LEd color impact?

Dali

Well-known member
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)?
 
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.
 
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
 
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.
 
I got a bag and of cool colour changing (RGBY) ones from a similarly unknown source, they’re pretty sweet!
 
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...
 
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!
 
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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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?
 
Sounds like a cool effect using the transparent pot shafts. Was it easy to see in a lighted room? Better in a dark environment?
 
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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