Wah testing question...

[Govmnt_Lacky]

So I have my DIY Wah set up and connected to my test bench. I have a 440Hz signal at 100mV pumped into the circuit. My question is what exactly I should be looking for with the effect on. I see the signal goes down to about 50mV and as I rock the pedal from heel to toe it looks like the amplitude gets larger towards the center of the rotation. As I continue towards full-toe-down, the signal then decreases back to around 50-75mV.

Is this correct? Also, how can I tune this with my scope to get the best usage of the pot from heel to toe?

[Govmnt_Lacky]

Does anyone know where I can find what a Wah looks like on an oscope? Screen shots, word descriptions, anything that will help me to tune mine.

[Ronsonic]

440Hz is a bit high for what we do. Try 200, more in the fat range of guitar.

For a wah or phase shifters, choruses, flangers any effect that has more affect on tone than level use a square wave 100Hz is good. You'll see the edges roll and the top slope depending on the wah position or the action of the effect you're testing.

This won't really help you tune it, but will show that it is working.

[tubelectron]

Hi Govmnt_Lacky & Ronsonic,

Very interesting topic, as I am working on wah projects, and DIYed some... But it is sometimes "foggy", so making appropriate measurements and share it would be an interesting idea.

Is the 440Hz a tuning frequency of the variable LC circuit of your wah, when, say, the pedal is down (treble sound) ? Can you describe your measurement protocol and settings, so I can reproduce the same on my different wahs (DIY and originals) to have a comparison ? (I have the required oscilloscopes, DMMs, audio and RF generators).

Thanks & A+!