best way to convert hdmi out to coax or optical for pre amp input

Depending on your model, the DAC in your Oppo should be pretty good.  Have you A/B tested the optical out vs rca out with at else CDs? Is the Parasound that much better? Honestly, I'm not sure if it's worth your effort.  You might be better off buying a used DAC that supports hdmi inputs or selling your Oppo for a player that supports optical or coax out for all supported discs formats. Personally, I'm sick of switching cds so I ended up ripping everything I own and putting it onto a music server.  The funny thing is that I flip more records, more ever now.  I rarely use my Oppo player.  

 hdmi out to coax converters usually aren't reliable and might degrade the sound, You should consider replacing your dac to one that have hdmi input. 

thanks...well, I may just put in a small monitor to start with and see how the output is without any converters