Hello! I need make wah wah pedal too. And i try make it with tl072 too. And it not working After i went in ethernet to find answer. I find this forum and tried fix my problem, but i have not meaning what you fix. If this not difficult for you, can you send circuit or say me what you change in main circuit? This will be very pleasant and helpful for me. Thank.

Mod: Created your own thread
Link to old thread:
https://forum.allaboutcircuits.com/threads/wah-pedal-question.187619/post-1742770

 

What is not working? The original Instructable circuit is too simple to produced WAH sounds.

Does your filter circuit produce an output sound of only a few frequencies?
The pedal is supposed to change the resistance of potentiometer R2 to change the filter frequency.

 

What is not working? The original Instructable circuit is too simple to produced WAH sounds.

Before i connect battery, sound is ordinary. After connecting battery, sound is disappear.

 

Please attach your schematic with power supply connections and load resistance.