I recently purchased this set on Ebay still sealed. It just seemed like a pretty cool collector’s item. I don’t know if I dare open it. Would the sound on these be any better than LP or CD? I’d really like to have these transfered to find out.
Depends on the tape speed and how well the duplication process worked (high speed transfers, I imagine, perhaps not so good). If middle tape speed, I would guess part way between cassette and LP. The tracks on these tapes are fairly narrow which does not help either. Ageing might cause further losses and print through (creating faint echoes due to tape being pressed against itself in storage). Also, it would pay to get advice from someone who knows about this stuff at an advanced level as old tapes have been known to strip themselves on a single play (see “baking” suggestion in an earlier post - something I would not try by guesswork).
It also depends on the machine you play/record it from. Ageing is defiantly a factor that can contribute degraded tape, but I have cassettes that are 30 years old and they still play efficiently. Tapes manufactured in the 70s/80s are known to last but it all depends on how its stored and if its stored in appropriate conditions. And most importantly, if its well away from magnets.