A couple of years ago I decided I would (eventually) need to replace my decades-old Nakamichi stereo with something more suited to a mobile lifestyle. It was immediately pretty obvious that the Class-D and E switching amplifiers I had researched in the `70s were experiencing a renaissance. Tripath had come and gone, but its excellent chipsets rema
Click here to download the full size of the above Circuit.
ined available from China. ST had a few nice chips, as did National Semi, Texas Instruments and IR. I quickly found that the science developed in the `70s, a deep understanding of the differences between switched amplifiers and linear amplifiers, seems to have been forgotten. Sure, the chipsets are really excellent, but the component selection in the application designs seemed to be pretty woeful. Since most of the new chips have a feedback loop which doesn`t include the output filter circuit, poorly designed filter networks were limiting the performance of most of the amplifier modules commonly available. I have been playing with several chipsets, those which I think have the most potential for value-HiFi, and I am going to use the ST TDA7498 chip to illustrate how not to design a quality audio amplifier, and how inexpensive it can be to design a good one. ST don`t supply boards for the TDA7498, so I bought some assembled PCBs on Ebay from Sure Electronics (for the princely sum of $22)(#AA-AB32165). Although they were advertised as TDA7492 boards, several arrived with TDA7498 on them, but the last one came with a TDA7492. So haggle with the seller a little, if you need to operate above a 24V supply rail. I was able to change the chips, but I needed my special surface mount rework tools. SURE assembles these PCBs identically for both CPUs, except that the fan power supply components are added for the TDA7498 version. I...
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: