Why a separate DAC?

@simao - I have the Yamaha CD-N500 CD Player, 192KHz/32-bit Burr-Brown DAC with Ethernet port for connection to network.
@ mike_in_nc the  Audiolab AAV-MDACPLUS Digital Audio Converter Pre-Amplifier looks interesting, but as everyone has indicated. best to try before I buy ! @ adg101 room treatment is not an option as my wife wants me to keep my system in the living room ro she will never see me (her words :-) ) so I will have to live with the decor. As for my system; Cary Audio LSI-80 Tube Amp, Chinook Phono pre Amp, Linn Sonedek LP12 turntable with Fritz Carbon 7 MkII speakers and  Kimber PBJ cables to system with Cullen speaker cables. Just learning about the new digital world and agree that there have been many updates to the technology. Thanks everyone for your repsonses. 

@gdrnBob I agree the DAC technology is changing quickly. I believe that I can use the Yamaha CD as output to DAC. @soix I really appreciate your advice on the try and buy. Thanks!

I would like to thank everyone for their input, for someone who has gone from the solid state to tube experience with multiple amps and is now on the digital journey it looks like I will try to get a 30 day trial for the Mhdt Labs Orchid R2R NOS DAC! Will let everyone know how it works in my system. 

@Jeffseight I would love to be there but I am on the other side of the US! @WC1 thanks for your input. The Fritz Carbon's are about 87db sensitivity, great speakers, amazing reviews cuts out the middleman selling direct. Overall system is very revealing in terms of dynamics, soundstage, etc.

@tube444 I tend to agree with your comments and others; when looking to buy new components within your existing system it is best if you can try and buy but just as good buying the best gear within your budget...used. I have read great reviews on MYTEK LIBERTY DAC and others and will probably buy used. Dont have a lot of places in my neighborhood to try and buy....thanks again.