Sony introduced the concept of digital audio in 1982, with the belief that all CD players have the same performance. However, qualitative differences between them have been proven. Subsequently, the market saw combinations of transport and DAC, where it was pointed out that all S/PDIF audio cables are equivalent, which was also not true. Today, this perception has evolved. Is digital audio simply 0 and 1? The experience from the Pearl USB will convince you of its qualitative differences.