The popular SansAmp PSA-1 underwent an internal redesign and is now known as SansAmp PSA-1.1. While the 100% analog signal path and functionality remain the same, during the design process Tech 21 was able to include a few new features: an on/off switch on the front panel, more program locations (there are now 128), a master volume control, an XLR ground lift switch, phantom power MIDI input, and a dedicated headphone out.