And the first review is out, more to come https://youtu.be/C0nQ2uehI08
We are using one of the class AB chips from the TI's Overture Series.
LM3866 is a fine chip with more power, but I felt this other one offers superior sound - superior enough to sacrifice output power. I think I posted this in one of the earlier threads... the Spark was not a planned product, as I was testing various chips for a different application; however, I liked the sound of this part so much that I decided to make a product out of it, even though I knew that its low power would make it a niche. So I streamlined design, made it clean and straightforward (no bells and whistles), thinking: "if it's niche, let's shoot for the best in the segment".
Turns out, it's not so niche - by now we have a good collection of speakers that love the Spark and they are of various types, sizes, sensitivities and price ranges.