Author Topic: Where do the ground wires go?  (Read 1204 times)

Cmwm

Where do the ground wires go?
« on: March 07, 2018, 05:58:04 PM »
Hey guys,

Iíve just started my first build since a butchered attempt a few years ago.

Iím doing the woolly mammoth clone

My question is where do the ground wires go? What is the principle behind the ground wires (do they all go to the outputs in whatever order? Do they all go to the board?)

Iíve tried wiring this up, improvised out of impatience and found myself completely lost.

Iíd like to understand how to get this to work so I know for future builds, but if anyone has an example of it correctly wired off board that would be greatly appreciated too.
« Last Edit: March 07, 2018, 05:59:56 PM by Cmwm »

EBK

Re: Where do the ground wires go?
« Reply #1 on: March 07, 2018, 06:27:09 PM »
Welcome to the forum!

The concept of "ground" is very important, and can be complex if we were to cover it all in one sitting.  So, for now, here is the brief version:

Everything labeled "ground" gets connected to the negative terminal of your power source. 

Keep asking questions until you understand all that you want to understand.
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Re: Where do the ground wires go?
« Reply #2 on: March 07, 2018, 06:28:43 PM »
In small audio, "ground" mostly means "common". Half of all wires end up connected together, "common". This *includes* input and output jack shells, often one Power connection. We work high-gain audio inside metal boxes, and the box is tied to common.

Utility power wall-outlet work has other implications. But in Pedal-World, if your main amplifier is correctly grounded (3-pin plug, working) then the pedals get that ground through the audio cords.

Cmwm

Re: Where do the ground wires go?
« Reply #3 on: March 07, 2018, 06:34:12 PM »
Hey, thanks. Iím glad to be getting involved!

Does everything need to be connected ďdirectlyĒ to the negative terminal, or is it all connected to a sort of loop that works its way back to the negative terminal? And Iím assuming the negative terminal goes out through the cable and out to the Mains?


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GibsonGM

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Re: Where do the ground wires go?
« Reply #4 on: March 07, 2018, 06:45:28 PM »
Welcome Cmwm,

In the end, they all go to the negative terminal (UNLESS it's a positive ground circuit ... far less common, but they are out there for sure, some fuzzes and so on).     The route they take there is debatable, sometimes.     

It's mostly agreed that all the grounds on the circuit board should go to 1 spot on it, which then can go off to the input jack's switch lug...then, the other switch lug goes to battery ground.    This is how the input plug 'turns on' the pedal, and why you need to pull it out when you're done or the battery eventually goes dead.     The method of running all board grounds to one place is called 'star grounding'; I'm sure there are whole articles on it, on the internet.

So, it's a 'method', but not a LOOP...since a real ground loop is BAD! (lol)  Keeping it direct and as short as you can would be the idea...avoids noise, picking up RF and general crappy performance.

Take a look at some of these wiring diagrams (and keep this file for your use!), they will make the idea clear, I'm sure.  http://www.generalguitargadgets.com/how-to-build-it/technical-help/switching-and-wiring/bypass-sw-options/
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Cmwm

Re: Where do the ground wires go?
« Reply #5 on: March 08, 2018, 02:36:52 AM »
Is a stereo jack necessary for a circuit to work? Iíve used a mono jack for the input though Iím sure thatís not the only issue with my wiring hahaha


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antonis

Re: Where do the ground wires go?
« Reply #6 on: March 08, 2018, 06:57:17 AM »
Is a stereo jack necessary for a circuit to work?
Strictly speaking, No..!!

Ring (middle) lug of stereo jack acts as a ground connection "switch" (establishes continuity via plug body) so pedal isn't powered when unplugged..
(electrons from negative pole of battery or power supply can't find path to proceed to positive pole..)
« Last Edit: March 08, 2018, 08:13:57 AM by antonis »
Can't follow your signature changes, Stephen..!!

GibsonGM

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Re: Where do the ground wires go?
« Reply #7 on: March 08, 2018, 07:57:07 AM »
You can wire it any way that makes sense, and the jack is just to turn it on or off, as stated.   

