Everything else in the system being the same... same room, same calble, same power supply, same ambinet temperature, etc., I am not sure how anyone can play a CD on a std. CD player and not hear a pretty decent difference between that and a nice DAC.
Once you take away the spinning disc itself, motor, laser pickup, power supply noise, jitter, etc. and just send data to a DAC and let the DAC do its thing, you will have a big difference ion sound. Not with all DACs... if you are still connecting to a DAC with USB, toslink, etc., you are missing out still. The LINN DS units connect to your network via CAT5 and just send "data" to the DAC for it do "go to work". If you are using a PC, laptop, etc. and a connection like USB or wireless to some other device, then through a cable, you are missing out.
My LINN Akurate DS will compete and usually sound better than CD players in excess of $10k. Not to mention that my entire library of music is at my fingertips via and iPad.