Eddie was seen using this tape echo in the early days, together with an Echoplex EP-3 – which is a tape delay. Sometimes he would he two Univox, sometimes one, and they were usually mounted in a World War II–era practice bomb that was repurposed as a rack.
Something to add would be that the Univox was used to execute the octave dive on the end of “Eruption”. Also, the reason for two Univoxes was for backup purposes. Ed had two of almost everything except the phaser and flanger in his 1978 rig to always make sure that he didn’t get into trouble.