Tremolo Effect Circuit for Electric Guitar

 

Tremolo circuit is a kind of sound effect. We can see this type of effect is applied  in guitar effect pedals.  Tremolo effect is produced if we modulate the amplitude of an audio signal. The shape of modulating signal can vary from square wave, sawtooth wave, or sine wave. When we use a square wave, then the effect produce a knocking-like sound which might be perceived like a percussive instrument.

Stereo Digital Volume Control Circuit

Here is the circuit diagram of stereo digital volume control. This circuit could possibly be applied for upgrading your manual volume management within a stereo amplifier circuit. In this particular circuit, push-to-on switch S1 controls the forward (volume enhance) operation of the two channels while a identical switch S2 controls reverse (volume reduce) operation of the two channels. In this digital volume control circuit, the IC1 timer 555 is set up as an astable flip-flop to deliver low-frequency pulses to up/down clock input pins of pre-setable up/down counter 74LS193 (IC2) through push-to-on switches S1 and S2. To adjust the pulse width of pulses from IC1, you may possibly replace the timing resistor R1 by using a variable resistor. This is the figure of the circuit;

Operation of switch S1 (up) triggers the binary output to increment while operation of S2 (down) triggers the binary output to decrement. The highest count being 15 (all outputs logic 1) and lowest count being 0 (all outputs logic 0), it outcomes in highest and lowest volume respectively. The active high outputs A, B, C and D of the counter are utilized for controlling two quad bi-polar analogue switches in each of the two CD4066 ICs (IC3 and IC4). The two of the output bits, when high, short a part of the resistor network comprising series resistors R6 thru R9 for one channel and R10 thru R13 for the other channel, and thus manage the output of the audio signals being fed towards the inputs of stereo amplifier circuit module. Push-to-on switch S3 is utilized for resetting the output of counter to 0000, and thus turning the volume of both of those channels to the lowest level.

Baxandall Tone Control Circuits Using Two Transistor

This is design circuit of tone control circuit that is 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. This circuit is built by two transistors. This is the figure of the schematic.


The transistors can be substituted by any general audio transistors with small current gain more than 100 (BC547, 2N3904, and many more). The supply voltage for this circuit is 9-15V DC. The components that is used is low cost and can buy in component electronics store.

Dual Channel Digital Volume Control Circuit

This is a design for digital volume control. This circuit could be used for replacing your manual volume control in a stereo amplifier. This circuit is built from 7555, 74193 and dual 4066 IC. This circuit is a dual channel volume control. This is the figure of the circuit.


IC1 timer 555 is configured as an un-stable flip-flop to provide low-frequency pulses to up/down clock input pins of pre-stable up/down counter 74LS193 (IC2) via push-to-on switches S1 and S2. To vary the pulse width of pulses from IC1, one may replace timing resistor R1 with a variable resistor. Operation of switch S1 (up) causes the binary output to increment while operation of S2 (down) causes the binary output to decrement. The active high outputs A, B, C and D of the counter are used for controlling two quad bi-polar analogue switches in each of the two CD4066 ICs (IC3 and IC4). Each of the output bits, when high, short a part of the resistor network comprising series resistors R6 through R9 for one channel and R10 through R13 for the other channel, and thereby control the output of the audio signals being fed to the inputs of stereo amplifier.

Two transistor tone controller

This is a simple design for tone control, but in this circuit it built by two transistors. The transistor that can be used is BC109C. This is the figure of the ton control circuit.

The operation of the circuit is the transistor Q1 is wired an emitter follower to provide sufficient current gain and input impedance. The second transistor is used to voltage amplify the signal in. The network of resistance and capacitors connected between emitter of Q1 and base of Q2 is used to control the tone. Variation in the value of these components varies the audio response of the system. This circuit can provide a maximum attenuation and boost of 10decibel on 10 KHz and 60 Hz frequency ranges. The input and output must be connected with respect the ground. POT R5 can be used to control bass. POT R8 can be used to control treble.

Stereo Line Driver Circuit Using Transistor

This is the schematic diagram of a low cost stereo line driver. The circuit is based only two transistors and few passive components. This is the figure of the circuit.


The description work of the circuit is each BC 109C transistor is wired as an emitter follower for driving each channel. The voltage gain of the emitter follower is unity, but it has a high current gain and low output impedance, ideal for driving long cables. The output impedance is around 16 Ohms at 1KHz.Since voltage gain is unity power amplifiers must be used at the listening end in order to drive loud speakers. The circuit can be powered from a 12V battery or 12V DC power supply. A power amplifier is needed at the listening end because the emitter follower has only unity voltage gain. The inputs and outputs must be connected with respect to ground as shown in circuit.