amplifier circuit audio amplifier circuit diagram audio amplifier wiring diagram simple bass booster circuit diagram
The circuit has 9 dB gain@40 Hz that mean you will get good bass performance even you play music to a small speaker.
Why this circuit doesn't look like circuits on the internet?
Almost every circuit on the internet uses R/C filter between pre-amp and power amp stage to bypass high frequency to a ground and that seems audio signal being amplified and bypass to ground. I think it wastes pre-amplifier gain, the more gain preamp stage the more distortion to the audio signal, so I use a capacitor to send more negative feedback to pre-amp negative input when the frequency higher than cut-off frequency, capacitor impedance(resistance) higher when frequency lower and that make negative feedback decrease when frequency lower.
An op-amp distortion lowers when negative feedback higher, that mean high-frequency distortion lower when you use this circuit because frequency over cut-off frequency's total harmonic distortion being suppressed around 20 DBs more than normal R/C filter.
The C5 cap can be replaced with MKP type or polystyrene film cap with 1% Precision for the best result.
List of component:
potentiometer = 10 kilo-ohms
IC1 ne5534 (you can use another opamp that pin compatible to the ic)
R1,R6 = 1 kilo-ohms
R2,R3 =10 kilo-ohms
R4,R5 = 4.7 kilo-ohms
C1,C3 = 2.2 uf 16 volts
C2,C4 = 47 uf 16 volts at least (no more than 100 uf)
C5 = 0.1 uf
C5 value can be change depend on your listening behavior
0.1uf = + 3dB@159 Hz good for very small speaker, 2 way car speaker
0.2 uf = + 3dB@80 Hz good for small speaker
0.4uf = +3dB@40 Hz good for someone that love deep bass boost and big speaker
See testing video