Von hier: http://www.naturalrhythmmusic.com/diy.html und schaut so aus: Do you like blinking LED's? Do you wish your modular had more of them? Great news, build the following device to monitor voltage in your baby. All you need is a 560 ohm resistor, a bi-polar LED, and a jack (1/8" will work too of course, but not banana ha ha ha ha!, J/K Banana-Gang, I have love for you too! Pssst... but it still won't work for you). Simply solder the resistor between the LED Anode and the Hot tab of the plug you are using. Voila, instant bi-polar LED indicator. Great for VCA outs, LFO's, CV monitoring of all sorts. Can't remember where I saw this before and learned it so thanks to that person. I have a handful of these I use off and on.