image courtesy of Kevin Lightner
The PPG EVU is basically a rackmount Wave 2.3 with no keyboard, LCD display, or analog control panel. As it's name
suggests it is an expander to be used in conjunction with a Wave synthesizer or Waveterm computer. The EVU is an 8 channel
module. Each channel has it's own volume and pan controls plus an individual output. The unit also features a master volume
control plus left and right master outputs.
The multi-function LCD display of the Wave is replaced in the EVU with a large two-digit LED display. Similarly, the separate
numeric and function keypads of the Wave are condensed into a 20-key keypad in the EVU. MIDI and cassette interface jacks
are positioned on the rear panel of the unit.
The EVU was designed to be able to load 8 different samples or wavetables into memory, and therefore to be multitimbral. This
was a big development before the Wave 2.3, being that the 2.2 could only hold one sample or wavetable in memory at any one
time. Eventually the advantages of the EVU were added to the 2.3, making them essentially the same in most respects.
Originally the only way to communicate with an EVU was through PPG's proprietary Communication Buss. Later, when MIDI
was added to the operating system, the EVU could be used in a more stand-alone fashion. In fact, with EVU software version
3.0, system exclusive commands were added. This allowed more complete control via MIDI.
[excerpted with permission from the PPG page atAntarctica Media courtesy of John A Trevethan]