This is a bass booster circuit that uses transistors as a base. It is designed to increase the low frequency of audio.
They are cheaper than ICs or normally circuit. Because of use each channel only 2 transistors together with resistor and capacitors approximately ten parts only.
In the circuit, Adjust potentiometer trimmer, 10-50K to turns a level of bass level up and down as you want.
Figure 1 is the circuit diagram on mono or signal channel. But the PCB layout below is stereo or dual-channel. Most people like it.
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I do not like to read a lot of text. You may also same me. So, I keep the shortest explaining you.
Here is the step process:
C1 coupling an input signal into the base circuit of Q1 at pin B.
Both resistor R1 and R2 are biased currents to Q1, for first preamplifier section.
Then, a higher signal comes out of E of Q1. The voltage does not change but higher current. It keeps impedance to low.
To drive RC networks to separate and increase the bass signal to higher from other frequencies.
But the signals come out of the R C networks will be too lower.
So, we need to amplify to more with Q2 and a few parts.
After that, some signals at output goes back as a feedback signal to the R-C network circuit. To boost up a signal again.
Also bass booster circuits below
How to builds
Building this project is easy. Just use a 12V power supply regulator that smooth enough.
It may be connected via R-100 ohms and has C-100uF 16V to ground.
As Figure 2 All resistors in circuit use 0.25 W.
Then, the wiring to a circuit and various components. You can view the example in Figure 2.
But look be carefully for the polarity of electrolytic capacitors, legs of the transistors. Must be correct only!
This circuit requires 12V DC voltage Regulator.
The components List
Q1-Q4: 2SC1815 or 2SC945 or 2SC458, NPN transistors
C1,C6: 10uF 16V
C5: 33uF 16V
C2: 0.033uF 50V
C3: 0.0022uF 50V
0.25W Resistors, 5% Tolerance
R2: 680 ohms
R7, R9, R10: 4.7K
R15: 560 ohms
Other see text.
What is more? Not only that.
Loot at This Active Bass Boost circuit
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