Wierd noises with colour-change LED in BYOC reverb

[philbinator1]

Hi guys,  I have this byoc reverb i recently made up...its ok, loses a little volume when engaged...but the main thing is:
I recently took out the stock red led (it had a 4.7K resistor) and installed a real purrrdy colour changing LED with a 330
ohm resistor (i figured through testing that was the best value).  The led is making a wierd whirring noise that goes up
and down as the led cyles through each of it's 7 colours.  any ideas on how to quite this?  It's not really loud, but when i turn my
practice amp up loud i can hearany ideas on how to quite this? it in the background; maybe going through my 120 watt Triple XXX it might be bad...?

it's no biggie I can change the led to a ultra-bright blue, but...any ideas on how to quite this?

[jkokura]

Are you sure it's the LED? Have you tried removing it again or just noticed it after you installed the colour changing LED. Did it work fine with the stock LED (As in you had none of the same symptoms in the same situation?)

I'm not sure what causes this kind of thing, but it's good to know if it 'is' or 'isn't' the LED causing the issue. You might be headed towards a goose chase if it isn't! Or it's an easy fix if it is. Go with a different LED is the obvious solution.

By the way, the BYOC Reverb has sooooo much reverb on tap. I had to mod mine to give me less reverb to make it more usable - involves changing a 33k resistor out, I used 5.1k. I think I'll put a switch in that switches between a 20-30k resistor and a 4.7 or the 5.1k resistor for 'long' and 'short' reverb settings. I like it a lot though - very usable pedal for me.

Jacob

[Scruffie]

I think the circuit in those colour change LEDs can cause the problem you're experiencing, i've heard that the 'slow' versions have less of an issue with it.

[dano12]

Most color changing LEDs incorporate a small circuit that uses PWM to change the color. PWM usually leaks back into the circuit through the power connections, hence the noise.

I think just about everyone who has tried them in stompboxes has had the same issue.

[philbinator1]

Are you sure it's the LED? Have you tried removing it again or just noticed it after you installed the colour changing LED. Did it work fine with the stock LED (As in you had none of the same symptoms in the same situation?)

I'm not sure what causes this kind of thing, but it's good to know if it 'is' or 'isn't' the LED causing the issue. You might be headed towards a goose chase if it isn't! Or it's an easy fix if it is. Go with a different LED is the obvious solution.

By the way, the BYOC Reverb has sooooo much reverb on tap. I had to mod mine to give me less reverb to make it more usable - involves changing a 33k resistor out, I used 5.1k. I think I'll put a switch in that switches between a 20-30k resistor and a 4.7 or the 5.1k resistor for 'long' and 'short' reverb settings. I like it a lot though - very usable pedal for me.

Jacob

Hey Jacob, yeah i'm pretty sure it's the led, was fine before.  maybe it's not that good with audio applications, not sure.  but yeah i did the mod too!  changed mine to 4.7K, and i reckon i could go lower, maybe 3K even.  way too much reverb for me, it was too sensitive.  I actually finished with the build and decided i didn't like spring reverb at all     but i still use it cos i need a reverb, i just have it on around 10 o'clock with the 4.7K in there.  anyway i got the fv-1 build from tonepad, in the process in building that at the mo.

[philbinator1]

I think the circuit in those colour change LEDs can cause the problem you're experiencing, i've heard that the 'slow' versions have less of an issue with it.

yeah it doesn't change too fast, maybe a new colour every 3-4 seconds.  but you can def. hear the motorbike accelerate/decelerate sound with it.  and i
heard it has come circuitry in the led (maybe that's why i had to use such a low K resistor?).  it certainly looks different to normal leds if you look at it
through a magnifying glass.

[philbinator1]

Most color changing LEDs incorporate a small circuit that uses PWM to change the color. PWM usually leaks back into the circuit through the power connections, hence the noise.

I think just about everyone who has tried them in stompboxes has had the same issue.

oh!  well that's good to know actually, better that than some other build flaw of mine     oh yeah whats PWM?

[tiges_ tendres]

Most color changing LEDs incorporate a small circuit that uses PWM to change the color. PWM usually leaks back into the circuit through the power connections, hence the noise.

I think just about everyone who has tried them in stompboxes has had the same issue.

oh!  well that's good to know actually, better that than some other build flaw of mine     oh yeah whats PWM?

Pulse Width Modulation
http://en.wikipedia.org/wiki/Pulse-width_modulation

[deadastronaut]

yep had the same problem..ive found a kids toy with an colour changing led without a chip (black dot)

so might try it.....shame they dont work  without a noise coz they look cool.......and hot!..he he......

[deadastronaut]

ok, old thread but..

was there ever a cure for the RGB colour changing leds noise issue?...just curious.

edit: just tried a 220uf cap in paralell with the led...seems to have sorted it...however the colour change isn't as smooth

it sounded like a cat meeeeeoooowing without it.....quite convincing impression too.

[puretube]

heterodyning with some clock somewhere in the circuit?

[deadastronaut]

nope, just a fuzz face.

[aethertransit]

ok, old thread but..

was there ever a cure for the RGB colour changing leds noise issue?...just curious.

edit: just tried a 220uf cap in paralell with the led...seems to have sorted it..

it sounded like a cat meeeeeoooowing without it.....quite convincing impression too.

Not sure if the OP found a solution or not, but Jack Orman has a diode noise fix on his site that works great for this situation. I originally tried this on a high gain pedal and simply adding a cap in parallel with the LED didn't cut it at higher volume. I ended up using a 1K/10uF/100R combo to the anode and it's quiet as a mouse.

[deadastronaut]

cool, i just tried a few different RGB leds, even one that fades, then flashes and 100uf in para seems to have sorted it..

without that cap it ticks and screams like a .....  .......

no noise at all now...very cool.

i have it all on breadboard at the mo, so thought i'd give it a whirl between coffees..


edit: tried it at full volume...quiet as a mouse too..

[puretube]

heterodyning with some clock somewhere in the circuit?

was meant for OP (byoc reverb...)

[deadastronaut]

^ yep,  just thought i'd post here rather than starting a new thread..