Wah Inductors. No hype. Just measurements.

[Stickman393]

Yeahhhh. Fuckin, I can't make heads or tails of it.

The difference is *extremely* minute. Tested driving both a 1meg load and a 5k load. The load makes a big difference, but this partial AC bypass barely registers on the graph.

Huh. I'm flummoxed.

 

[Stickman393]

Doing a little bit of an experimental build here. Mostly stock, except for the added adjustable gain on Q1 and the range cap.

Its not as clean as I want it to be, just a prototype.

The range switch on the wah is gonna start from a 8.2nF baseline and. Five positions for parallel caps: empty, 1.8nF, 4.7nf, 6.8nf, and a 13nf.

Definitely need to design a switch-mounted daughterboard for this setup, though.

Also added a10pf cap across the collector and base of each transistor. Miller capacitors. Good for noise rejection and trimming the highs a touch.

Just slapped it together. We'll see how she behaves tomorrow.

 

[Chuck D. Bones]

Increasing Q1's gain does two things.
1. It increases the signal level at Q1-C (the output) and Q2-E (the feedback path).
2. It extends the low end of the Wah range.

 

[anevilspar7an]

Doing a little bit of an experimental build here. Mostly stock, except for the added adjustable gain on Q1 and the range cap.

Its not as clean as I want it to be, just a prototype.

The range switch on the wah is gonna start from a 8.2nF baseline and. Five positions for parallel caps: empty, 1.8nF, 4.7nf, 6.8nf, and a 13nf.

Definitely need to design a switch-mounted daughterboard for this setup, though.

Also added a10pf cap across the collector and base of each transistor. Miller capacitors. Good for noise rejection and trimming the highs a touch.

Just slapped it together. We'll see how she behaves tomorrow.



View attachment 123556

What's that little board between the main pcb and the rocker?

 

[Stickman393]

My little mosfet reverse/over voltage protection and power filtration board.

Got a dip switch in there to remove the series resistor should someone have a good quality PSU to power the thing with. So, ya know, your 100 ohm resistor isn't artificially lowering the voltage the circuit sees. By an infinitesimally small amount.

Yeah. Its way overkill.

 

[Stickman393]

Another!

I'm redesigning the turret board to make it slightly smaller and to move the inductor away from the right hand side. Tends to crowd the 9v Inlet a touch.

So, this is my last of my V1 boards that I made. This guy gets a 47k input resistor, adjustable Q1 gain, an input cap I pulled from an old organ board, 2N3565s, a mix of metal film and carbon composition caps, Miller caps, and the range cap is NOS Russian PTFE.

Why? Because I felt like it.

 

[Chuck D. Bones]

Where does is that 680nF cap go in the circuit?

How much louder is it when you engage the pedal compared to bypass?

 

[Stickman393]

Almost forgot:

This is a tweak I picked up from the EVH wah. It replaces the 220nf cap that connects to the "output" pin on the potentiometer.

Aint gonna make a load of difference. But it's there.

 

[anevilspar7an]

It's something to try on downtuned bass, I did notice something happening when I did it to my EB wah and a ShamWah board, but it's subtle.