# Question on how to wire a common anode LED



## ADAOCE (Mar 31, 2021)

So I’ve built a true bypass switcher with one tuner loop and four loops. I bought four common anode bicolor leds for the four loops. I want to wire the led to the 3PDT so that the led is red when bypassed and green when engaged versus the one on or both on setup. I could hook one side up to the normal led spot on the footswitch (lug 2) with ground in the middle on lug 5 which would make it green when engaged. My question is instead of wiring the red right to ground so it’s always on, could I wire it to lug 8 (lug 8 is jumped to lug 1) so that it’s connected to ground when the loop is bypassed? My only concern is that when the loop is engaged, it’s not connected to ground but it’s still jumped to lug 1 which is the loop send. Would that cause any issues? Would the loop send be connected through the led to ground or the cathode?


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## knucklehead (Mar 31, 2021)

What a great gadget - to you have a schematic for this?


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## ADAOCE (Mar 31, 2021)

..:: How to make your own True Bypass Strip ::.. taken from www.singlecoil.com
					

singlecoil.com - the musicians DIY electronics source for free



					www.singlecoil.com
				




I basically followed the project on this page. There is a ton of info in here about other things you can do like master bypass, wet and dry split, tuner mutes etc. I opted for the tuner and four loops. It’s really simple it’s just wiring five true bypass 3PDT switches in a row. There are schematics on the page though to help you visualize it.


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## ADAOCE (Mar 31, 2021)

The enclosure is a Hammond 1411t and I had a friend at work powder coat it


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## knucklehead (Mar 31, 2021)

ADAOCE said:


> I basically followed the project on this page.



Thx!


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## Barry (Mar 31, 2021)

The 3pdt boards at guitarpcb, would likely be the easiest way, there already set up for common anode and have the CLR on them


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## ADAOCE (Mar 31, 2021)

Barry said:


> The 3pdt boards at guitarpcb, would likely be the easiest way, there already set up for common anode and have the CLR on them


Wish I saw that a couple weeks ago but thanks for pointing it out. 

I’m wiring up the switches in this scheme 

Is there no way to do this way? The real problem is the red green bicolor is not very good. The green is pretty dim compared to the red. Im trying to see if I have the green always on and switch the red side off when engaged just not sure where to put it


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## Mcknib (Mar 31, 2021)

Just wire ground for the bypass colour to lug 6 that's grounded in bypass mode by lug 5 the same as 4 is grounded by 5 in effects mode remember the middle row is common to the top and bottom row or throw so when it's switched or thrown to bypass 5 grounds 6

Lug 1 is jumpered to 6 which I think you're referring to as 8 so yes connect your red side cathode to there


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## ADAOCE (Mar 31, 2021)

Mcknib said:


> Just wire ground for the bypass colour to lug 6 that's grounded in bypass mode by lug 5 the same as 4 is grounded by 5 in effects mode remember the middle row is common to the top and bottom row or throw so when it's switched or thrown to bypass 5 grounds 6
> 
> Lug 1 is jumpered to 6 which I think you're referring to as 8 so yes connect your red side cathode to there


 Is this numbering correct? It sounds like you’re describing the transpose of what I think the numbering is.


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## Mcknib (Mar 31, 2021)

I should look at images! we're talking about the same lug your 8 is my 6

The columns are the poles as you know a 3PDT is basically three SPDTs side by side so I've always  counted the pole lugs the standard way top to bottom 

But we're talking about the same lug


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## ADAOCE (Mar 31, 2021)

Mcknib said:


> I should look at images! we're talking about the same lug your 8 is my 6
> 
> The columns are the poles as you know a 3PDT is basically three SPDTs side by side so I've always  counted the pole lugs the standard way top to bottom
> 
> But we're talking about the same lug


Right that totally makes sense idk why I was thinking it would be numbered across. To be fair I added the numbers to the second image!

sweet I’ll get this thing wired up. Kind of tedious all this wiring though I would easily pay for a loop master box they seem to be priced well


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## Mcknib (Mar 31, 2021)

To be honest I never even looked at the image, story of my life jump right in

Me building a wardrobe:

Instructions? What instructions, oh I musta binned them! Hold on and I'll put this door the right way up

Meant to say you will find the green side dimmer you can get round it by having separate CLRs on the cathodes instead of the anode higher value red side and minimum green side would even them up a wee bit


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## ADAOCE (Mar 31, 2021)

Mcknib said:


> To be honest I never even looked at the image, story of my life jump right in
> 
> Me building a wardrobe:
> 
> Instructions? What instructions, oh I musta binned them! Hold on and I'll put this door the right way up


Hah I hear you on that. I get that sense of confidence and then realize I put some part backwards...


