Yamaha bobbling

[Richard Brekne]

Hi Ron, and list

Nice points made here, and I can go a long ways down the road to 
agreeing with the issue of pressing through lettoff correctly. On both 
uprights and grands for that matter.

That said there are several things that can cause a borderline 
pianist/piano combination to uncessessarilly suffer from this bobbling 
condition that can be easily enough addressed without compromising the 
actions power and control. Several of these have already been mentioned 
and many of these easily fall into what most techs would allow for as 
<<reasonable, yet not critically PERFECT>> regulation.

Most of that is found looking at what parts are doing what at that last 
2-3 mm of keystroke, and much of the rest of it has to do with friction 
issues.  But I agree that finding real bobbling problems in Yamahas on a 
regular basis is not something I run into often.  Quite the opposite, I 
find Yamahas by and large to be one of the most problem free out of the 
box, most stable long term instruments available.

Cheers
RicB


Ron Nossaman wrote:

> I've never seen this problem in a Yamaha that's being played like a 
> piano, but I suppose it's possible. Typically, this has always been a 
> problem with these actions with beginners, kids, and folks with a very 
> tentative touch. To me, it looks like a design thing. The ratio of 
> jack length to toe (tender) length is high, so any drag of the jack at 
> the butt translates to increased resistance at the toe, which is more 
> readily felt at the key. As the key is depressed, the pianist picks up 
> resistance from the damper spring first. This isn't far into the 
> stroke, isn't out of the ordinary, and is ignored. Near the bottom of 
> the stroke, added resistance is encountered at letoff, when the jack 
> toe hits the letoff button, and they quit pushing. When they don't 
> push through the letoff resistance and finish the stroke, it makes the 
> hammer bobble because the jack is still under the butt. Assuming the 
> action is in reasonable, though not critically PERFECT regulation, the 
> 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. That gets the letoff resistance 
> farther up in the stroke where they tend to push through it instead of 
> stopping. 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, or at least it wouldn't have been a problem 
> unless they are just looking for trouble. 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 a 
> functional 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.
>
> These actions work fine, in my opinion, but just aren't the sloppy and 
> infinitely forgiving worn out old spinet or upright action they 
> typically replace, and demand some portion of the player's attention 
> to adapt to.
>
> For what it's worth, that's my take.
> Ron N
>
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