Maybe this has something to do with it...
"The dynamic range of an audio system is a measure of the difference between the smallest and largest amplitude values that can be represented in a medium. Digital and analog differ in both the methods of transfer and storage, as well as the behavior exhibited by the systems due to these methods.
The dynamic range of digital audio systems can exceed that of analog audio systems... An LP made out of perfect vinyl would have a theoretical dynamic range of 70 dB. Measurements indicate maximum actual performance in the 60 to 70 dB range."
and,
"...the dynamic range of a 16-bit / 44.1 kHz CD is over 90 dB — slightly greater than the range of human hearing."
Is it possible that you need to turn up the volume on your analog source to replicate what you typically hear from your digital source?