I cannot answer to your specific issue as your existing system is, in many components, better than mine. I will limit myself to commenting on your inexpensive Sony Blue Ray player.

Late last week my OLD Toshiba DVD player died in my video system in my living room. I had it parked above my cable companies DVR and that thing runs HOT. As I was way over my audio/video budget for the quarter, I simply replaced it with an inexpensive Sony DVD player. It played DVD's well but, its treatment of CD's was worse than my iPOD playing WAV files through the same system. I dug out a VERY old Audio Alchemy DAC I had left over from the 90's and hooked it up...That well made 15 year old DAC sounded WAY better than the DAC in the DVD player so...do something about the digital source...it will be your biggest improvement for the buck IMHO.

How about this. It's got tubes. It functions as a headphone amp and tube buffer. It also has 5 inputs. Run the digital out from the BluRay to it for 2 channel.

Grant Fidelity Tube DAC-09 Digital-to-analog Converter - MSRP US$300.00 selling price $225