I recently started investigating a rebuild of my Mason & Hamlin Ampico
grand.  It has the original strings, hammers and action with very
little done to it since 1924.

I had a highly-regarded piano technician evaluate the piano to advise
me on what should be done.  He told me that most of his clients like
a brighter, more aggressive sound when they rebuild a grand piano these
days[*].

I told him that I wanted a rich, mellow sound, not an overly bright
one, so he advised me to contact Ray at Ronsen Piano Hammer Company.
Ray told me that the best choice of felt to retain the original sound
of the Mason would be to make the hammers with felt from the Bacon Felt
Company.  To quote from the Ronsen web site:

  "This dark toned hammer at the beginning develops its complete beauty
  with play in time.  A beautifully rich and silky sound. Excellent for
  bright acoustic environments.  When needed it will also respond to
  traditional Steinway type tone building protocols but without the
  usual strong solution of hardeners.  A very versatile hammer choice.
  The favorite of many rebuilders and a perfect substitute for the New
  York Steinway hammer."

Larry Kerecman

 [*] Editor's anecdote:  Each year I would join the jazz band at Mike
 [ Cogan's Bay Records Recording Studio in Alameda, California, which
 [ specialized in recording acoustic groups.  The first few years
 [ I played a Steinert & Sons parlor grand with a distinctive, jolly
 [ sound, and then it was a big, white 7'6" Kawaii grand which I really
 [ enjoyed.  But one day the Kawaii was replaced by a Yamaha C7D with
 [ the ubiquitous piercing Yamaha tone.  "What happened, Mike," I asked.
 [
 [ Cogan replied, "Too many times a student pianist from one of the
 [ colleges would say, 'The Kawaii is a nice piano, Mr. Cogan, but I'd
 [ really prefer to record on a Yamaha grand.'  The rental fees were
 [ killing me so finally I gave up and traded for the C7."
 [
 [ I concluded that the college kids were effectively brain-washed to
 [ believe the hard hammer Yamaha tone is "the best", with no regard
 [ for the mellow sounds available in pianos built before the 1950s.
 [ I call this influence on piano fans "The Yamaha Effect".  (I think
 [ it's related to "The Horowitz Sound"!)
 [
 [ Robbie Rhodes - pianist & MMD editor