Good/bad idea? Oppo in 2 channel w/out preamp?

I'm considering moving on from an Upgrade Co Denon 3910 to a modded Oppo SE or Nuforce BDP-83, probably a Modwright with the tube upgrade. I've just went from an integrated amp to seperates and am using a cheap Parasound mini-preamp until I can either have a good passive built OR get a player with built in volume control. I've mostly had very good success going without a preamp when possible. I've had a Theta Miles and Consonance Droplet 5.0 which were much better without a preamp while a Consonance SACD 2.0 was a bit tubby and less precise direct (it sounded quite a bit better using the passive preamp section in an integrated I used to own vs running that integrated as an amp only).

So, can anyone comment on running the BDP-83 SE or Nuforce direct into an amp and do any of the aftermarket upgrades affect the quality of the volume control? Many thanks for your time and experiences. Lyle