In 2014-2015 I built two Solodallas Towers for Angus Young of AC/DC. These are replicas of the audio circuit of his old Schaffer Vega wireless guitar system that he bought with the band in 1977.

The Schaffer Vega Diversity System (SVDS) was the first wireless ever made for instruments, and had a very special sound. These receivers also contained a clean boost of up to 30dB, which the band soon discovered to make their amplifiers overdrive more.
 

This wireless system (SVDS) can be heard on all albums from Powerage (Highway To Hell, Back In Black, For Those About to Rock ,...) until the system is put away. Since then, Angus has never sounded the same.

For the Rock or Bust album and the tour, Angus wanted his 'old' sound back. We were therefore lucky enough to see the material backstage at their performance in Werchter. On the left you see Trace, Angus his Guitar technician.