The stomp switch and LED are also only for 'when in use'....when I build a circuit, to test that it works I always connect a mono jack to input and output, with the sleeves connected to ground with jumper wires.   Sometimes the jack grounds are just connected to each other, with one to ground.   This often means that all my ground wires meet at the ground wire coming from the PCB.   This is fine to test a circuit.   It may be a little noisy, depending what the circuit is.    By testing the PCB this way, I know that any future mistake will be caused by the switch or jack wiring, 99.99% of the time (not 100% because the board COULD be damaged while handling, but that's not likely).

When laying out the PCB, one wants to make each stage's ground go to a board ground point (to avoid ground loops..this is 'star grounding').   Then, when it's time to install the jacks and switch, LED etc., and put it in the enclosure, one of the common wiring schemes I linked to can be used.    But to test the circuit, as long as the grounds are connected, you are good to go!  Complete the path, physics will do the rest  :) 
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antonis

Re: Where do the ground wires go?
« Reply #8 on: March 08, 2018, 08:43:27 AM »
when I build a circuit, to test that it works I always connect a mono jack to input and output, with the sleeves connected to ground with jumper wires.
Can't recall the times troubleshooting a "dead" pedal with unplugged stereo input jack ...  :icon_redface:
Can't follow your signature changes, Stephen..!!

GibsonGM

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Re: Where do the ground wires go?
« Reply #9 on: March 08, 2018, 10:22:09 AM »
when I build a circuit, to test that it works I always connect a mono jack to input and output, with the sleeves connected to ground with jumper wires.
Can't recall the times troubleshooting a "dead" pedal with unplugged stereo input jack ...  :icon_redface:

It happens to everyone!   Or not connected to the amp  ;)
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Tony Forestiere

Re: Where do the ground wires go?
« Reply #10 on: March 08, 2018, 09:44:23 PM »
It happens to everyone!   Or not connected to the amp  ;)

Yessir. PCB wired up and guitar and amp In/Out  reversed. "Why isn't this working?"
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antonis

Re: Where do the ground wires go?
« Reply #11 on: March 09, 2018, 07:56:20 AM »
Or not connected to the amp  ;)
Perhaps that's the ultimate lever of troubleshooting..
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Can't follow your signature changes, Stephen..!!

Cmwm

Re: Where do the ground wires go?
« Reply #12 on: March 13, 2018, 04:40:56 PM »
Back once again!

Tried to guess my way to a wiring. Hereís a rough drawing of how Iíve currently got the off board wiring. Itís not working.



If there are no glaring issues with what Iíve done then Iíll move on to reflowing the board as that seems to be the #1 suggestion.

Any ideas and suggestions welcome, trying to learn so Iím open to scrutiny.


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bluebunny

Re: Where do the ground wires go?
« Reply #13 on: March 15, 2018, 04:06:03 AM »
Wiring looks OK (assuming you chose the right lugs on the jacks).  Time for photos of your board.
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antonis

Re: Where do the ground wires go?
« Reply #14 on: March 15, 2018, 08:17:31 AM »
And the right plugs on the jacks..
Can't follow your signature changes, Stephen..!!

Cmwm

Re: Where do the ground wires go?
« Reply #15 on: March 15, 2018, 09:46:55 AM »
Cool Iíll get some photos posted once I get home. Thanks for your help guys


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Cmwm

Re: Where do the ground wires go?
« Reply #16 on: March 15, 2018, 04:14:41 PM »
Here we go guys,




All the Cooper traces have no connections over, checked and double checked.

Had difficulties reading the colours of each resistor so used a multimeter and had each component organised and each component was called for, its possible one reading was close to another reading and they ďoverlappedĒ and ended up swapped.

I can add photos off the pots but itís difficult to get a photo of it all making sense


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vigilante397

Re: Where do the ground wires go?
« Reply #17 on: March 15, 2018, 04:55:07 PM »
It's hard to tell since the second image is pretty blurry, but are you ABSOLUTELY SURE there are no solder bridges between tracks? Because (again could be the blurriness) but I swear I see some in there.
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Cmwm

Re: Where do the ground wires go?
« Reply #18 on: March 15, 2018, 05:25:53 PM »
I think thatís flux reflecting light, to be sure Iíve used a scalpel to score between them and get rid of anything.

Noticed some shoddy solder on the output jack, waiting for the soldering iron to warm up so stay tuned!


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Cmwm

Re: Where do the ground wires go?
« Reply #19 on: March 15, 2018, 05:40:04 PM »
Still silent.

Any good resources for troubleshooting with a multimeter (if thatís the logical next step)


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