John Grandberg has posted a review of the Parasound Zdac ($475) at Inner Fidelity. His conclusions:
“In summary, the Zdac looks, feels, and sounds like it could be a $1000 unit. It certainly didn’t feel out of place in my rack with numerous competitors in that range. As a DAC, the Zdac offers exemplary performance with practically zero downside unless we count the lack of support for sample rates above 96kHz. As a headphone amp it could use a few tweaks, but still manages to sound excellent with the right headphones. Do I recommend it? Yes! Rather strongly at that.”
You can read the full review here.