Petrof Quality

[David Ilvedson]

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I've got a similar Petrof, but smaller...5' 7" or so...same problem.   =
It does seem, to me you're going to have a really low upweight...?   Wh=
y not, as Dean wrote, remove weight from the hammer?

David Ilvedson, RPT
Pacifica, California




Original message
From: Erwinspiano@aol.com
To: pianotech@ptg.org
Received: 12/8/2005 10:40:48 AM
Subject: Petrof Quality


  Listers
   After a recent encounter with a 10 year old 6 ft. Petrof ,my once fa=
irly high opinion of them has sunk. I generally have liked the sound of=
 there bellies & the workamnship looked good but  I had the following e=
xperience.
  The action although upon examination had a nicely done 5.3 overall ac=
tion ration the touch was extremely heavy high 60's down & below 20 up.=
 The problem is that the hammers were just way to heavy for example Not=
e 16 was 10.5 grams. That's  hammer wt. not strike weight.
  So extrapolate those heavier than normal readings thru the rest of th=
e  scale.
  Since the desired service was to make it play more like a Saturn than=
 a truck  & no parts were being changed the original parts were used. T=
he remdey was to  add one lead to a sparsely leaded keyboard  & then ad=
just the wippen springs. Even at that the average down up weight was ar=
ound 56 to 22 up which is a 39 balance weight.
 I believe  the real solution was a lighter set of hammers & subsequent=
 even leading applied with springs detached to some higher than normal =
nominal number down/up numbers & then re -tweaking the springs. for a l=
ight bit of wippen weight removal from the system.
  This to me was a prime example of a nicely done leverage set up that =
was doomed from the git go due to extreme hammer weights It seems  all =
grand piano actions fall within certain reasonable & typical leverages =
that when exceeded are problematic until rectified by appropriate count=
er measures.

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