Simple Mic Pre-Amp based LM358

Here the simple mic pre-amp circuit design based on single IC LM358. The circuit is very simple, inexpensive and easy to built. This mic pre-amplifier circuit operated with 9V DC voltage, you may use 9V battery for this circuit. Component Parts List: R1, R3, R4 = 10K R2 = 1K R5 = 100K-1M Potensiometer C1… Read More »

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 »

Passive Surround

This is the scheme diagram of passive surround circuit. Passive surround doesn’t need any active components and power supply to make the circuit works. The circuit just need the combination of resistors and electrolytic capacitors. Circuit Notes: This passive surround circuit MUST be connected after power amplifier module. Use full range type of loudspeaker. Do… Read More »

15W FM Transmitter using BLY88C

This is long range FM transmitter with transmision power output is up to 15W. This 15W FM transmitter use power transistor BLY88C as the main transmitter amplifier. Building a good FM transmitter(88-110Mhz) begins with getting a good schematic. You don’t have to understand the precise working of the transmitter to build it. But some basic… 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: