shared wiring

This is an audio effect circuit that give extra oscillation to your guitar, percussive, or semi percussive instruments, you can call it a funk box. This  guitar effect circuit is basically a damped oscillator that is set slightly below its critical oscillation point.  

The oscillator part is constructed by feeding back the output signal through a bandpass circuit, with the center frequency is adjusted by potentiometer R7 to add an extra “twang” , adjustable from low to high pitched timbre. Potentiometer R4 is used to adjust the gain of the oscillator, should be set to damp the oscillation at the desired decay time.  

To adjust it, turn the knob slowly until a steady oscillation occurs, and turn back slightly just before it happens (the oscillation should ceases slowly). Here is the schematic diagram of the circuit.

 

This automobile stereo amplifier project is a class AB audio power amplifier using the Hitachi HA13118 module. It not only can be used in automobile application but also in any transportable or home amplifier process. It is simple to construct & has a maximum of outside parts. The module has a high power output from a low voltage supply using the bridge tied load system, & a high gain of 55dB.

This project will be useful in applications where the input signal is a low level, without requiring the use of a separate pre-amplifier. This IC module has a built in surge protection circuit, thermal shutdown circuit, ground fault protection circuit & power supply fault protection circuit making it reliable.

The Specifications of this project 
D.C. Input : 8 – 18V at 1-2 A

Power output : 18W maximum, 4 ohm load, 18V DC supply

S/N ratio : > 70 dB

THD : < 0.2% @ 1W

Freq. Response : ~ 30 Hz to 30 kHz, –3 dB

Input level : < 25 mV, for full output (G > 50dB)

Input Impedance : ~ 30 k ohm

The supply voltage necessary for this project is 8 -18V DC, at least one to two Amps. Maximum output power will only be obtained with a power supply of 18V at greater than two A, using a four ohm speaker. The power supply ought to be well filtered to reduce mains hum, a regulated supply will reduce noise even further. Additional filtering is unnecessary if operating from a battery supply.

Circuit Diagram Description

Most of the circuitry is contained within the amplifier module. C10 is the input coupling capacitor and blocks DC from the input. C11 bypasses any RF which may be present at the input. C1 & C2 provide an AC ground for the inverting inputs of the IC. R1/C7 and R2/C8 provide a high frequency load for stability with difficult speakers. C five & C six provide bootstrap feedback for the IC. C9 & C12 provide power supply filtering.

An externally mounted logarithmic potentiometer of between 10k ohm and 50k ohm, is used depending on the desired input impedance. The impedance ought to be keep as high as feasible for a guitar amp, unless using a separate pre-amp. Make sure-that the heat sink is mounted to the module.

The prototype had an overall gain of 0.5 dB when the expander input was connected directly to the compressor output. To allow acceptance of high input levels, R13, R14, and the compressor input resistance form a 10:1 attenuator. At the expander input, R5 and the expander input impedance of about 3 kfl form a potential divider. If the compander is to be used with smaller signals, the attenuation can be reduced as appropriate. If the input level lies below 100 mV, R5, R13 and R14 can be omitted. The compander covers the frequency range of 20 Hz to 20 kHz, the overall distortion is less than 1%, and the signal-to-noise ratio is about 80 dB.