Aftertouch (was Young Chang)

[Z! Reinhardt]

Hi Mike --

Let's see ... where to start ....

Assuming that glider studs, keyheight, keydip, hammerline, repetition lever
height, springs, and jack position to knuckle all check out OK ........

Remove the action and put it on a firm flat surface.  Take a reading of the
distance between the keybed and the undersides of the strings (string
height) at the ends of each section.  Now measure the highest point of the
hammer's travel from the work surface to the tip of the hammer.  This could
well be higher than space permits in the action cavity in your case.

Now rough-set drop to be about a quarter-inch (maybe a little more) below
the measured string height.  Next, set let-off to occur somewhere above
drop but below the string height.  Put the action back in the piano, refine
let-off (I'm one of those technicians who prefers to do the fussy stuff
with the action in place rather than out on a bench).  Pull the action back
out to refine drop.  Check your work with the action in place by a) playing
each key softly and feeling for consistency in and depth of aftertouch, and
b) stepping on the sustain pedal (to get the dampers out of the way) and
playing each key very slowly to the point of let-off.  This should be a
good solid 'point of resistance' rather than a 'hardening of mush.'  This
is caused by the jack tail touching the let-off button, the repetition
lever contacting the drop screw and the top of the jack being in contact
with the knuckle.  The more synchronized these 3 contacts, the more solid
the 'point of resistance.' 

It's this very business of synchronizing the 3 contacts and having let-off
occur where it is supposed to that I call the Aftertouch Equation because
of the variables involved.

For a better, more thorough discussion of Aftertouch, check out Yamaha's
offerings.  If you go to PTG regionals or National Convention,  you can
attend some great classes on the subject and get some of the best printed
handouts anywhere.

ZR!  RPT
Ann Arbor  MI
diskladame@provide.net

----------
> From: Mike Masters <agraffes@worldnet.att.net>
> To: pianotech@ptg.org
> Subject: Young Chang Aftertouch
> Date: Wednesday, May 13, 1998 4:22 PM
> 
> List,
> I have a regulation problem/questions regarding a 6 year old Young Chang 
> G-157. Apparently a salesman from the dealer has put himself across as a 
> technician for the last 6 years and has been tooning the piano since it 
> was purchased. Has been having problems with "sticky keys" since day 1. 
> The customer called the dealer and was referred to me.
> 
> I can see where the problem lies but am not quite sure what the cause 
> (or than manufacturer mishap) or what may be the best way to properly 
> regulate. The problem has to do with insufficient aftertouch. Hammers 
> have no let-off, drop, or checking for that matter unless a sharp 
> blow(test-blow strength) is used. I think this is explained as the felt 
> punchings are compressing enough on the hard blows to allow let-off and 
> drop to occur. Hammers are blocking against the strings on soft blows no 
> feel of let-off or drop or aftertouch in keystroke. 
> 
> Key height is good, key dip is sufficient (as far as factory specs and 
> geometry go) blow distance is about 47 mm(which is good) let off is 
> high, no drop, unless front rail punchings are removed which seems to 
> (in reference to sharp dip) be too much. I don't want to increase the 
> dip by as much as the action is asking for because the sharps will be at 
> the same height as the naturals when depressed.
> 
> Now my questions are what is the best approach to proper regulation?
> Would decreasing the blow distance to allow more aftertouch be wise or 
> would increasing the key dip be better. Any suggestions or comments are 
> appreciated.
> Thanks in advance.
> 
> Mike Masters
> Masters Piano Service
> Lakewood, OH