Im trying to play HDCD encoded files to My Cary 303/200 but they dont seem to be recognised bythe Cary as such. Im Using the HDCD plug in for foobar. When i put in an HDCD CD the HDCD light comes on on the Cary. However when i run the ripped file hrough the spdif into it the light doesnt come on.
Not sure if its just not passing the hdcd signal(set at 24bits/96khz default in HD Audio manger, at 16/44 doesnt help get hdcd) or if the Cary will only recognise HDCD from a disk.

HDCD is a format that "magically" encodes 20bits of data into 16bits. There is a signal bit in the stream that identifies it as HDCD. If the decoder takes the HDCD data and converts it to 24/96 the player has no way of knowing that the original source was HDCD. If you configure Foobar to pass HDCD PCM unmolested to the player then the light should come on. Although depending a how/where the HDCD decoding is done in the player that light still may not come on when not using the physical disc. HDCD 16bit PCM can be played just fine without decoding, just slightly lower SNR.
The plug-in only partially reproduces the full HDCD decode. If the Cary does the whole process you may be better off turning off the foobar decoding. As Larry says, that should let the original signal pass to the Cary and the Cary can do the proper decode.
Without decoding dynamics might be lower and data will be only 15 bit since bit #16 is used to switch dynamic range.