Replacing plain wire

[Delwin D Fandrich]

----- Original Message -----
From: "David M. Porritt" <dm.porritt@verizon.net>
To: <caut@ptg.org>
Sent: November 12, 2001 7:19 AM
Subject: Re: Replacing plain wire


>
> I was meaning the lowest plain wire section - F3 - A3 or so.  That
> area of the 243HP is improved over the 243, but still sounds like too
> low a tension.  Do you have tension figures off hand?
>
> dave
> *********** REPLY SEPARATOR  ***********

Yes. Tensions for the first octave are:
F-33 = 158 lbs (72 kgf)
F#-34 = 167 lbs (76 kgf)
G-35 = 174 lbs (79 kgf)
G#-36 = 183 lbs (83 kgf)
A-37 = 174 lbs (79 kgf)
A#-38 = 182 lbs (83 kgf)
B-39 = 189 lbs (86 kgf)
C-40 = 197 lbs (89 kgf)
C#-41 = 186 lbs (84 kgf)
D-42 = 193 lbs (88 kgf)
D#-43 = 199 lbs (90 kgf)
E-44 = 206 lbs (94 kgf)
F-45 = 194 lbs (88 kgf)
(Your results may vary depending on actual bridge placement. This tended to
vary just a bit.)

That whole redesign was a compromise--as are most redesigns of existing
pianos. The piano really needed a new plate, changing the scale from a 28
bass to a 32 bass section. Lacking that it could really use a transition
bridge for the lowest four notes in the tenor section (C#-29 through E-32),
a longer F-33 and a shorter mid-tenor. This, however, would have involved
rather more extensive changes to the plate pattern than the company was
willing to consider at the time. And there was no interest at all in a whole
new plate. As it is, tensions are extremely high from about C40 through
F#-58 (several are comfortably above 200 lbs (91 kgf) but drop off rather
rapidly below that. As I recall the total scale tension was around 43,500
lbs (19,750 kgf)--rather high for a piano of this size. About all I can say
is that it is less erratic than its processor and I'd love to do a new scale
and a new plate for a piano of this size. Or, at the least, move the V-bar
around to correct for the erratic hammer strike point and make another tenor
bridge for the piano--including a separate transition bridge for the lowest
four notes in the tenor section--and a new bass scale. Ah, well....

I'm not sure what I'd recommend to improve the tone in the area that bothers
you. It's a bit high up in the scale for wrapped strings. As it is F-33 is
only 812 mm long but, as you can see, the tension is up around 158 lbs (72
kgf) and it took a #21 wire to get it there. I don't think I'd want to see
anything any thicker.

I do have a new tenor/bass string scale for this piano (leaving the bridges
alone) that actually lowers tensions and smoothes things out a bit more, but
the lowest tri-chords remain the same.

An aside, you might check string bearing--this was often a somewhat flexible
parameter on these pianos and can cause real problems down there--especially
if it is too high.

Regards,

Del