May I recommend the following web sites.  John R.T. Davies was not only
a master of the art of remastering from 78 but also a fine jazz musician.

  http://www.bluesworld.com/JRTDavies.html
  http://www.jazzrescue.com/faqs.htm

There is also a useful discussion of this topic in the UK Vintage Radio
Forum:

  http://www.vintage-radio.net/forum/showthread.php?t=6825

Jeffrey Borinsky, London, UK