I recently made a volume pedal from a schematic I found on a website. The schematic is here Solo Pro Schematic . I used a bi-color led with Voltage (V) : RED~2.1, BLUE~3.3, and I used the stereo jack in place of the input jack . I also added a dc jack with this diagram dcjack . But when I turn on the pedal the led doesn't work and wont even turn on. I am thinking it is because the resistors are too much to power the led but I dont know so I am turning to you guys for you expert advice. What do you think is wrong?
Last edited by the r3d3m3r at Mar 14, 2009,
Ok I'll try the 1k resistor, but can the polarity of a bi-color led be backwards when each side has a different color of led?
The bi-color LED has a common cathode (negative) and two anodes (positive). The middle leg is prolly the cathode, but test it with a 1.5v battery or something to be sure (no resistor needed if you power it with 3v or less btw).

You could also have wire the dc jack wrong. They have a built-in switch that disconnects the battery with a plug inserted. Did you also check the stereo jack if there is one?
Well, everything works but the LED. But if I'm supposed to test the cathode, which is where the led is grounded then shouldn't nothing happen? And I did wire the stereo jack so when a jack is inserted into the dc jack then the battery disconnects.
You wired the stereo jack how? That didn't make sense.

You test the LED by connecting power between the cathode and an anode. Between the cathode and Anode A, it's red and between the cathode and Anode B, it's blue or w/e.
I wired the stereo jack by connecting the input spot on the 3pdt to the tip of the stereo jack, connected the negative end of the battery jack to the tip, and connected all the grounds to the ring. How would I get 1.5 volts from a 9v tho?
The (-) battery goes to the ring, not the tip. Common ground goes to the sleeve.

Nevermind about the test thing... the reason you put a resistor in series with an LED is to lower the voltage going into it. 3v and under need no resistor.
That should be self-explanatory...

The lug closest to the opening is the sleeve.
Middle lug is the ring.
Lug furthest from the ooening is the tip.

Also, an important note. There are two sets of contacts. The ones you want to use will touch the plug when one is inserted. The others are used as switch contacts. Idk how to explain it...
Alright, Thanks for trying to help me out, even if this stuff was pretty obvious.
Last edited by the r3d3m3r at Mar 16, 2009,