Looks like a 7824 in the PSU.
Complete manual and schematics here:
https://www.dropbox.com/s/xetnx0pq4s8c00j/ADR%20F769X-R%20Vocal%20Stressor.pdf?dl=0
And an addendum here:
https://www.dropbox.com/s/0s83rs97aibworh/Vocal%20Stressor%20addendum.rtf?dl=0