bobbling hammers-1993 Kranich&Bach

[John McKone]

Lance,

I don't about the K&B you're working on, but one thing that seems to
contribute to this problem on Yamaha's (particularly the P22) is the
relationship between let-off and damper lift.

These pianos sometimes are set up so that the let-off button and the damper
spoon are contacted simultaneously.  This produces enough friction to
create a "false bottom" to the key stroke, particularly on a soft blow.
The "false bottom" causes enough hesitation in the key to allow a bobble
before the jack can get through let-off.


John Mckone, RPT

>Dear List,
>I GIVE UP!  I've been trying to help a customer of mine who bought a cheap
>Kranich & Bach (made in Europe, 1993, sold by Baldwin) 42" upright.  This
>piano had double striking or bobbling hammers when I first saw it.  To be
>brief and to the point; I added let-off distance and dip, still some
>bobbling on soft blows, added more, still bobbling at times, then I added
>key height/dip, adjusted checking, and unless you are VERY deliberate and
>get to the very end of each key stroke, IT STILL DOES IT occasionally.
>Maker won't help, they said (basically) that's what you get for buying a
>cheap piano.  Now, the piano is no fun to play and you still get the
>occasional bobble if you're not careful.
>
>I have come across this problem hundreds of times over the years and have
>always been able to regulate it out, but I can't seem to get this one to
>stop without regulating it out of the comfort zone.  I remember some
>Samicks and Yamahas in the low tenor had this problem due to the angle of
>the surface on the butt where the jack contacts.  Any ideas?  Thanks very
>much!
>Lance Lafargue, RPT
>New Orleans Chapter
>Covington, LA.
>lafargue@iamerica.net

John McKone, RPT
St. louis Park, Minnesota
(612) 280-8375
mckonejw@skypoint.com