Good day.

I was at my friend's house playing his Petrof grand. I hold 2 or more keys down with the sustain pedal on. As soon as I release the sustain pedal I feel bump on the keys. Some keys are very noticeable and some not.
The next day, I visited a piano shop and I get the same feeling too the new pianos. Again some are very noticeable and some not. Is it normal?

Regards

Sounds like the damper upstop rail is too high.

Or maybe the pedal is lifting the dampers higher than the keys do? In any case, it's a matter of regulation of the piano: how well the dealer has prepared the piano for sale.

On a grand, for example, press the sustain pedal with small, rapid movements, gradually pressing down further. Watch the dampers to see if any individuals move before the rest. The entire set of dampers should move as a single unit. This is a matter of adjustment (regulation).

--Cy--

And the damper tray is lifting the damper underlevers too high. (cy beat me too it)

What you're feeling is the weight of the underlevers dropping back onto the keys. As Cy suggests, the keys should lift the dampers a very small amount higher than the pedals do to avoid this very thing.

There's usually a capstan or screw that regulates how high the pedal can lift the dampers. It's located on the bottom of the piano body, just above the lever that the pedal rod pushes up on when the pedal is depressed. On some pianos, buckskin or hard felt needs to be added because there is no adjusting screw.

Thank you for the replies.

Yesterday, the technician came and he adjusted the pedal rod nut. He also removed the action and adjusted the "stopper". I cannot remember the actual term. He said that the felt near the "stopper" have compressed due to playing and maybe too much of pedaling. The dampers are actually going up to high. And, when the pedal is released the dampers drop and you'll feel the bump.

I thought the job will take sometime but only 10 minutes.

Jay,

I'm not there, so I can't tell what he did, but I don't think he should have had to remove the action to adjust what needed adjusting. I hope he didn't use the upstop rail as a damper travel limiter, because that isn't its purpose.

The upstop rail limits the amount the dampers travel during play, but it is there to keep the dampers from bouncing while playing the keys, not to keep the dampers from rising too high when the pedal is depressed. There should be clearance between the damper underlevers and the upstop rail when the pedal is depressed.

As I stated in my last post, the adjustment for limiting pedal travel is on the underside of the body of the piano.

EZ sustain pedal adjustment while-u-wait!

1). Adjust rod so there is a small amount--1/8 inch or so--of play before it begins to lift the dampers (I push the pedal with my hand, because it's easier to feel the beginning of the lift)

2). Adjust upstop rail so that there is 1/8 inch +/- of play above the damper when the key is depressed (lift damper by hand to check for play)

3). Adjust pedal stop nut/capstan/felt/whatever so that the pedal lifts the dampers to the same level or very slightly less than the white keys lift their dampers. The black keys should lift their dampers a little higher.

Hope this helps, even if it is after da fact!

Thank you Dave.

The technician did lift the damper with his hand. He said that the play is too great and it is suppose to be no more than ~1.5mm. That could be the reason why he removed the action and adjusted upstop rail. After your explanation, I think the technician did 2 jobs instead of 1.

Regards.

I would assume he adjusted the upstop rail. I've seen a lot of Petrofs where they sometimes get knocked up a bit during transit. Don't ask me how, but they do.