Active Crossover Circuit based TL074

This is the circuit diagram of active crossover. The crosover circuit built based TL047 and it should be placed before amplifier circuit module.

How it works..?
An audio source, like a mixer, preamp, EQ, or a recorder, is fed towards the input of the active crossover circuit. This signal is either AC or coupling, based on the setting of switch 51, the non-inverting input of buffer amplifier Ul-a, a section of a quad BIFET, low amp TL074 noise produced by Texas Instruments op. This stage has a gain of two, and its output is distributed to both a low pass filter created by R4, R5, C2, C3, and Uld op-amp, along with a high-pass filter created by R6, R7, C4 , C5, and op amp ULC. These are12 dB / octave Butterworth filters. The response of the Butterworth filter was chosen simply because it provides the most effective compromise between the damping and phase.

The values of capacitors and resistors varies based on the selected connection that your device works. The filter outputs are fed to a balancing network created by R8, R9, RIO, R14 and potentiometer RLL balance. When the potentiometer is at its center position, there is certainly a unity gain bandwidths for both high and low filters. The power supply for the electronic circuit is regulated by Crossover R12, RI3, Dl and D2, and decoupled by C6 and C7.

1KHZ Sine Wave Generator Circuit

This circuit generates a great 1KHz sine wave adopting the inverted Wien bridge configuration (C1-R3 & C2-R4). It features a variable output, low distortion and low output impedance in order to obtain excellent overload capability. A small filament bulb ensures a stable long term output amplitude waveform.

Parts List:
R1 = 5K6 - 1/4W
R2 = 1K8 - 1/4W
R3,R4 = 15K - 1/4W
R5 = 500R - 1/2W Trimmer Cermet
R6 = 330R - 1/4W
R7 = 470R - Linear Potentiometer
C1,C2 = 10nF
C3 = 100µF/25V
C4 = 470nF
Q1,Q2 = BC238
LP1 = 12V 40mA Filament Lamp Bulb (See Notes)
J1 = Phono chassis Socket
SW1 = SPST Slider Switch
B1 = 9V PP3


Circuit Notes:

• High gain transistors are preferred for better performance.
• The bulb must be a low current type (12V 40-50mA or 6V 50mA) in order to obtain excellent long term stability and low distortion.
• Using a bulb differing from specifications may require a change of R6 value to 220 or 150 Ohms to ensure proper circuit's oscillation.
• Distortion @ 1V RMS output is 0.15% using a 12V 40mA bulb, raising to 0.5% with a 12V 100mA one.
• Set R5 to read 1V RMS on an Audio Millivoltmeter connected to the output with R7 rotated fully clockwise, or to view a sinewave of 2.828V Peak-to-Peak amplitude on the oscilloscope.
• With C1, C2 = 100nF the frequency generated is 100Hz and with C1, C2 = 1nF frequency is 10KHz but R5 requires adjustment.

1KHZ sine wave generator circuit source: http://www.redcircuits.com/Page13.htm

One Transistor Audio Booster circuit

Here the schematic diagram of Audio Booster circuit based on single Transistor 2N3392

Component Parts:

R1____________47K R2____________470K R3____________10K R4____________560 Ohm R5____________100K Linear pot+switch R6____________270 ohm

Q1____________2N3392 LED1____________red LED C1____________05-.1μF Ceramic C2____________0.1μF Ceramic C3____________33μF/25V

The 2N3392 transistor is a low-noise type in a TO-92 housing and can be replaced by a NTE199 or ECG199. Potentiometer R5 of 100K is a linear type with an on/off switch attached.

The value of C1 may need to be between 0.05μF and 0.1μF (47nF/100nF). Experiment with the value for best performance.