Also my first CD player, or music player in general (never had a record/tape player before this either). I was quite fond of the fact that I was part of this new CD music era.
For the longest time, I didn't really have many CDs, so I'd play actual Turbo CD games in there as musical CDs (Cosmic Fantasy 2 or Ys Book I & II... Loom had a bunch of Tchaikovsky tracks). My only headphones were the old ones that had come in a travel-pack with my original Gameboy, but I had a set of computer speakers that had been discarded in favor of powered ones I used alot.
I felt very clever and high-brow having that computer speaker + NEC "portable" CD player setup when we went out to our remote ranch house.
Good times, but I think ye olde drive was burned out by a couple years after the Duo came out from all the use.