In supply section after bridge rectifier and smoothing capacitor is used common voltage regulator LM317, which has with R1 and R2 adjusted output voltage about 8V. Supply line goes through inductor to DAC chip for theoretically lower HF interference which goes on the power lines. DACs have current outputs which are converted to the voltage outputs with the aid of resistors R4 and R5.
Click here to download the full size of the above Circuit.
Sometimes is used circuit with operational amplifiers combined with low-pass filter which is much complicated and can introduce distortion in to the sound. Low-pass filter which is used for removing sampling frequency unfortunately introduce distortion on high frequencies. Sound is then more flat. Because DAC doesn`t have symmetrical power supply, that we must use capacitors in series with the outputs. It`s desirable to use high quality capacitors with sufficient capacity. It`s not recommended to use electrolytic capacitor. I used foil capacitors with 10uF value which are connected between outputs and output connector. They are placed out of board and they are not drawed in a schematics diagram. Output must not be too much loaded and should be connected to input of preamplifier or power amplifier with input impedance at least 10 kiloohms. It`s possible to have separated supply for DAC from independent winding of power transformer for better isolation between S/PDIF decoder and dac with changing voltage. Voltage regulator and DACs must be cooled with a small heatsink! Transformer must be dimensed for current 0. 5A. We are placing components on board from smaller to bigger. We begin with SMD components and next with normal parts. We must mount small heat-sink on the DACs otherwise they overheats and can burns (my own experience). I attached heatsink with two small springs hooked to four pins soldered to the board. For I2S...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
characters left: