SoloDallas was founded by Filippo Olivieri in 2014 to recreate the Schaffer-Vega [Diversity System]  (SVDS) as used by Angus Young on AC/DC's album back in black. Although the Shaffer Vega was a wireless system it also had boost and compression circuits which Angus used to create the album's distinctive guitar tones. Fil Olivieri e-mailed the original inventor Ken Schaffer asking about  his long-forgotten SVDS & Schaffer gave Olivieri his last two functioning units. With Schaffer’s blessing, Fil hired a team of electronics experts to reverse engineer the SVDS to re-create it in the form of a non-wireless unit, under the company name SoloDallas and the first units rolled out in 2014 – The Schaffer Replica was born.

Source: SoloDallas website (28 March 2022)