The SansAmp PSA-1 features a silver enclosure made of aluminum and steel. The knobs, buttons and handles are black. The PSA-1.1 features a silver enclosure made of aluminum and steel, but the knobs, buttons and handles are also silver. The PSA-1 measures 19 inches by 5 inches by 1.75 inches and weighs 9 pounds. The dimensions of the PSA-1.1 are the same as the PSA-1, but it weighs 5 pounds.
The PSA-1 and PSA-1.1 provide analog sound. All of the effects modify your sound through analog circuitry. Both units allow you to store and recall your presets digitally and via MIDI. The controls on both units include "Pre-Amp," "Buzz," "Crunch," "Punch," "Drive," "Low," "High" and "Level." These controls are accessed via the eight knobs on the front of the units and shape the tone of your sound. The SansAmp PSA-1 and PSA-1.1 offer two 1/4-inch inputs and two 1/4-inch and XLR outputs that can be used simultaneously. An optional footswitch, which can access saved presets, is available for both units.
The PSA-1 does not include an "On/Off" switch. The PSA-1.1 includes an "On/Off" switch on the front of the unit, making it easier to turn the unit on and off.
The PSA-1.1 offers an increased number of locations in the memory for saving user-defined presets. The PSA-1 offers 49 user-definable locations, while the PSA-1.1 offers 77 user-definable locations. This allows you to save more custom presets to memory without the need to override your old presets or factory presets included with the unit. Both units offer 49 factory presets.
The PSA-1 does not feature a "Trim" knob anywhere on the unit. The level of each preset is determined individually according to the setting of the "Level" knob when the preset was saved. The PSA-1.1 features a "Trim" knob that allows you to set the master volume of your sound. This makes it easier to switch between presets without worrying about major shifts of volume. The current setting of the "Trim" knob applies to all sounds produced by the PSA-1.1, regardless of the active preset.
The PSA-1.1 includes an "XLR Ground Lift" switch, while the PSA-1 does not. The "XLR Ground Lift" switch connects and disconnects the XLR output on the unit to the ground circuits. This feature aids in noise and hum reduction, as ground loops and equipment not connected to the same ground circuit as the PSA-1 tend to produce noise.
The MIDI input on the SansAmp PSA-1 does not provide phantom power. The PSA-1.1 provides 10 volts of phantom power through its MIDI input. Use the phantom power to power up the SansAmp MIDI Mouse foot-controller, which is an optional accessory that controls the settings of the unit, including the active preset.
The PSA-1.1 includes a dedicated headphone output, while the PSA-1 does not. The headphone output is located on the back of the PSA-1.1. The headphone output features a 1/4-inch socket that provides stereo output. Use a stereo 1/4-inch cable when using the headphone output to monitor your audio via headphones.