It seems that most all the M-Tron sounds (with exceptions like the cello) have much poorer signal to noise ratio than the real deal. I don't recall the Moodies or Crimson Mellotrons sounding hissy in unflattering ways. Mr. Dickson's recordings certainly don't sound that way.
My recordings were filtered track-by-track through a very good noise reduction system indeed to eliminate the white noise overhead. Pile up 40 tracks of that and it would swamp everything. The thing is that what you record on Monday has a different sonic picture the following day. They are such fickle creatures.
I just don't much care for the M-Tron sounds. They seem muffled to death at times and some appear to have been recorded with a mike at the Mk II speakers. I mean...there is 'authentic' and there is 'needlessly hopeful'.....
Mike