Dilshan R Jayakody’s Web Log

This project introduces a digitally controlled 5.1 channel audio preamplifier system. This amplifier is specifically designed to increase the gain of the multi-channel PC sound cards. The main reason for building this amplifier is the limited gain received from the ASUS Xonar AE sound card with the Creative Inspire T6300 , 5.1 surround speaker system. Before switching to this soundcard, we had a Creative Sound Blaster Z card which provided good audio output with the above-mention speaker system. The key motivation of building this amplifier is to solve these gaining problems. The assembled 5.1 preamplifier PCB. This preamplifier consists of six TL074 / TL072 preamplifier stages and PT2258 electronic volume control. The input stage of this preamplifier consists of six TL074 / TL072 buffer stages. The PIC16F886 microcontroller manages the PT2258 electronic volume control IC. All the volume levels and menu options are displayed on HD44780 , 16x2 character LCD screen . All the ...

Adjustable dual-rail power supply is an essential utility for analog electronic experiments. In this post we illustrate extremely simple, adjustable dual-rail power supply using LM317 and LM337 voltage regulators ICs. This PSU delivers 2A ±1.35V to ±18.5V output and thanks to 3 turn linear potentiometers output can be adjustable up to 2nd decimal point. Wiring diagram of dual-rail PSU The PCB of the PSU is simple to design and compact (65mm × 50mm). Both LM317 and LM337 need at least 60mm × 55mm or larger heat sinks (and both of these heat sinks need to be electrically isolated). The PCB and schematic of this PSU is available to download at here .