LED voltage for a 301 Flanger

[peterg]

I'm working on the layout for a 301 Flanger and am wondering about the placement of the LED reisistor. The input voltage for the circuit is 18 volts which is dropped to 12 volts via a voltage regulator. The voltage into the pedal is 9 so I'm building a MAX1044 voltage doubler. The pedal has 9, 12 and 18 volts available to run the LED. Can I use the 12 or the 18 or do I need to stick with 9?

[mth5044]

The LED's will be able to take any of the voltages, it's the current you have to worry about. There are a ton of online calculators that will help you determine what resistor value you need based on the V, amps, forward voltage, etc, that you can get from the datasheet for the LED (or guess based on it's color).

I'd use the source that has the most mA avaliable. The MAX1044 can only put out a couple dozen mA, all of which you will likely want for your flanging. The 12V will also be limited since it's only using what the MAX1044 can give it. It is likely the 9V will have the most mA to use.

[peterg]

Thanks Matt