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## ADAOCE (Apr 1, 2021)

@Mcknib so I  finished wiring this thing up and all the wiring checks out I get bypass when I should and shouldn’t but the four loops that have the red side on lug 6 make a huge pop sound when you engage the loop. It also distorts a little bit when you play. Bypass functionality is perfect. I’m thinking the led being connected to the loop is causing this reaction which is what I was afraid of. Maybe I can put a resistor or something somewhere?

the red green on off function looks cool but at the end of the day I need function over form


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## Mcknib (Apr 2, 2021)

There's some info regarding LED pop here






						True Bypass Pedal Popping with LED
					

True Bypass Pedal Popping with LED



					www.diystompboxes.com
				









						AMZ - LED Popping
					

How to stop the pops in audio from LED current surges when switched.




					www.muzique.com
				




With the red side being brighter it could be the sudden switch in current requirements that's causing it


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## Many__Of__Horror (Apr 2, 2021)

ADAOCE said:


> @Mcknib so I  finished wiring this thing up and all the wiring checks out I get bypass when I should and shouldn’t but the four loops that have the red side on lug 6 make a huge pop sound when you engage the loop. It also distorts a little bit when you play. Bypass functionality is perfect. I’m thinking the led being connected to the loop is causing this reaction which is what I was afraid of. Maybe I can put a resistor or something somewhere?
> 
> the red green on off function looks cool but at the end of the day I need function over form


I've had about 50/50 luck with popping when using these LEDs in builds. Never had a pop from a standard LED


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## Mcknib (Apr 2, 2021)

Many__Of__Horror said:


> I've had about 50/50 luck with popping when using these LEDs in builds. Never had a pop from a standard LED


Yeah I'm not a massive fan of them don't see the point unless you're gigging in dark venues then it's a visual showing you've not forgotten to power it


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## ADAOCE (Apr 2, 2021)

Mcknib said:


> There's some info regarding LED pop here
> 
> 
> 
> ...


Tha is for the info yeah I’m thinking that’s the likely culprit because the first loop is just a standard led and no pop. Might just clip the red side so it’s green only


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## ADAOCE (Apr 2, 2021)

Many__Of__Horror said:


> I've had about 50/50 luck with popping when using these LEDs in builds. Never had a pop from a standard LED


Glad I’m not alone in this! It’s too bad because it looks neat but oh well I’ll eventually replace the switches for relay bypass and soft clicks at some point


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## knucklehead (Apr 2, 2021)

I am likely to build something similar - a summing buss for 4 pedals with a master bypass - and intend to use Tayda's red/green self-indicating switches. Your post inspired this.

THAT said . . . .

Is your DC power source isolated from the enclosure or do they share your box's ground?


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## ADAOCE (Apr 2, 2021)

knucklehead said:


> I am likely to build something similar - a summing buss for 4 pedals with a master bypass - and intend to use Tayda's red/green self-indicating switches. Your post inspired this.
> 
> THAT said . . . .
> 
> Is your DC power source isolated from the enclosure or do they share your box's ground?


So it’s not separated the ground from the DC jack is what is used to ground all the jacks and the enclosure. I thought about grounding the input jack only and using all insulated jacks but I ended up doing it the exact way that that webpage I pasted did.

I did come across a scheme for wiring the 3PDT so that the led leads don’t touch the signal wires. I’ll find it and post it


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## ADAOCE (Apr 2, 2021)

Like I said earlier it’s definitely something to do with the bicolor leds because the one loop with a normal led passes signal through the loop quietly and flawlessly.


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## knucklehead (Apr 2, 2021)

ADAOCE said:


> I did come across a scheme for wiring the 3PDT so that the led leads don’t touch the signal wires. I’ll find it and post it



I am using a DC jack that is plastic and isolated - so far so good. I hope you can find that schematic that cane to mind - and thx for hunting it down!


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## ADAOCE (Apr 2, 2021)

This is it. It’s for a common cathode led tho so the difference will be that the anode leads wil go on the ends and instead of 9v in the middle you will bring the power ground there. This is a more efficient use of the lugs to still ground the circuit input during bypass. Wish I noticed this before wiring all mine up


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