The JIMDAC is a really basic converter; CS8412 and TDA1541. Just like everyone else is doing. But with a Hagtech twist. I take it to the next level by adding a discrete front end receiver, super-regulators, no series capacitor on output, passive Bessel I-V, noise reduction, and a world class layout. Much of it is not obvious. Two chips are for super-regulators.
No parallel DACs. I don't like that solution, as it will only add time smear and unhappy interactions. Other folks do it to get more output power. Not me, I push the output voltage as low as possible. Hence, JIMDAC will have linearity that far surpasses other designs using the same chip. Again, much of this is not obvious to casual observation. Oh yeah, the 5th IC is an opamp for voltage gain and buffering.
The diyparadise dac looks quite nice, but they made a mistake with that ferrite bead. Such is very common with inexperience (you will see this a lot in DIY). With a tube amplifier it will sound just fine. Or any system that doesn't mind ultrasonic and RF crap on the audio lines.