That link doesn't display - it redirects me straight to the Photobox front page.
Very strange, if I click on it works for me. Try this
I think it works for you because you are still logged in into that page (so a cookie is set). It likely won't work for anyone else unless they create an account or something.
The Imgur picture loads ok:
Now, lets see whether I understand what you have done correctly:
- You have a guitar pickup connected to something called "over" (I guess some sort of an effect - sorry, I am not a musician!) using a shielded cable (most likely not a coax ...). That then goes into the Zoom effect box and the wah wah effect and out to the amp. OK.
- The Zoom box is powered & controlled by the Arduino using the USB shield. OK.
- The power wiring is, umm ... interesting. So you have decided to distribute only the +9V and the return path is over the shields of all that signal wiring, through the USB shield & the Arduino back to the power supply? And you are wondering why are you having weird noises in the signal?
Guess what happens when the Arduino or the Zoom produce a larger power spike (e.g. because something internally just turned on). More current flows into the ground wire - the ground "jumps" up for a moment (the current doesn't flow back to the power supply instantaneously because of parasitic inductances and capacitances of the wiring). Because your wah wah, your over and even the amp get signal ground level from this unstable ground, they see it as a spike in the signal (remember - voltage is a potential difference between two points, it doesn't matter if it is the "red" or the "black" wire changing!) and will happily amplify it - and you suddenly hear stuff like your "tap tap" noise.
I believe you are doing MIDI control of the Zoom G3 with the Arduino and MIDI happens to have an Active Sense message sent every 300ms to detect whether the device didn't get unplugged. Guess what is the period of those tap-tap noises in the MP3 file you have linked before. Yup, every ~300ms ...
If you have used the star grounding system, each device would have its own power and ground wire back to the supply. Then the above cannot happen because even if the Arduino makes a current spike, that spike will affect only its own ground wire. The rest will still keep their "clean" ground connected to the power supply. The supply has a very low impedance output, so any spikes that get to it will get "eaten" by the large output capacitors and won't propagate to the other devices.
You definitely do need to rewire this - not only because of the noise problems but also because it could literally fry something. The signal circuits aren't designed to carry the power currents of everything you have there. E.g. the USB shield is rated only for 500mA of current - and you are using it to return the current consumed by
everything in your setup to the power supply.
but I would use it for the same reason as the video adopting the power supply https://ibb.co/d984kG, although I imagine it will not work with digital noise. I would put the mumetal sheet under the wahwah, in what sense do you speak of a shortcircuit ?
I was thinking about you trying to put the metal foil inside of the power supply case. Sure, if you put it under the wah wah pedal, it will be unlikely to cause a short.
I powered Arduino separately in two ways:
The problem with your Arduino is not the power supply but your bad wiring setup. See above. Once you fix that, the problem will most likely go away.
Initially I did not think about the toroidal, otherwise I would have opted for that, but for now I do not want to spend any more money, and if I do not resolve in any way use this https://ibb.co/d984kG and keep it away from the pedals.
That toroidal trafo costs ~20 bucks. How much did you spend on that mumetal sheet? If you are building something that should last you for a while, you want something that is robust and reliable so that you won't have to do a rubber chicken voo-doo dance around it to get it to behave every time.
However, I would still rather replace the supply with something that is hermetically sealed and professionally made, whether that TrueTone adapter of yours or another one. That homebuilt supply of yours is a problem waiting to happen. The linear voltage regulators will get hot in the plastic box, no components are mechanically fixed to anything ("flapping in the breeze" - imagine what happens after tossing this in your travel case few times - the PCB tracks will break/peel off), there is no fuse, the vent holes will allow dirt & water ingress - I don't know what kind of music you play but I have seen both gear getting rained on and gear getting beer (or worse!) spilled on at events. Do you want to risk that with a mains device?
If some drunkard gets fried because they have spilled beer in your kit and someone finds this gizmo of yours there, you could be in a nasty legal mess even though it was his fault and your power supply was not the source of the injury. In many countries you have no right to do anything with mains unless you are a licensed electrician.