Welcome to the Sinatra Family Forum, Richard!
(You're not our first Rich from Philly, but the other one goes by the name "voice1." I suspect you'll hear from him shortly about patent infringement or some such.
The thread for the US Capitol box sets may be found here in Frank's Recordings: Capitol Concepts 16-CD Box Set
The original Concepts
box, released in 1992, was exactly that: a wooden box. You can find some photos of it near the current end of that thread. This was simply a packaging device for the 16 contained CD's, which also were sold individually and had been released between 1987 and 1991 (except the instrumental Tone Poems Of Color
, which was available only in the box set). These CD's were mastered by Larry Walsh; they are long out of print.
The later black cardboard box set (shown in the lead post of the referenced thread) contains remastered versions of the same albums, with the identical song lists and bonus tracks. This was released in 2000, and the mastering was performed by Bob Norberg. The discs in this package are digitally identical to the current individual Capitol CD's (from 1998 to 2002), which contain the "Entertainer of the Century" logo and are labelled as "20-bit" or "24-bit" remasters.
Most people do believe the EARLIER set of discs have BETTER sound, although not nearly as good as the original Capitol LP issues. You will find many discussions about this elsewhere in the Forum. (Give a yell if you can't find those yourself, and I'll dig up some links for you.)