Gradual Subwoofer Bass Filter Circuit

Circuit MC33074 (Operational Amplifiers) and PT2351 (Subwoofer Crossover Low Pass Filter) based on 55Hz and 65Hz 75Hz 85Hz 95hz 6 Step Switchgear 105Hz stage material can be selected by changing the values ​​you can use different frequency

Bass Subwoofer Filter Circuit Frequency Table

Part list

6 R1,R2,R9,R10,R17,R18 10.7k
2 R3,R4 23.2k
8 R5,R6,R7,R8,R13,R14,R15,R16 97.6k
2 R11,R12 3.32k
RV1,RV2 20k trimpot
All resistor %1 tolerance metal film

C1,C39,C40 10uF 35V
C2,C4 100nF 63V
C3,C5,C14 100uF 16V
C6,C7,C8,C9,C12,C13 2.2uF 50V
C10,C11 470nF 63V
C41,C42 220uF 10V
CA1,CB1,CA3,CA5,CA6 47nF 63V
CD1 220nF 63V
CC1,CD5 22nF 63V
CA2,CA4 68nF 63V
CB2 15nF 63V
CC2,CD2,CC5,CC6 100nF 63V
CB3,CD3 33nF 63V
CC3,CC4 150nF 63V
CB4 6.8nF 63V
CB5,CD5 10nF 63V
CB6 4.7nF 63V
All fixed capacitors Polyester

ICs
U1 78L08 +8V regulator
U2 MC 33074 Quad operational amplifier
U3 PT 2351 Special subwoofer filter IC

MC33074: Single Supply 3 V to 44 V, Quad Operational Amplifier

Wide Bandwidth: 4.5 MHz
High Slew Rate: 13 V/ms
Fast Settling Time: 1.1 ms to 0.1%
Wide Single Supply Operation: 3.0 V to 44 V
Wide Input Common Mode Voltage Range: Includes Ground (VEE)
Low Input Offset Voltage: 3.0 mV Maximum (A Suffix)
Large Output Voltage Swing: -14.7 V to +14 V (with +/-15 V Supplies)
Large Capacitance Drive Capability: 0 pF to 10,000 pF
Low Total Harmonic Distortion: 0.02%
Excellent Phase Margin: 60°
Excellent Gain Margin: 12 dB
Output Short Circuit Protection
Pb-Free Packages are Available

PT2351: Subwoofer Cross-Over Low Pass Filter IC

CMOS Technology
Single Power Supply: 3V to 9V
Second Order Low Pass Filter Desig with Slope Rate = -12dB/oct
Third Order Low Pass Filter Desig with Slope Rate = -18 dB/oct
Low Output Impedance (Typ. 40 Ohms)
Least External Components
The Roll-Off Point ca be adjusted using a External Capacitor
2-Channel Inputs are mixed to a Single Subwoofer Output
Available i 8-pin, SO or DIP Package