Wadia 15 DAC

I have a Sony SCD-777 SACD player with Richard Kern Mods. I tested last night to add a Wadia 15 DAC.  Optical cable (basic cable from Amazon). I feel really nice improvement.  Much more musical.

I had tried with an OPPO Sonica DAC in the past and did not hear much improvement.

Anyone else with similar experience?  What connection would be best?  Coax, Optical, Glass etc.  (Wadia does not take USB).