Buzzing Bass & Winding length

[John Woodrow]

I am experiencing a problem with a 20 year old Yamaha UX upright (fancy
version of a U3) that I cannot pinpoint.

There is a very pronounced buzz in the last bass note at the tenor end of
the bass bridge(Bb).  The bridge appears to be in good shape.  I have given
both strings of the unison a twist, no improvement.  I have replaced one of
the strings of the unison, still no improvement.

I have checked out a few other old U3's and there appears to be a tendency
for all of them to have a buzz to some degree in this note though not as
pronounced as this particular piano.

Also, at the hitch pin end of the new string, the brass winding is now
about 3/16" shorter than the other original string of the unison.  The
winding appears to have crept up this much from a 'crimp' mark on the
string which is at about the correct length for the winding.  'Crimp' is a
bad term as it appears to be where the inner string changes from a
hexagonal section ??? to a round section but I can't be sure (poor light
and bad eye sight, got to get glasses).    

I spoke to the string maker who reckons this is all OK, but I have my
doubts.  Reblitz reckons the windings of bass unisons should be within
1/16" in length.

Appreciate any comments on (a) what could be causing the buzz, and (b) the
different length of the windings in the unison.

Regards,
John Woodrow
Sydney, Australia 

Email:		Woodroj@syvax.email.dupont.com
Telephone:	61-2-99236103
Fax:		61-2-99236099