Archive for the ‘Audio’ Category
Second Order Butterworth Low-Pass Filter

A second order filters can be constructed using LC (inductor-capacitor) passive circuits, and they have been implemented for radio frequency for cheap and simplicity. For audio frequency range, unfortunately the size for the inductor and capacitor become too large, space consuming, and the most important is they’re really expensive. Because of this, active filter is …[Read More]
Voltage-Controlled Stereo Volume Control Using LM13600 OTA

What we can do with a stereo voltage-controlled volume control? There so many things, we can control our audio using a DAC which is controlled by a microcontroller, or we can use mono potentiometer with RC filter to minimize the scratched sound produced by a dirty potentiometer (I see this method in one of SONY …[Read More]

Operational amplifiers for tone control circuit application require high slew rate, wide bandwidth, high input impedance, and high output current characteristics, and CA3140 is suitable for this purpose. Look at the following tone control circuit’s schematic diagram for the design. The tone control circuit in the figure above use a very popular Baxandall tone control …[Read More]
Baxandall Tone Control Using Two Transistors

This tone control circuit use very popular Baxandall configuration, a simple circuit configuration that provides boost and cut control in continuous manner. This circuit is very cheap to build, and it’s commonly implemented in commercial product. Here is the circuit’s schematic diagram: The transistors can be substituted by any general audio transistors with small current …[Read More]
Simple 10 Watts Audio Power Amplifier Using Transistors

This audio power amplifier circuit is simple and robust, and use discrete component available on many electronic part stores. The final transistors use 2N3055 and MJE2055. Here is the circuit’s schematic diagram: The MJE2055 is an npn transistor, but the configuration with TIP42A make the whole combination of TIP42A and MJE2055 are seen as pnp …[Read More]
Voice Operated Switch (VOX) Circuit Using LM346 For Public Address Amplifier System

Feedback in public address amplifier is something that should be avoided. The ideal solution is by adjusting the microphone and the speaker position, but it’s not always possible in many situation. Using frequency shifter to change the output frequency 10Hz lower than the input frequency can solve the problem, but it’s too expensive for …
Carlin Fuzz Compressor: Two Guitar Effects in One Box

It’s easier to manage if we put the distortion and the compressor effect in one box. This Carlin fuzz compressor use unique method to give sustain and distortion effect in mixed circuit. Seem that the circuit do the dynamic compression and distortion in a single negative feedback loop. Here is the circuit schematic diagram: The …[Read More]
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