Stereo Baxandall Tone Control

This Baxandall Tone Control circuit is perfect for power amplifier medium - small (under 200 Watts), since at low freq not continue to strengthen (especially in the infrasound / below 20Hz). So that the movement of the speaker is more focused on the punch bass frequency 60Hz-120Hz, while the 20Hz down to do strengthening decrease again so the movement of the speaker does not move useless (move below 20Hz). It is suitable for speaker 4.5 inch - 8 inch, which is generally less good while working under 40Hz

Control :

P1 (50k) is used as Volume Control.

P2 (100k) used as Balance.

P3 (100k) is used as Bass.

P4 (100k) is used as Treble.

U1A used as a buffer for Baxandall Tone Control as well as a signal amplifier by + 6dB (R2 <220K> / R1 <100k>)

Why U1A inverted? because at the Baxandall Tone Control (U1B) phase inverted 180 °, so to make the output signal back to 0 °, then

required phase inverting again (inverting) of 180 ° so that the output signal becomes 360 ° or 0 °.

If it is not necessary strengthening of + 6dB at the inverted buffer, replace R2 into 100k (R2 = R1) so the gain is pretty into 1x or 0dB.

C2 together with input impedance formed Baxandall Tone Control High Pass Filter that serves to limit the strengthening of the infrasound freq. Also functions to block the DC offset of U1A.

If you want the summit to strengthen Bass is at lower freq then raise the value C3 for example be 33nF (eg using large speakers above 12 inch). If you want bass reinforcement peak at slightly higher freq then change the value C3 for example be 12nF. If using 18nF then strengthening Bass peak is at ~ 50Hz.

C4 is used for setting the strengthening of treble, treble reinforcement if deemed freq less fit, please replaced the value of C4. If the sound is less rugged treble can be tried by raising the value of C4, if less refined treble sound try lowering the value of C4.

R3 and R4 determine the amount of boost or cut the Bass. R6 and R7 determine the amount of boost or cut the treble.

Cf is used to limit the strengthening treble at ultrasonic frequency (above 20kHz), if deemed necessary, please do not ignore this component (blank).

R8 serves to to block the capacitance and inductance of the cable-sheath (shielded) for signal output, thus preventing oscillation at U1B which may be caused due to the use of the cable sheath is long (more than 2 meters).