So, a “Bitstream” recoring.
1-bit DACs had been around since about 1988ish.
BUT … I don’t recall ADCs way back then that were using 1-bit technology?? I assume all digital recordings at this time were PCM.
In the early days of CD, finding one that was a DDD meant you told two people, and so on… We just assumed that was the best. Now I’m thinking nearly everything is. But these days it’s all heavily compressed. In those days not so much.
In the early days of CDs, I had a few marked DAD. Like @aangen, I kept a list. DAD was a real oddity back then, but, alas, my list is long lost and I can’t remember the titles.
On a slightly related note, these early Hyperion discs were mostly made by PDO UK and were prone to disc rot. I’ve read so much misinformation about this online, but many moons ago an archivist told me about these early PDO UK pressings and he said to keep the booklets away from the disc and I’d be fine. He explained that the sulfur in the paper booklets penetrates the weak disc coating they used. In truth, by keeping the booklets away from the disc on these early PDO UK pressings, I’ve never experienced disc rot with these. Of course, this wasn’t limited to Hyperion. PDO UK pressed many early CDs. I keep the booklets away from all of them.
In defense of Hyperion, they would, back in the day, replace a rotted disc with an improved, non-rotting pressing if you sent them the CD. I had some friends who did this.