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Flashing LED

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captainate

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Hey all,

I'm building a tremolo pedal for guitar (and Rhodes), and I just about finished before I realized there's a problem. The audio path seems to be fine (can't test it just yet), but the LED modification not included in the original schematic is giving me an issue.

I am trying to use the modifications found on page 2 and 3 of the attached material, and add an indicator light to the "boost only" switch (dpdt instead of spst). The problem is that I don't know what the value of the included LED is in their kit (I'm building just the PCB), so I don't know if the recommended 10K resistor is part of the flashing circuit or the standard resistor for the positive side of the LED. To be clear, I don't need a special LED, right? It's supposed to flash with the speed of the tremolo, so it should be affected by R14, the 100K C pot.

The root of the problem is that the wiring diagram is so crowded I can't tell which pads the resistor is supposed to connect to. Also, the LED I'm using needs a 215 Ohm LED in the standard 9-volt series configuration, so why would theirs need 10K?

I'm in over my head. Thanks for your help, and if it's useful the original schematic is also attached.
 

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  • ggg_eat_mods.pdf
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  • ggg_eat_sc_improved.pdf
    184.1 KB · Views: 145
I'd go right back to General Guitar and ask for this modification shown on the schematic as opposed to 47 lines criss crossing a dense PCB. They spent a lot of time generating a terrible sketch. They will know what LED to use and how it works with a 10k resistor.
 
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