[pianotech] Bobbling hammers and jack spring pressure?

Ryan Sowers tunerryan at gmail.com
Thu Jan 22 15:49:11 PST 2009


My vote is for the damper springs. They are often set much stronger than
they need to be and do cause some resistance to a full key stroke during
gentile playing. I ran into a similar problem a while back and a compromise
between a little extra let-off, a tiny bit more key-dip, a weaker damper
spring, and timing just a wee bit later. Sometimes you can combine several
subtle adjustments to get the result your looking for. Ultimately I believe
this may be a geometry issue that these pianos might have. I was recently
having a conversation with Ed McMorrow about this and he claimed it had
something to do with the relations of the action centers and over centering
of the hammer. We hear so much about grand action geometry but not enough
about upright geometry.

On Wed, Jan 21, 2009 at 8:22 AM, Gregor _ <karlkaputt at hotmail.com> wrote:

>  List,
>
> is there a way to ease the jack spring? I have problems with a Yamaha P121N
> upright that has bobbling hammers. The hammer butt is dancing on the jack
> tip. All regulation measures are okay and there is enough aftertouch. I
> suspect the jack spring being too strong. Any thoughts how to get it right?
>
> There is no lost motion, check is about 15 mm, aftertouch is okay and I
> gave some talkum powder to the jack tip and the let off button. The only
> thing that helped was to set the let off to 10 mm, but that´s not a
> satisfying solution. The strange thing is that one could play without
> bobbling hammers but something makes the player stop pressing down the key
> before the let off point. A very subtile resistance gives the player a hint
> that the key is pressed down now, but that´s not right. The player could and
> should press further on. The strange thing is that this problem is new for a
> few days. I should mention that we had very dry air last weeks and the
> customer has a floor heating. Therefore I suspect a connection between this
> problem and the dry air.
>
> Any comments?
>
> Gregor
>
> ------------------------------
> What can you do with the new Windows Live? Find out<http://www.microsoft.com/windows/windowslive/default.aspx>
>



-- 
Ryan Sowers, RPT
Puget Sound Chapter
Olympia, WA
www.pianova.net
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://ptg.org/pipermail/pianotech_ptg.org/attachments/20090122/988b23a2/attachment.html>


More information about the pianotech mailing list

This PTG archive page provided courtesy of Moy Piano Service, LLC