Although this does not deal directly with mechanical music,
Tchaikovsky's family had an orchestrion (possibly a Welte) that
gave him his first love for music, especially the works of Mozart.
This article, by Michael Wines, is at the New York Times web site:

 Votkinsk Journal: So It Wheezes. It Was Still Tchaikovsky's Piano.
 http://www.nytimes.com/2003/03/03/international/europe/03RUSS.html

If the link doesn't work, I have the article on file.

Randolph Herr