Yamaha Jumping Jacks

[Geoff Sykes]

Not to dis the Crescendo punching's, which I hear nothing but good reports
about, but this is not a soft blow problem, it's a slow key movement
problem. My experience with this double-strike phenomena is that the hammer
jumps off the jack about halfway through the keystroke, (in other words long
before the jack actually releases from under the butt), hits the string and
bounces back onto the jack, the keystroke continues through the point of
actual let-off where the jack actually does it's work of throwing the hammer
into the strings, and then the hammer bounces back correctly into the
backcheck. The key then completes it's stroke eventually landing onto the
front rail punching. My point of all this is that the double-strike is not
the result of a soft blow so much as it is the result of an improperly
functioning action during a slow key movement. It happens long before the
front rail punching's are even part of the picture.

-- Geoff Sykes
-- Assoc. Los Angeles



-----Original Message-----
From: pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org] On Behalf
Of Jurgen Goering
Sent: Thursday, November 03, 2005 9:37 AM
To: pianotech
Subject: Yamaha Jumping Jacks



Seeing that the double strikes are a soft-blow phenomenon, this problem 
could be alleviated by use of Crescendo front rail punchings.   
Crecendo punchings are made of a firm and resilient felt, which results 
in the same dip and aftertouch on a light blow as on a heavy blow.  You 
essentially get almost 1 mm "extra" keystroke on a soft blow as 
compared to using the standard front rail punchings.  With proper 
aftertouch and the jack escaping from the hammer butt, the hammer will 
check and not bobble.

Check out:
http://www.pianofortesupply.com/punchings.html

Jurgen Goering
Piano Forte Supply
www.pianofortesupply.com

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