Above scheme diagram is turbo bass circuit that can be used to multiply the low frequency sound signals (bass) on your audio system, it also called “bass booster” circuit. This circuit is an active circuit in which the incoming audio signal from the input will be strengthened in the first op-amp. The second op-amp that will filter out the bass signal to set gains so you can get the power of the bass as you want. The potensiometer is used to adjust the bass enhancement.

This circuit requires 9V symmetrical (dual polarity) power supply which has (+), ground, (-) polarity. Center tap transformer used to build this kind of power supply.

This circuit diagram comes from the bass turbo kit that sold at electronic part stores, so we can be sure that this circuit is work. The components is easily find at electronic part stores in your area.