[pianotech] Interesting action on Yamaha YUA

[Tom Driscoll]

  ----- Original Message ----- 
  From: Ken & Pat Gerler 
  To: Ed Sutton ; pianotech at ptg.org 
  Sent: Tuesday, July 07, 2009 9:19 AM
  Subject: Re: [pianotech] Interesting action on Yamaha YUA


  I watched the video clip on youtube and it looks like the hammer is acting like there is a repetition lever action of a grand in the operation. Did/does the hammer spring pull the hammer forward?

  Ken Gerler
    Ken,
    I think what is happening is that the butt loses contact with the spring before the jack fully returns. The Rep lever like movement of the hammer is from the jack sliding back under the butt.Since there is no " Push" back to the hammer when it leaves the spring  the returning jack moves  the butt-hammer assembly forward.
    Back in the 70's @ convention Steve Jellen demonstrated this on a conventional vertical action with a strong jack spring and a very weak hammer return spring. The jack overpowers the returning butt assembly and the hammer moves toward the string as the key is returning to rest.Anyway I think that is what's going on . 
    Best wishes,
    Tom Driscoll
     
        
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