Ultrabright LED, or 3pdt switch?

madstayen · November 18, 2013, 04:19:26 PM

Okay, so with all my gain and boost pedals I get this scratchy sound, like a turntable (vinyl) scratch, but irregular. Without a 3pdt switch it's smooth, but as soon as the 3pdt is wired in to switch the ultra-bright LED on or off, I get this noise. Remove the wires from the switch, then everything is good again. This is literalllleellelllellyyy diirriivingggg emmemmeee bonkrrreers!!!! I tried different types of wiring, different types of switches, Carling, Fulltone, blue ones, white ones, doesn't matter. So I definitely ruled out that it's not the switch. Then could it be the LED? Maybe not use ultra-bright? Maybe use relay type switching to switch the LED, thus not having a 9V+ on the switch directly. Don't know, but this is making me mad!!!!

peterg · November 18, 2013, 05:03:11 PM

Not sure if there is a difference but are you running the LED power to the switch or the neg to the switch? Usually the neg goes to the switch. Are you using a resistor between the power and the LED?

Seljer · November 18, 2013, 05:48:23 PM

Another thing to try may be instead of switching the +9V of the LED, wire the 9V permanently and switch the ground of the LED

italianguy63 · November 18, 2013, 06:17:02 PM

I use ulta-bright blues on Wah's with no issue. What size voltage reduction resistor are you using? (I use 390 ohm). Do you know the draw (ma) of the LED in question? (mine are 18). Finally, what circuit is this on? I recently had an LED "buzz" that I took care of with the "LED Pop" solution (do a search)- it amounts to a larger and a smaller voltage reduction resistor in series, with an electrolytic cap going to ground between the resistors. Cleaned my problem right up! MC

italianguy63 · November 18, 2013, 06:24:12 PM

Another thought-- if you are using the "stereo jack" trick to isolate the battery ground, make sure the jack and plug are clean.

madstayen · November 19, 2013, 12:30:43 AM

There's no difference if the led -, or led+ goes to the switch first. it happens on all my circuits that has gain or boost, especially with circuits like the boogie etc. i'm not sure about the ma of the led, i will check this tonight when i get home. the resistor i use before the led is a 1k0, but i'm thinking of putting a 2k0 in, just to drop the volts a little bit more. i do use the input jack trick, it is new jacks, so it's clean.

madstayen · November 19, 2013, 12:37:09 AM

The weird thing is that if i wire the circuit without the 3pdt, ie everything is "on", including the led, then there's no problems, but as soon as it goes through the switch, all this nonsense happens. that's why i tried so many different types of switches, just to make sure.

Jdansti · November 19, 2013, 01:37:39 AM

Does it happen with the switch when no LED is attached to it?

Seljer · November 19, 2013, 03:28:12 AM

How about different power supplies or battery power?

italianguy63 · November 19, 2013, 03:30:57 AM

Try the LED pop solution-- http://www.muzique.com/lab/led.htm
It cleans up LED noise too...
MC

madstayen · November 19, 2013, 03:31:40 AM

you mean running v+ through the switch without adding a led? havn't tried that yet. will do tonight and let you know. i was also wondering if it's possible to run the led off the output of the board, shunt it to ground, or will that have an effect on the sound perhaps?

madstayen · November 19, 2013, 03:40:43 AM

The psu is good, i tried my boss psa 240 aswell, same effect. i currently use the spyder, which is superclean, eh, well for sound purposes at least.

Seljer · November 19, 2013, 04:07:20 AM

Hmm, I've typically gotten scratchy turntable like noise when I didn't clean away the flux residue after soldering. Maybe clean between the switch's terminal with a toothbrush and some isopropyl alcohol?

chi_boy · November 19, 2013, 10:05:45 PM

Quote from: madstayen on November 19, 2013, 12:30:43 AM
There's no difference if the led -, or led+ goes to the switch first. it happens on all my circuits that has gain or boost, especially with circuits like the boogie etc. i'm not sure about the ma of the led, i will check this tonight when i get home. the resistor i use before the led is a 1k0, but i'm thinking of putting a 2k0 in, just to drop the volts a little bit more. i do use the input jack trick, it is new jacks, so it's clean.

Just to chime in, I use 12k with superbrights. But that's just me.....

madstayen · November 20, 2013, 12:24:29 AM

i tried the popping solution, http://www.muzique.com/lab/led.htm ,still does the same, and it makes the total resistance before the led 5k09, with no lesser effect. what i did pick up though (Wonder why i didn't pick this up sooner) is that when v+ goes to the switch, it has that scratchy sound when the effect is on, but when v- goes to the switch, it has that scratchy sound when the effect is bypassed. i'm no expert at this, but that sounds like a ground problem, but i will check it tonight.

italianguy63 · November 20, 2013, 06:39:50 AM

It almost has to be. (ground problem). MC

madstayen · November 20, 2013, 02:31:41 PM

@ Seljer

QuoteHmm, I've typically gotten scratchy turntable like noise when I didn't clean away the flux residue after soldering. Maybe clean between the switch's terminal with a toothbrush and some isopropyl alcohol?

Turns out you were right, thus far! I tested the switch (on the bottom where the lugs are) with my dimm, the whole bloody surface is conductive!

Scrubbed it with rubbing alcohol, everything sorted. But this I only discovered AFTER I pulled everything apart. So now I first have to re-solder everything before I can definitely say it is good. For now I will assume that it is!

EDIT: Cleaned all my boosters and gain pedal switches and circuit boards. Working good! Thanx mate!

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Ultrabright LED, or 3pdt switch?