[pianotech] Yamaha GH1 tenor instability

[Will Truitt]

Hi Debra:

 

As a followup to Marcel's point, I would start by removing the action.  Then
take a large hand mirror and a strong light and examine the fit between the
plate flange and the pinblock for gaps visually.  You can also take a feeler
gauge of about .004 and insert it into any gap you find there and run it
along between the plate flange and pinblock until you hit resistance.  Chalk
the beginning and end points on the pinblock.  Do this along the length of
the pinblock face, and you will then have an idea of how much contact you
actually have.  Another clue is to look at the tuning pins.  If you see gaps
at the back of the tuning pin (toward the stretcher) and the pins look like
they are pressing forward against the plate bushings, that is another sign
of poor fitting.  

 

I have made tapered hardwood shims and tapped them between the plate flange
and the pinblock with glue, after lowering tension.  Upon retuning, I find
this helps stabilize the offending instruments.

 

All that being said, Ron Nossaman's and others remarks on the poor scaling
in the tenor area are right on the money.  Scalewise, it's a barking dog in
that area.

 

Will Truitt

 

From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Marcel Carey
Sent: Sunday, November 16, 2008 6:38 AM
To: Pianotech List
Subject: Re: [pianotech] Yamaha GH1 tenor instability

 

Hi Debra,
I would check the pinblock fitting. Start by tightening all pinblock screws
and then check the fitting. I've seen a couple that were rocking. I would
tune the treble and all would be fine, I would tune the bass and the treble
would go... Is that the case here? I know it does not have a very good scale
in the tenor and LOTS of compromises have to be made to make it sound just
OK, but if there is change after you tune the bass or the tenor, have a look
at the block fitting to the plate's flange. It could improve stability.
These pianos are also very sensitive to humidity changes in the lower tenor
due to low tension on the last tenor unisons.


Marcel Carey
Sherbrooke, QC

> Date: Sat, 15 Nov 2008 20:32:01 -0800
> From: debra at ladytuner.com
> To: pianotech at ptg.org
> Subject: [pianotech] Yamaha GH1 tenor instability
> 
> Has anyone else been as frustrated as I am trying to keep the tenor
> octave of the Yamaha GH1 in tune? Even if I pitch raise and
> over-pull, by the end of the tuning, that section WILL NOT HOLD! The
> tuning pins are not loose in the block but I'm still thinking that my
> next step might be to tap the tuning pins down into the pin block
> along with tapping the strings down at their bearing points. Any
> suggestions? Is this a structural problem with this model??
> 
> 
> -- 
> Debra Feiger, RPT
> 

  _____  

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