@big_greg is right.. The first SACD's were 2-channel only. They only had a left and right analog out and usually one digital out for pcm on cd playback. And the first discs were only two channel. Only DVD-A was multi channel for a very long time after that. I sold them both in '99
We are debating whether the chicken or the egg came first (players or the media they play) back 25 years ago. But what actually came first was the DNA or essential blueprint, the Scarlet Book which defines the multi-channel format.
If Sony, in its rush to be first, decided to only use 2 of the 6 available channels, so be it. The unit they submitted to Gramophone for review came with a Japanese demonstration SACD which the reviewer found shrill and harsh.
The August 2001 review by Andrew Everard noted the Philips SACD1000 was the first machine able to play multichannel discs, a step towards making SACD a mass-market medium.
The subsequent October 2001 issue featured a dedicated review column for "Multi-Channel SACD Reviews," which covered the playback experience of 13 multichannel SACD discs using a Sony player and surround sound speakers. Reviewers noted that well-executed multichannel recordings added a significant dimension to the listening experience compared to stereo versions.

