Increased filter range for Juno-66

Due to popular demand there is now a hardware update for the Juno-66. It increases the range of the filter control, which also allows larger amounts for the additional filter ADSR, Tri-LFO and SH/LFO. The range is increased by a factor of three.

We now ship the Juno-66 with this modification, it is however relatively simple to perform and can be done by a skilled solderer and any synth tech. This is how to do it.

The modification consist of two parts: Changing a resistor on the Juno-66 board and changing one of the capacitors you installed as part of the Juno-66 install.

Parts needed

  • 100nF through hole ceramic capacitor
  • Resistor: 20k 0603 or 24.9k, 24k or 22k resistor of your choice (see below)

Changing the resistor

Warning: If you break the Juno-66 while performing this modification it is your own responsibility. Take especially great care while removing the Juno-66 from its socket. The pins can break if too much force is applied. The best way to remove the Juno-66 is to gently pull it out of the socket on one side – but not the whole way, just a tiny bit. Then pull on the other side and repeat this until it is out.


You need to change the value of the resistor marked above to 20k. You can either desolder it and replace it with a 20k resistor, or solder a 22k resistor in parallel. (22k gives you a slightly small resulting resistance of about 18k, if you can use a 24k, or 24.9k). These are 0603 SMD resistors, but it should be possible to solder a through-hole resistor across it.

Changing the capacitor

This is much easier.
All you need to do is to replace the 10nF or 3.3nF capacitor which you installed during the Juno-66 installation with a 100nF one.


That is it, enjoy your increased filter range!