Au20

Series was released by Rykodisc between 1993 and 1997. In all, thirteen titles were released (one Richard & Linda Thompson, eight David Bowie, two Mickey Hart and two Frank Zappa titles), in addition to the David Bowie box. The advantage of a gold reflection layer on a compact disc is its corrosion resistance. All thirteen titles had previously been transferred from analog tape to digital tape. In the Au20 series, the digital master was transferred anew from the original 15 ips stereo master tapes to 20 bit masters. This audio was then transferred using a Sony Super Bit Mapping (SBM) filter to 16 bit PCM. As with all gold-layer CDs, the disc is encoded using Redbook standard 16-bit/44.1 KHz PCM mastering. Aside from corrosion resistance, designation as a gold disc is a marketing term. Note: Rykodisc used the new remaster on some 1996-1997 pressings of non-gold titles (Hunky Dory and Changesbowie, according to former Rykodisc employee Jeff Rougvie).