damper problem (probably just stupidity on my part)

[Farrell]

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Looks like you've gotten some good responses so far Tom. Others have =
pointed to spring tension, backscale ringing, and poor original damper =
design.

I would expand on the spring tension comments. Often not only is spring =
tension weak, the metal spring is also corroded - so there is no way of =
ever getting proper pressure from it - it would have to be replaced.

The other thing is flange center friction. If it is too tight, you'll =
never get good damping.

All these things should be discussed with the piano owner prior to =
replacing dampers on a piano (especially an older vertical). First I =
evaluate damper travel and apparent spring pressure. If those seem OK, I =
then warn them that felt replacement should help, but no guarantees =
without completely rebuilding the damper system - and yes, that would be =
many, many more bucks!

And FWIW, I have done the Spurlock vertical damper redesign thing a =
number of times with excellent results. And for whatever reason, I enjoy =
making dampers - for anyone that doesn't like making their own, I am =
happy to make a set for anyone to your specifications.

Terry Farrell
  ----- Original Message -----=20
  From: Tvak@aol.com=20
  To: pianotech@ptg.org=20
  Sent: Tuesday, November 30, 2004 10:33 PM
  Subject: damper problem (probably just stupidity on my part)


  List

  I don't think anyone can help me with this, but here goes...

  I replaced the damper felts on an Acrosonic spinet.  My initial =
diagnosis and decision to replace the damper felts was based on the =
familiar sound of ringing after notes were played.  I did notice that =
the spoons were lifting most of the dampers very early, preventing some =
of the dampers from having good contact pressure with the string, but I =
found a few that were OK and when I checked them, they didn't dampen =
very well, either, so I decided that the felt (which was original to =
this 1940s piano) needed replacing.  It was my hope that the additional =
height from the new felt would remedy the spoon lift timing, but if not =
I was ready to regulate those suckers, too.

  When I put the action back in the piano I found that the dampening is =
not much better.  But why?
       1. There is follow through on all the dampers.  (In case I'm not =
clear, I mean that the damper will
            move with the string when the string is pressed toward the =
soundboard, indicating that there    =20
            is proper pressure for the damper to dampen the string.)
       2. The spoons are indeed lifting at the proper time, and so they =
are not impeding the damper levers from pressing                against =
the strings.   (There is follow through.)=20
       3. The damper pedal is not holding the dampers away from the =
strings.  (Again, there is follow=20
            through.)
       4. The dampers are seated well on the strings.  It's not a string =
level issue.  (It's not one of the
            three strings on a trichord, for instance.  It's all of them =
equally.)
       5. The dampers are aligned to the strings properly.  The bichords =
dampen both strings equally, the trichords dampen all           three =
equally.  Just not enough, it seems.

  They do all dampen somewhat.  I mean, it's not like the pedal is down. =
 But there is definitely sound after the keys are returned to the up =
position.  It sounds just about the same as it did before I replaced =
them!  (A second question might be, who among you would charge this =
woman for your work?  I won't, until I can get it to sound better.)

  I did file the hammers, which were heavily groovy, man.  I didn't =
change the hammer blow distance though, due to the spoons initially =
being on the early side, I thought it was best to just leave it as is.  =
I was happy that the spoon lift was OK with the new damper felts.  I =
hate regulating spoons.  I didn't do anything else to the piano, other =
than replace a few bridle straps.
      =20
  I'm going back on Saturday to check it out, and see if perhaps the =
felt has started to conform to the contour of the strings and dampen =
better, but if they don't, then what?  I'll try dampening all the treble =
strings that have no dampers with a towel and see if the ringing goes =
away, but I don't think it will.

  Any ideas?  Is there something I've not thought of?  Any diagnostic =
procedures that might shed light on this?

  Thanks in advance,=20

  Tom Sivak
  Chicago PTG Associate

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