simple bass booster circuit diagram

This bass boost diagram is easy to build and work well, I made it because people asked me the schematic diagram of bass boost diagram on my youtube channel.

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 = + 15dB(gain = 6 times)@159 Hz and + 17.84dB(gain = 7.8 times)@80 Hz and then + 19.39dB(gain = 9.33 times)@40 Hz good for very small speaker, 2 way car speaker 

0.2 uf = + 15dB(gain = 6 times)@80 Hz  good for small speaker

0.4uf = +15dB(gain = 6 times)@40 Hz   good for someone that love deep bass boost and big speaker

See testing video