Dilshan R Jayakody’s Web Log

This is 4-way stereo unbalanced distribution amplifier (DA), which can be used to distribute (or split) input audio signal to 4 isolated audio devices. Distribution amplifier in this article is based on commonly available TL072 and TL074 low noise operational amplifier ICs and 7812/7912 voltage regulator ICs. To drive this system, 12V-0-12V or 15V-0-15V 1000mA center tapped step-down transformer is required. Also note that the operational amplifiers used this circuit can be replaced with identical high-quality versions like OPA4134, OPA2134, etc. In our prototype, we use the TL07x series because of its availability and lower price. PCB design of stereo DA project To avoid any interference it is highly advisable to construct this circuit on PCB and also use double core screened wires for all external audio connections. Schematic, PCB and "EAGLE project files" of this project are available to download at google drive .

Nowadays DSL splitter is a common unit in telecommunication and it is used by most of the ADSL users to obtain the maximum performance of the connectivity. Technically DSL splitter is an analog LPF (low pass filter) which is used to prevent interferences between analog telephone device(s) and DSL support units. In this project we describe how to build miniature ADSL splitter at home with grater simplicity and with minimum amount of cost. To build this unit user need to use few generic components which include pairs of 330µH inductors and 1R resistors, 0.0033MFD capacitor and three units of RJ11 PCB connectors. We successfully test this splitter with our local ADSL connection and it gives equal performance of commercial DSL splitter. The complete schematic and PCB diagram (Eagle) of this ADSL splitter is available to download at google drive