# LEd color impact?



## Dali (Oct 27, 2019)

When LED color isn't mentioned in the building docs, does it means we can use any color sound/electrical wise (mainly the on/off state)?


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## Nostradoomus (Oct 27, 2019)

For the bypass LED? Use whatever colour you want, it has no effect on the sound.

Different colour LEDs have different forward voltages if you use them for clipping diodes, but in the switching circuit there’s no difference.


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## Chuck D. Bones (Oct 28, 2019)

If you use a color other than red for the ON/OFF indicator, you probably want to change the LED series resistor to get the right brightness.  Best to try it out with the LED, a 9V source and a resistor before you solder the resistor to the board.  I would not go lower than 1K.  These are the values I use, YMMV:
red 3.9K
green 2.4K
blue 1.5K
violet 1.5K


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## Jovi Bon Kenobi (Oct 28, 2019)

If you use different colored ultra bright clear LEDs from Tayda, kinda like the ones used in EQD pedals that burn holes in your brain, you may prefer to make the current limiting resistor (CLR) kinda high. I've gone as high as 47k on some of those types to tame the brightness.

My favorite indicator LEDs are the 5mm UV ones from Tayda. They are a nice purply blue. Coincidentally, they work really well with the suggested 4.7k CLR in most PedalPCB projects.


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## Chuck D. Bones (Oct 28, 2019)

I bought a bag of 100 UV LEDs from some random source in China for $2.50 incl shipping.  They're plenty bright and I try not to stare at them.


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## Nostradoomus (Oct 28, 2019)

I got a bag and of cool colour changing (RGBY) ones from a similarly unknown source, they’re pretty sweet!


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## Dali (Oct 28, 2019)

Do people here prefer 5mm or 3mm for ON/OFF indicator? 

I've check some build in the Build Reports Forum and it looks it depends of the builder or the pedal itself...


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## DGWVI (Oct 28, 2019)

Dali said:


> Do people here prefer 5mm or 3mm for ON/OFF indicator?
> 
> I've check some build in the Build Reports Forum and it looks it depends of the builder or the pedal itself...



I prefer 3mm, no bezel. But, I've used 5mm and bezels when I've felt saucy


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## Nostradoomus (Oct 28, 2019)

I usually do 5mm with bezel...mostly because I have more of them.


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## Chuck D. Bones (Oct 28, 2019)

&^%$*#@ RICKY!

I use 3mm in a 1/8" hole, no bezel.  If the board supports it, that's all it needs (see my Brown Betty build). If it's outside the board, then a drop of crazy glue gel on the inside keeps it in place (see my Scythe mod).


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## Jovi Bon Kenobi (Oct 28, 2019)

Up to you! I love the type 1 bezels that PedalPCB sells. And 5mm. They squeeze in perfectly and stay put. The LED just drops right in and clicks secure. If the bezels came even bigger I'd do it!


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## Cucurbitam0schata (Oct 29, 2019)

For what it's worth - I ordered the wrong resistors for my current build, and it was suggested that I could use higher-rated spare resistors. I ended up testing out blue LEDs with a 12k resistor. Looked good to me, fine brightness. 

LEDs - https://www.taydaelectronics.com/led-3mm-blue-water-clear-ultra-bright.html
12k's - https://www.taydaelectronics.com/r-12k-ohm-1-8w-1-metal-film-resistor.html


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## Cybercow (Oct 29, 2019)

For clipping diodes, different color LEDs do have different Fvds. But mind you, you need to get the clear colored LEDs. The cheap LEDs that are enshrouded in red, blue, green, yellow, etc plastic are all the same Fvd because they use the same white LED and just use colored plastic around the element to get the different colors. At least, that's what I've found in my experience. For On-Off indicators, the Fvd is of little concern.


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## Cybercow (Oct 29, 2019)

Nostradoomus said:


> I got a bag and of cool colour changing (RGBY) ones from a similarly unknown source, they’re pretty sweet!


How do you handle the noise the micro-CPU injects into the audio? I built a Luna Fuzz with transparent-shafted pots and used those color-cycling LEDs beneath the pots to illuminate th transparent shafts with transparent knobs. I could hear the micro-CPU noise as the colors cycled thru their changes. To correct that, I used a 0.1nF cap across each of the power supply lines on the PCBs on which the transparent-shafted pots and color cycling LEDs were mounted. Have experienced this micro-CPU noise?


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## Nostradoomus (Oct 29, 2019)

I’m not sure the ones I have are micro chipped, they look exactly like any other 5mm LED I have.


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## zgrav (Oct 29, 2019)

Sounds like a cool effect using the transparent pot shafts.   Was it easy to see in a lighted room?  Better in a dark environment?


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## Cybercow (Nov 1, 2019)

Nostradoomus said:


> I’m not sure the ones I have are micro chipped, they look exactly like any other 5mm LED I have.


Without a µCPU, I wonder how they actuate the color cycling? Do they auto-cycle with just two legs, or do yours have 4 legs? I have both and the ones with 4 legs do not auto-cycle. If they have two legs and auto-cycle the colors, there is very likely some sort of µCPU in them.


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## Nostradoomus (Nov 1, 2019)

There’s 2 legs. They were a random cheap eBay buy.


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## Cybercow (Nov 25, 2019)

Nostradoomus said:


> There’s 2 legs. They were a random cheap eBay buy.



With just two legs, they are definitely µ-chipped.


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## Nostradoomus (Nov 26, 2019)

That is one tiny ass chip then! Haha


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## Cybercow (Nov 26, 2019)

Nostradoomus said:


> That is one tiny ass chip then! Haha



Yes. they are very tiny. I was surprised too. But considering they come in bot fast and slow cycling versions, I can't see how they'd do it otherwise.

And the point remains that the tiny µ-processor does inject noise if additional filtering is not added near those color-cycling LEDs. More importantly, I'm looking forward to seeing how you apply one or more in a build.

Here's what I did with mine . . . . . Dark Of the Moon Demo


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## Cucurbitam0schata (Jan 24, 2020)

Coming back to this question:

I've built three pedals so far (Bit Captain / Phase II / Sea Horse - build reports are a comin'!). The LEDs for the Phase II (3mm green) and Bit Captain (3mm blue) called for 4.7K, had to up them to 10K+ to tone the brightness down a bit.  

For the Sea Horse, the LED is also the LFO indicator (as far as I can tell). Build docs call for a 1K resistor, location R31. Will changing R31 to something more like 10K mess around with the LM324 chip or anything else for the sound?


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## zgrav (Jan 24, 2020)

I don't think dimming the LED by using a higher value resistor will affect the circuit, but try it and see before soldering in whatever LED you choose.


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## Chuck D. Bones (Jan 24, 2020)

Making R31 bigger will have no impact on the LFO or the sound.  Go for it!


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