In yesterday's post I told the story of how we jumped into digital audio by replacing the analog output stage of a CD player. Off the shelf, Sony and Philips simply threw in a NE5532 chip op amp and called it good.
5532s are good and we've used them in many applications of PS products over the years. They are just not good in all applications. In particular, as DAC outputs. Much better (at the time) to design our own discrete stage specifically tailored to reduce the digital glare and enhance the good bits.
But, as I mentioned yesterday, as we were learning about these new fangled machines playing those silver discs, we noticed a lone RCA connector on the rear of the CD player. It was labeled Digital Output. What was coming out of that? Hard to know because, in 1982, the only information available was locked up in an industry book known as the Red Book. The Red Book told all but was not made public until years later.
We were on our own and so we began reverse engineering the datastream. Our head engineer at the time, Mark Merrill, poked around and experimented with different decoding ideas for a couple of months—almost giving up more than a few times. Heck, none of us were even certain there was music coming out of that port. It's stated function was the delivery to an aftermarket box that would sit atop your television and display cover art of the CD you were playing.
But, I pushed him. I was "convinced" there must also be music and I was convinced of that because you could see on the scope changes in the datastream that seemed to follow the music.
And then a breakthrough. mark came to me smiling like a Cheshire cat. He had broken the code and we had music playing, running through his homemade circuit he called a Digital To Analog Converter.
Bingo! I decided then and there we would put our company resources into developing a separate audio chassis in our line, one we would call a DAC and one that eventually was named The Digital Link.
6 months after we debuted this unique product category to the high end, our fellow manufacturers launched their own versions (not based on ours as they too had the exact same ideas independent of ours).
Just a bit of history in what has turned out to be 50 years of innovation for PS Audio.
