Too many grounds? (Proper gound wiring)

[DeusM]

Sup guys? So, I was watching some videos about ground loop and found this:
https://www.youtube.mco/watch?v=ep0jAeq1kzM

So you probably already know about this but I don't so I have a couple of questions. When wiring a circuit inside the enclosure is it betther that all "grounds" came out from the pedal by one cable? Including grounds from switches and jacks? What I mean is it better to have only one cable coming out of - from the DC input?

[reddesert]

Ground loops are a bigger worry in amps, especially tube amps, where you can have higher voltages and currents inducing small currents in looped ground wires, causing small voltage offsets, hum, etc.  The maker of that video is a fan of tube radios.

In a pedal powered off 9V that is inside a metal enclosure, star grounding is usually not the highest priority thing to be concerned about.

[EBK]

I purposefully have several dedicated ground wires coming from the DC jack in all my builds. 
Input jack and output jack each get one (my input jack is isolated from the enclosure).
Circuit gets one (sometimes more, depending on what it is or how it is arranged).
LED ground pad on stomp switch gets one.
Any pot or switch connections to ground get one.

Is what I do necessary? No.
Is it beneficial? It's debatable.
Does it make me happy? Yes.

[DeusM]

Great answers guys!  Now I'm not too worried about it.

[Plexi]

I always use the enclosure as ground base.
From dc jack, to any jack ground.
From there to 3pdt or another jack ground.
Sometimes, I use the 3pdt ring with a wire on it, to the switch.

Which is closer, better.

[EBK]

Once you start relying on the enclosure as a ground current conductor rather than just a shield, you run the risk of receiving a scolding or lecture explaining why you shouldn't do that. So, in at least one way, you could say it increases noise. 

[Plexi]

Once you start relying on the enclosure as a ground current conductor rather than just a shield, you run the risk of receiving a scolding or lecture explaining why you shouldn't do that. So, in at least one way, you could say it increases noise. 

So...sometimes its a mith?

[anotherjim]

I star them. Output jack ground is my star point, since that's the one nearest the main ground at the amp. Don't necessarily star them on the board - too small an area to matter in my opinion, though I'd give an LFO circuit it's own ground leg.

[edy_wheazel]

 From the circuit I have only one GND. As much as possible I try to star them (in jack, out jack, power jack, circuit) on one of the jack's (in or out). Sometimes the power jack GND goes to the board (if it's closer). Starring it's not a "must", but it's easyer, and I prefer connections as short as possible.
Be carreful about GND loops, this is why I have only one GND pad on the board.

[DeusM]

this is why I have only one GND pad on the board.

Thats interesting. I was thinking if the paads could make ground loops. Kow I know.

[Tony Forestiere]

Once you start relying on the enclosure as a ground current conductor rather than just a shield, you run the risk of receiving a scolding or lecture explaining why you shouldn't do that. So, in at least one way, you could say it increases noise. 

I see what you did. Clever and well played.

*edit*I prefer a ground pour when possible.

[darklife]

New here..

With all my builds I always ground to chassis at one point only. With effects units or small amps the chassis ground point is right at the input jack which usually is in direct contact from the nut and metal body. If more than one exposed metal jack is used on a metal body, only tie ground to one of them, let the body fulfill the other ground points if it's a large box. Think of electrical ground as only one big wire, if you double them up in parallel at different lengths and push current through them that's where the hum comes from. (this can apply to electrical outlets too when combined with instrument cords grounded from same units, hence the ground lift option on some amplifiers)

If I am worried about safety I will ground direct to chassis somewhere near too, or right at the three wire (hot, neutral, ground) power input, especially if it's a metal enclosure which I believe is required by electrical code in most places.
If it's driven by a single wall plug without a ground I make sure either the internal power supply in my design is doubly insulated electrical Class 2 (separate transformer cores separated in the PSU transformer). Wood boxes count too because your instrument will become live through the jacks ground if something fails.
With wallwart driven stuff I don't worry since technically those are suppose to be double insulated from the mains power.

Now when it comes to earth ground compared to power ground, and add in the confusion of ground loops between those two and other points, there is a simple method I keep in mind..
Only ground your circuit board at one point to the chassis, if current draw is an issue on the circuit itself make sure to star ground or ground rail the low level audio stuff that is most sensitive and only connect that to the point of the circuit boards power input, keep the high current stuff like power amplifier stages on its own star ground and run it to the same power input. So think of it like a tree, your tree starts with power supply ground, potentially tied to chassis ground at your jacks input or near the power cable coming in, then from their it branches out to two main branches, one to all of your preamp stuff, one fat one to your power amp stuff in the circuit.
This will prevent almost all ground loops.
With guitar pedals using low level audio this is almost never a problem. Ground loops really only show their evil with power amplifiers.

Safety is another concern and the most important. If you have a metal chassis with built in supply, use a three prong plug and ground the chassis to the ground pin directly after the cord enters the unit. From there you can ground it right to your input jack (like guitar input) and from there to your circuits. This is safest so that in case something catastrophically fails it will not harm the player. Use the appropriate fuse at the input too if it's a power amp.
Sadly most older electronics do not conform to these rules. I have a lot of old tube gear and pre-1970s stuff that uses a two prong cord going to a grounded metal body . Three prong cord replacements can be a potential life saver from this old tech laying around peoples benches.

With wallwarts make sure to know exactly what class of a power converter it is before designing around it. Switching power supplies that plug into the wall are the worst offenders and most dangerous.. China anyone? Not to mention the switching electrical noise.
Just hope you have a good ground to the wall plug somewhere when one of those $3 wallwarts fail. There's a reason I still like the transformer types that are double insulated from AC.
Hope that was a good first post 

[darklife]

I should explain one more thing, earth ground V.S. electrical ground.
Earth ground is often confused with electrical ground, but both serve a different purpose. Earthing is often done at the power box coming into your home via a copper rod buried and connected to your houses electrical ground.
Earth ground both protects against lightning and can help with radio frequency interference if you have local radio stations near by.
To confuse matters more some designers consider earth ground to be where the ground wire comes into their product from the power cord, and electrical ground everything inside of their unit. This is not the proper definitions in my opinion.
And to add a little spice to the convo.. with audio we like to star ground things for ground loops right? Well with RF (radio frequency) electronics the opposite is actually the case, having tons of ground points across the circuit to prevent resonate circuit board traces or leakage. Funny how vastly different audio is from radio stuff. It's like completely different worlds, and I love working in both
If you don't want RF in your audio gear, don't design it like RF equipment.

[EBK]

New here..

....

Hope that was a good first post 

Welcome to the forum! Yes, that seemed well-grounded for a first post. 

[EBK]

I love the look of RF circuitry, particularly this "messy construction" stuff.  Ground is anywhere!

No personal experiencing building this sort of thing though, but it sure looks like fun.

[George Moore]

 Series wiring might save a little bit of wire.
  Beyond that there may be somewhere it matters @9volts...specifics would be detailed for where/when this would ever matter, common suspects for trying to detect a difference would probably be very high gain or "wavy or spikey" circuits like an LFO or voltage doubler, where all of a sudden current draw rises or falls.