Yamaha U1 regulation problem

[Ron Nossaman]

>             I know bobbling hammers can be a problem on Yamaha verticals 
> and I ve worked on hundreds of these, but I can t shorten blow any more 
> and as I mentioned, keydip-aftertouch are correct. I m hesitant to 
> increase lettoff back to its original excessive amount, so esteemed 
> colleagues ---Any suggestions? I m going back next week.

This has always been a problem with these actions with beginners, kids, and 
folks with a tentative touch. To me, it seems to be a design thing. The 
ratio of jack length to tail length is high, so any drag of the jack at the 
but translates to increased resistance at the tail. As the key is 
depressed, the pianist picks up resistance from the damper spring first, 
then hits added resistance at letoff. They just don't push through the 
letoff and finish the stroke, which makes the hammers bobble. Bottom line 
is that the person playing the piano needs to learn how to work it and the 
"problem" goes away. Since that isn't likely to happen immediately, I find 
the quickest and most easily reversible cheap trick is to bend the letoff 
rail brackets down a tad to make that letoff about 1/4" - maybe more. There 
will be a point where even the most relentless and determined soft paw 
won't be able to make the hammers bobble. That's where to leave it. Feels 
funny? No power, no control? No sweat. If they were capable of power and 
control, the problem wouldn't have come up in the first place. Next year, 
when they've learned to work the piano and complain about the lack of power 
and control (or not), these same brackets can be bent back up to get the 
letoff close enough to even it out quickly without having had to crank all 
the buttons down, then up again. Sure, I hate to compromise the action to 
accommodate someone's inability to work it, but they aren't going to change 
until (and if) they change, so all that's left is minimizing the damage 
until, and if, they do.

That's my take.

Ron N