Pianotech

Subject: Yamaha GH1 scale

1.  Yamaha GH1 scale

Posted 12 days ago
Hi everybody,

I'm sitting at a Yamaha GH1 B from the late/mid 80s (448XXXX SN). It has the issue universal to these pianos where the notes on the bottom treble don't tonally match the rest of the instrument. They're producing an offensive "bong" sound. It's beyond what simple needles or anything dissolved in lacquer can fix. This is a scaling problem.

I seem to remember that there's a known scale adjustment that can be done here by changing out some of the bottom tenor bridge trichords for bichords (and agraffes/dampers as well). Does anyone have scaling or other info on this?

Thanks,
Nate Reyburn, RPT

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http://www.facebook.com/ReyburnPianoTech
http://www.reyburnpiano.com
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2.  RE: Yamaha GH1 scale

Posted 11 days ago
Nate,

I know Larry Buck has that kind of info.

In addition, riblets and mass loading of the bridge/soundboard can help that too. Del Fandrich is a good resource for that.

Pwg

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Peter Grey
Stratham NH
603-686-2395
pianodoctor57@gmail.com
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3.  RE: Yamaha GH1 scale

Posted 11 days ago
Edited by Jim Ialeggio 11 days ago
I've had success with rescaling the entire tenor of a GPS-1, from #26 to the capo, with Paullelo wire, using the existing bridge layout. The GPS-1 is even worse than the GH series, discontinued almost immediately, so I think you could have a chance with an appropriate rescale.

What are the Speaking lengths of those nasty notes, and what notes are they...B2, C2?

Paullelo Type 1 core, raising the BP%  and using Paullelo soft iron wraps. I would be happy to try and rescale this sucker, leaving the bridge layout alone. You would have to add a couple of hitches though...not a biggy.   ​

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Jim Ialeggio
grandpianosolutions.com
Shirley, MA
978 425-9026
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4.  RE: Yamaha GH1 scale

Posted 11 days ago
Nate-
I've had good results rescaling several foreshortened scale pianos, adding wrapped strings to the low tenor.
If you have a Windows computer, ScaleRipper is an old shareware program that is easy to use, and lets you substitute wrapped strings.
James Arledge can rescale for you, and probably has scales for GH-1.

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Ed Sutton
ed440@me.com
(980) 254-7413
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5.  RE: Yamaha GH1 scale

Posted 11 days ago
Del Fandrich and I did one of these for one of my clients a few years ago with reasonably good results. I believe we had to add at least one hitch pin to the plate. We kept the original trichord agraffs, and just used the outside holes. The trichord dampers worked fine as bichord dampers.

Del also installed a pretty hefty brass weight to the underside of the end of the bridge to help lower the volume and increase the sustain of those last couple of notes.

A key part of these types of jobs is lowering the client's explanation. Del was clear to tell the client that the problem won't be fixed, but it will be "less bad".

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Ryan Sowers
Olympia WA
360-705-4160
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6.  RE: Yamaha GH1 scale

Posted 11 days ago
Changing to Paulello Type 1 will be the least invasive and get the most bang for your buck, imo. I'd rather recommend a better piano than go through adding hitch pins, etc.

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Philip Stewart
609-774-7571
www.njpianoservice.com
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7.  RE: Yamaha GH1 scale

Posted 11 days ago
Doing it now, I would also add a short auxiliary rib.

ddf

--
Delwin D Fandrich
Fandrich Piano Company, Inc.
Piano Design and Manufacturing Consulting Services -- Worldwide
6939 Foothill Ct SW -- Olympia, WA 98512 -- USA
Phone 360.515.0119 -- Mobile 360.388.6525





8.  RE: Yamaha GH1 scale

Posted 11 days ago
Important information missing. Is this Nate's piano or a client's piano? Is the customer complaining?

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Larry Messerly, RPT
Bringing Harmony to Homes
www.lacrossepianotuning.com
ljmesserly@gmail.com
928-899-7292
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9.  RE: Yamaha GH1 scale

Posted 9 days ago
Thanks for the info. Following up on this with Alredge. If there's known drop-in strings that help dramatically, that would be a great way to go.

FWIW, this is a customer piano and there are complaints about that area of the piano.

Is there more info on the short auxilarry rib or weight addition, Del?

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http://www.facebook.com/ReyburnPianoTech
http://www.reyburnpiano.com
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10.  RE: Yamaha GH1 scale

Posted 9 days ago
A nice pair of springy wool socks, rolled up and stuffed between the soundboard and a beam or console plate, can take some of the edge off those "boinging" bottom tenor notes! Try to get them just below the end of the long bridge. Experiment with how tightly to wedge them in.

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Ed Sutton
ed440@me.com
(980) 254-7413
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11.  RE: Yamaha GH1 scale

Posted 9 days ago
Nate,

You can start with a piece of 1" - 1.5" diameter brass, about 200g or so. Drill a hole through the center and attach it to the underside of the SB directly under (and screwed into) the tail end of the low tenor bridge. If there is already a soundboard button there, all the better...take it off and use that hole. If not, just locate carefully so you go into the bridge.

See if that makes any difference (improvement). If so, make another weight at 300g or 400g and try them out. If one sounds better than another use the one that sounds best. It is largely trial and error...going too far and then backing up.

For riblets, Del's brother Darrell will sell you a set of riblets (a dozen I think). Experiment with them between the existing ribs. Its nice when you have buttons installed in between the ribs. Just take them off and substitute with a riblet. If it does nothing, or you don't like it, just take it off and put the button back on.

There is an article in the journal several years ago on this. I don't recall the issue. Someone else might though.

The general idea is that you are trying to slow down the transfer of energy to the soundboard, increasing its impedance. This tends to even things out, increase sustain, reduce explosive sounds, etc. Completely reversible until you decide to permanently attach them. It also has a tendency to be cumulative in nature. Don't expect one riblet, or one weight to produce miraculous results. Put them on, evaluate, remove, evaluate, repeat, etc. In conjunction with some judicious rescaling, probably a nice result can be had.

Pwg

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Peter Grey
Stratham NH
603-686-2395
pianodoctor57@gmail.com
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12.  RE: Yamaha GH1 scale

Posted 9 days ago
Have you read the articles I wrote for the Journal on this subject? They will give you a basic understanding of the problem.

There are no "one-size-fits-all" answers here.

Del

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[Delwin D] Fandrich] [RPT]
[Piano Design & Manufacturing Consultant]
[Fandrich Piano Co., Inc.]
[Olympia] [WA]
[360-515-0119]
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