Schaffer-Vega Diversity System

The Schaffer-Vega Diversity System (SVDS) was a wireless transmitter system used by Angus Young from 1977 through the early 1990s, and it became a secret ingredient in AC/DC's guitar tone. Far more than a cable replacement, the SVDS added compression, midrange boost, and harmonic saturation to the signal chain — essentially functioning as an always-on preamp that fattened Young's Gibson SG through his Marshall Plexi stack. The difference was so pronounced that AC/DC's live sound and studio recordings from this era have a distinctive thickness and sustain that engineers struggled to replicate without the unit. The original units are extremely rare. Schaffer Replicas began producing faithful recreations in 2015, endorsed by Angus Young himself, making the SVDS tone accessible for the first time in decades.