Hi everyone,
I started with a new project yesterday for voice changing using dual op-amps.. Its a band pass filter but when I tried building it, it returns a houling sound all the time.. The pre-amp(1st section) and power amp( 3rd stage) works fine when coupled directly without the band pass stage in between.. but when i connect the 2nd stage without even giving an input, it starts to houl.. something is making it oscillate so badly.. I replaced the op-amp chip and changed power supplies and batteries but no gain.. Somebody please help me with this.. i suggested this circuit for my friend's mini project at college and now it doesnt give output, so I tried it myself and no gain..
This is the link for the site
http://www.redcircuits.com/Page112.htm
This is the circuit
P1______________10K Log. Potentiometer
R1,R10__________10K 1/4W Resistors
R2_______________1K 1/4W Resistor
R3______________50K 1/2W Trimmer Cermet or Carbon
R4,R6,R7,R14___100K 1/4W Resistors
R5______________47K 1/4W Resistor
R8______________68K 1/4W Resistor
R9_______________2K2 1/2W Trimmer Cermet or Carbon
R11_____________33K 1/4W Resistor
R12_____________18K 1/4W Resistor
R13_____________15K 1/4W Resistor
C1,C2,C3,C8,C9_100nF 63V Polyester Capacitors
C4______________10µF 25V Electrolytic Capacitor
C5_____________220nF 63V Polyester Capacitor (Optional, see Notes)
C6_______________4n7 63V Polyester Capacitor
C7______________10nF 63V Polyester Capacitor
C10____________220µF 25V Electrolytic Capacitor
IC1___________LM358 Low Power Dual Op-amp
IC2_________TDA7052 Audio power amplifier IC
MIC1__________Miniature electret microphone
SPKR______________8 Ohm Small Loudspeaker
SW1____________DPDT Toggle or Slide Switch
SW2,SW3________SPST Toggle or Slide Switches
J1____________6.3mm or 3mm Mono Jack socket
B1_______________9V PP3 Battery (See Notes)
Clip for PP3 Battery
I started with a new project yesterday for voice changing using dual op-amps.. Its a band pass filter but when I tried building it, it returns a houling sound all the time.. The pre-amp(1st section) and power amp( 3rd stage) works fine when coupled directly without the band pass stage in between.. but when i connect the 2nd stage without even giving an input, it starts to houl.. something is making it oscillate so badly.. I replaced the op-amp chip and changed power supplies and batteries but no gain.. Somebody please help me with this.. i suggested this circuit for my friend's mini project at college and now it doesnt give output, so I tried it myself and no gain..
This is the link for the site
http://www.redcircuits.com/Page112.htm
This is the circuit
P1______________10K Log. Potentiometer
R1,R10__________10K 1/4W Resistors
R2_______________1K 1/4W Resistor
R3______________50K 1/2W Trimmer Cermet or Carbon
R4,R6,R7,R14___100K 1/4W Resistors
R5______________47K 1/4W Resistor
R8______________68K 1/4W Resistor
R9_______________2K2 1/2W Trimmer Cermet or Carbon
R11_____________33K 1/4W Resistor
R12_____________18K 1/4W Resistor
R13_____________15K 1/4W Resistor
C1,C2,C3,C8,C9_100nF 63V Polyester Capacitors
C4______________10µF 25V Electrolytic Capacitor
C5_____________220nF 63V Polyester Capacitor (Optional, see Notes)
C6_______________4n7 63V Polyester Capacitor
C7______________10nF 63V Polyester Capacitor
C10____________220µF 25V Electrolytic Capacitor
IC1___________LM358 Low Power Dual Op-amp
IC2_________TDA7052 Audio power amplifier IC
MIC1__________Miniature electret microphone
SPKR______________8 Ohm Small Loudspeaker
SW1____________DPDT Toggle or Slide Switch
SW2,SW3________SPST Toggle or Slide Switches
J1____________6.3mm or 3mm Mono Jack socket
B1_______________9V PP3 Battery (See Notes)
Clip for PP3 Battery