Surround Sound Decoder

The following schematic diagram is a small surround sound decoder circuit. You may use this decoder surround sound systems for your home audio system to make the audio system sound more “alive”. Parts List: R1-2-7-8-12-13-18-19-20=47Kohm R3-4-5-6-21-22-34-35=10Kohm R9-10-11-14-15-16-17=15Kohm R=23-24-25-33-36=100ohm R26-27-28-31-32=100Kohm R29-30=5.6Kohm C1-8=47uF 25V C2-7-9-14-23=47nF 100V C3-6=1uF 100V C4-5-10=33pF 100V C11-12-15=10uF 25V C13=82nF C16=18pF 100V C17=100pF mini… Read More »

Dynamic Mic Compressor

The circuit below is a Dynamic Mic Compressor circuit which is simple, easy to built, inexpensive but the results are quite satisfactory. Audio output sounded outstanding. The principle of this circuit is very simple, the first transistor is used as microphone pre-amplifier. Then a second transistor used as a buffer. And the third transistor is… Read More »

Six LED Stereo VU Display

The following image is the scheme diagram of six LED stereo VU display circuit which build using Dot/Bar Display Driver IC LM3915. This VU display should be connected before amplifier module circuit. You may connect this circuit at pre-amp output, tone control input/output or equaliser input/output. This circuit powered with 12V DC supply. About LM3915:… Read More »

Three Stage 9V FM Transmitter

This circuit is a powerful three stage, 9V FM transmitter (Tx) with a range of up to 1 kilometer in the open. It uses an RF transistor in its output stage and two BC547″s for the first two stages. Distance of trans-mission is critically dependent on the operating Conditions (in a building or out on… Read More »

Pre-Amp + Tone Control with TDA1524A

This is a low noise and distortion pre-amplifier and tone control circuit in one module. Using a special IC TDA1524A, this simple circuit is easy to build and will drive most of power amplifier. Schematic diagram: