I-Dac or Moon audio 100D

I haven't been pleased with how my system plays classical music. It sounds muddled. It was suggested I upgrade my source. I'm using a Muscial Fidelity V-Dac and an Onkyo NS dock, which bypasses the IPod internal Dac.
It has been suggested that I replace both with the Idac or I just replace the Dac with the Moon Audio 100d.
The rest of the system is a Music Hall 25.2 integrated amp and Focal Chorus 706V speakers. I'm using Belkin speaker cable from Blue Jean and Audioquest Blue Racer II interconnect and Audioquest coaxial cable.
Thanks very much for any insight.