What gives the RMI piano that 'crunch'?

[publicradio]

I have an old RMI piano VST, and I'm pretty happy with the sound. But one thing I hear on RMI recordings that I don't here on the VST is this kind of ring modulated, bitcrunched sound that's subtle on some records, and really pronounced on others like .

I can get this sound by tweaking a bitcrusher plugin, but I wonder how an analog piano generates what sounds like digital degradation. I also wonder why it's heard in some recordings and not in others, when it doesn't seem like there's anything in the controls for this.

[CHOOS]

It's not necessarily bitcrushed.
Some might help but you're looking for lo-fi effects and Wow & flutter effects.
izotope vinyl = free and awesome
but google a few more. The combo of two or three might do wonders