Your Luxman integrated deserves a quality digital front end, if your DAC is on par with the Luxman, purchase as follows:
ADOT MCO1 fiber optic kit
LHY 25A LPS with dual 5v outputs
Uptone Audio EtherREGEN switch
Audioquest Forest ethernet cables
Lumin U2
The Lumin alone is a significant upgrade over the iFi Zen, but coupled with this chain, the sonic gains can be huge.
How do I know this? Because every single step I mention above I have done in both my home and office systems, with fantastic results.