Total posts : 45366
When I read your post with your reply to my question it got me thinking. Since the power supplied to the SSTRAN units is AC and feeds a full wave bridge, neither of the wall wart secondary AC lines can be grounded to the circuit ground as would happen if the audio ground and one 18VAC line were tied together at the electrical stake since the circuit ground is on the output side of the bridge. Each half cycle, each 18 VAC line will be above gnd. potential. So, it appears that we should NOT do this.
I was thinking of a DC feed and should have realized this is not the situation with the SSTRAN unit. Do you a agree?