For the record, here's how you do a factory reset on a Sonance DSP 2-150 (and probably other DSP amps):

Use a small flat bladed screwdriver to set the left channel front gain knob all the way counter-clockwise. Turn the right channel front gain knob all the way clockwise. Make sure they are fully against the stops.

Power the amp off for 20 seconds. Power the amp on. You should see the channel lights go red then green, then the main power light blink then the channel lights change some more. After 2 minutes, power cycle the amp again. It should now be factory reset and in DHCP mode.

This one was still not showing up on some network scans (angry ip and windows) for some reason, but fing saw it and it seems to be working fine.