive solutions, portable audio docks, and LCD televisions. The TPA3116D2, TPA3118D2 and TPA3130D2 feature the industry’s highest programmable switching rate and widest power supply range, enabling audio output that is both high quality and highly efficient. The devices are pin-to-pin and software compatible and can support a single-layer printed circuit board (PCB), enabling cost savings by allowing designers to reuse a single layout for multiple designs. [via]

Class-D Audio Amplifiers with Wide Supply Range and High Switching Rates - [Link]

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]

Mikko writes:

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.

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]