These days, API 500-format modules are available in all kinds of configurations, including stereo. However, for a long time, only mono modules were available. Some of these modules allowed for stereo operation with some very simple “surgery” — jumping two pins together. For example, the API 527 includes a “link” switch that with the jumper mod will let you link two compressors together.
To do this, you’ll need to be comfortable with using a soldering iron, but it’s very basic soldering, nothing complicated. First, make sure your API Lunchbox is empty, so it’s easier to get your hands in. Looking at the Lunchbox motherboard, you’ll notice each slot has a solder pad labeled “Pin 6.” Simply solder one wire from pin 6 of the slot where you’ll install the first module, to pin 6 of the slot where you’ll install the second module you want to link in stereo (preferably right next to each other, if possible).
That’s it! The mono modules installed in those two slots can now use their built-in stereo link feature. Note that this will not allow you to create a “stereo” module out of two devices that are not already built to accept stereo control, such as the API 527. Also, you may find that different modules require different pins to be jumpered together. But regardless of the specific pins, the process is always the same — solder the jumper between the two slots and your two modules are linked.
[NOTE: Perform this and any other modifications at your own risk. Sweetwater is not responsible for any damage, injury, or problems resulting from attempted modifications. For best results, have a professional technician perform the modification for you.]
