Shigeru Kawai regulation

[A440A@AOL.COM]

 Kevin wrote:
 
>> There are a couple of regulation differences that are interesting.
>> #1-Drop is set slightly early, and #2- jack height to rep lever height is
>> set so that there is no winking. The distance (jack height to rep lever
>> top) is subtle, so as not to cause a hammer line wave.
>> I beleive the reasoning for the earlier than usual drop, is that there
>> is a smoother feel if drop and let-off are spaced slightly.
>> Also, I beleive their thinking is, an earlier drop allows a safety
> net  which insures a positive 'scrape' or contact by the jack, which would 
be
>> reduced if the drop timing is later that the let-off timing. In other
>> words, let the jack do it's job of lifting the hammer. Keep the spring
>> loaded rep lever out of the picture.
 
Greetings, 
   The only problem here is that the loaded rep lever is NOT out of the 
picture.  It is being compressed by the pressure of the finger on the key, 
and this compression begins at the very last bit of control the pianist may 
want to exert in the softest passages. 
   The combination of drop button contact and jack tender contact may or may 
not be exactly the same, that depends on a lot of geometry and dimensions 
being perfect.  Staggering the contact times, like we do on the ranks on a 
harpsichord, lessens the apparent effect, but is no reason to increase the 
distance of drop. 
 
   You can play a note on a grand piano very softly without the jack in 
place. The rep lever will usually carry the hammer up if there is any 
positive force from the spring.  Imagine that on the softest note the pianist 
can play, that the weight of the hammer is carried  by the rep lever. The 
friction of the jack against the knuckle is going to be virtually nil, and 
upon reaching  let-off, the only resistance to the key will be the spring 
acting against the drop button on one end, and acting against the let-off 
button on the other,(via the jack tender).  This allows the jack to be 
touching the leather, which I consider important, but on pianissimo play, the 
pianist has a very fine control, not needing to get through let-off with an 
early spring in play.    These things contribute to what I call "transparent 
escapement". 
    My personal set-up is to have the fastest spring possible without it 
being felt in the key,(any more is a waste, since it doesn't apprecialby 
increase the key return speed in fast repetition), the slightest contact 
between jack and knuckle that I can feel with my finger on the tender, and 
the let-off and drop both set at the same distance to the string.  I 
determine this distance by the requirements of the job.  On the concert stage 
and the studios, the distance is as close as possible to the maximum 
excursion of the string. In the homes, where durability is a consideration, 
slightly more.   
Regards, 
Ed Foote RPT