A DI box or Direct Injection box is a very useful piece of equipment used to connect keyboard, guitars and other audio signal source directly to the mixer. DI box function is to convert the unbalanced output of the guitar, keyboards and other musical instrument to balanced output. Connecting an unbalanced output to balanced input of the mixer often led to humming noise which is really unpleasant for ears especially when no one is playing the instrument.
Category: Electronics
Guitar Delay Effects project
The design is pretty simple and easy to build. The main delay effects IC is PT2399 which is a cheap solution compared to using complicated and more expensive BBD IC such as MN3207 and the like. PT2399 is digital echo processing IC capable of producing up to 342mS delay with 1.0% THD. You can further expand this to more than 1 second but with the price of higher harmonic distortion which gives not pleasant sound. The resolution of the ADC of the IC is not disclosed on its datasheet, but it sounded good so I guess it’s around 16bit maybe.
Killing sound system feedback
The biggest problem in PA system that most technician hate most is the mic feedback. Feedback is not that hard to eliminate as long as you know what is the cause. There are several common sources of feedback that I will share to you and simple solutions to kill feedback on your system.
Simple tone control design
Here’s a simple tone control design for your home audio system to boost your BASS and treble for more live sound. The circuit is composed of a transistor amplifier to boost the signal because it will be attenuated by the RC filter circuit.
Clean Power Supply for Audio Application
Building a “hum-free” audio is not easy till you know what you are doing. It is not as easy as connecting wire into where it should be connected. Especially for grounds, if you connected it into wrong point. Noise usually come from ground loops or connecting a very sensitive signal ground line to a high current ground path. In most cases a star connection is very effective in eliminating the noise.
Bluetooth Speaker Project
There are lots of bluetooth speaker on the market today. But if you have an old mini component or a sound system that is still working and sounds good, why won’t you just upgrade it and put a bluetooth functionality? There are lots of audio bluetooth receiver on the market today.
Digital clock project
One of my project: a led watch with 71 SMD LED. The microcontroller is a Microchips PIC16F728 running in 4MHz crystal oscillator and powered by CR2032 battery.