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Projects => Tech Help - Projects Page => Topic started by: 2tonewarrior on March 26, 2012, 07:15:27 PM

Title: Multicolor led weird sound
Post by: 2tonewarrior on March 26, 2012, 07:15:27 PM
I´ve build a Serendipity. The sound is very good in general but when the multicolor led changes his color it sound a weird beep. Here is a video with the problem:



Sorry for the crappy quality, I only have my mobile to record.


The only thing i´ve changed regarding to the project is the orientation of the led (same problem as here http://www.madbeanpedals.com/forum/index.php?topic=55.0) and one capacitor from Film/Foil to ceramic (I don´t know if it is relevant)


BTW here is the led i´ve used: http://www.banzaimusic.com/LED-5mm-RGB-multicolor.html

Hope you can help me :)
Title: Re: Multicolor led weird sound
Post by: k.rock! on March 26, 2012, 07:50:32 PM
Add a 33uF electrolytic (or any other polarized cap) in parallel with the LED. I believe you need to put it in opposite polarity with respect to the LED. Like this:
 
                    LED
(long lead)   ---|>|----  (short lead)
                |            |
------------|            |----------
                |            |
                ---|(------
                    cap

If it helps but u can still hear it, then increase the capacitance.

Here's a build report I did a long time ago with a color changing LED. You can see the cap across the LED.

http://www.madbeanpedals.com/forum/index.php?topic=1074.0



-K
Title: Re: Multicolor led weird sound
Post by: 2tonewarrior on March 26, 2012, 09:11:04 PM
Quote from: k.rock! on March 26, 2012, 07:50:32 PM
Add a 33uF electrolytic (or any other polarized cap) in parallel with the LED. I believe you need to put it in opposite polarity with respect to the LED. Like this:
 
                    LED
(long lead)   ---|>|----  (short lead)
                |            |
------------|            |----------
                |            |
                ---|(------
                    cap

If it helps but u can still hear it, then increase the capacitance.

Here's a build report I did a long time ago with a color changing LED. You can see the cap across the LED.

http://www.madbeanpedals.com/forum/index.php?topic=1074.0



-K

Thank you, I´ll try it tomorrow. Could I start with a higher value? I have some electrolithycs here in my house but no 33uf.
Title: Re: Multicolor led weird sound
Post by: k.rock! on March 26, 2012, 09:33:08 PM
Yeah, I mean you can certainly start lower too. I only said 33uF cause that's the value that worked best for me.

-K
Title: Re: Multicolor led weird sound
Post by: 2tonewarrior on March 29, 2012, 10:58:33 AM
Sorry for the late reply, I´ve been busy.

Awesome results, thanks for the help! The first I´ve tried (220uf) completely eliminates the annoying sound, but I´ve got a doubt. Should I keep looking for the best capacitor value? I mean, does it affects the sound in some way? or if it just works doesn´t matter?