The device can utilize both stock and third-party impulses in WAV format. All the needed folders are automatically generated on the microSD card upon initial use (those folders are SD:\SL_IR\A\ and SD:\SL_IR\B\). In order to replace an impulse, simply delete the old one from one of the folders and place the new file into the same folder. For instance, to replace impulse A, go to SD:\SL_IR\A\ and replace Sunn_200s.WAV with an impulse file of your choice (required format: 24bit 48kHZ WAVE PCM1, uncompressed). Next, insert the microSD card into the Olympic MkIIIS and set the CAB switch to A in order to hear the new impulse. When no microSD card is inserted, the Olympic MkIIIS uses built-in impulses. This way, you can extend your impulse pool to four or pair a stock impulse with a third-party one on the microSD card.
In this mode, the Olympic MkIIIS will apply the built-in neutral power amp simulation to any impulses you upload.