DOD FX-17

[Sauerkret]

Hello all,

I am interrested in building a DOD FX-17 wah pedal.
Is it possible to controle the voltage change (0 to +5 volt) of the controller with a regular wah pot.
This would be useful to me as i intend to build it as a rackmounted effect.

thx, for the help

FYI.....i am a noob when it concerns electronics .

[David]

The FX-17, while an interesting beast, is probably not something that is DIY.  IIRC, the pedal operates a mechanism that varies capacitance, not resistance.  Creating a mechanism to vary resistance is MUCH easier and far more reliable.

In any case, Paul Marossy at www.diyguitarist.com has written a very scholarly analysis of the FX-17 which will tell you everything you wanted (or didn't want) to know.

[Paul Marossy]

Let's put it this way: I wouldn't even want to build this, and I'm not exactly a beginner.

It would be a challenging DIY project for several reasons.

[Sauerkret]

someone is going to help me with the build.
I'll have to make the PCB design/layout and he will make the board for me.
the only unknown to me is how to add a true bypass to the effect and to controll it remotely. the selection switch for wah/volume will be mounted to the rack unit.

[tackleberry]

Controlling it remotely could be a serious problem with that variable capacitor set up.

[noelgrassy]

If this is the FX that you must have why not score one off the interweb, take it's guts and mount them remotely and wire the
original controller with 30' leads that run back to your rack? Why does it have to be TBP? Don't you need an FX loop switch group
anyway? Make the loop switches all TBP and yer GTG.

+100 on Paul Marossy's dissertation on this muthah.

Have the fun!

Noel Grassy.

[mictester]

Let's put it this way: I wouldn't even want to build this, and I'm not exactly a beginner.

It would be a challenging DIY project for several reasons.

The electronics are simple - the mechanics are a bit harder.  Incidentally, no Paul, there are not enough stages for a good phase effect, but the mechanical design isn't beyond a competent DIYer.

DOD used that strange etched shape on the PCB to make the movement vs capacitance fairly linear, so that the 0 to 5 Volts is a (nearly) straight line.  My version of this pedal used a moving curved "paddle" attached to the pedal mechanism, and a fixed vane made of 4 X 3 cm of PCB material.  I experimented with LEDs, photocells and shaped shadows.  I tried crossed polarised lenses interrupting a light beam, and I've tried all sorts of potentiometers and variable tuning capacitors.  The DOD approach using the "homebrew" variable capacitor is by far the best!

The CMOS 4007 is getting quite hard to find, and is very susceptible to static damage.  I replaced one with a transistor oscillator, and got just the same results!

[R.G.]

I bought one for $35. Neat mechanical package. It takes in 0-5V. I don't think I could buy the parts for $35, much less make the housing.

[slideman82]

Hey! Few days ago a friend left him just to change its switch... interesting circuit, but I never suspect it worked with variable capacitance!

[Paul Marossy]

I bought one for $35. Neat mechanical package. It takes in 0-5V. I don't think I could buy the parts for $35, much less make the housing.

I have three of them now. I think they're really cool volume pedals. I don't really like how the input & output jacks are arranged, but I do very much like how the pedal functions. It's a very quiet volume pedal. Especially important when you use really high gain distortion pedals after it. I also like that it doesn't have a pot that can't do bad.