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<DIV><FONT size=2 face=Arial>Thank you again Larry, much appreciated. Please
pass on my thanks to your brother too.</FONT></DIV>
<DIV><FONT size=2 face=Arial>Just for interest, we will be in the States in
June. I will celebrating my 70th in New York, and hope to catch up with Judy
Carmichael who I tuned for whilst she was over here the Wangaratta Jazz festival
a few years ago. We still keep in touch, she is a great lady and
terrific stride or scat player.</FONT></DIV>
<DIV><FONT size=2 face=Arial>best regards,</FONT></DIV>
<DIV><FONT size=2 face=Arial>David Lawson</FONT></DIV>
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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="FONT: 10pt arial; BACKGROUND: #e4e4e4; font-color: black"><B>From:</B>
<A title=larryf@pacifier.com href="mailto:larryf@pacifier.com">Larry Fisher
RPT</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=pianotech@ptg.org
href="mailto:pianotech@ptg.org">pianotech</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Wednesday, March 02, 2011 1:06
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> [pianotech] unusual tuning
fork</DIV>
<DIV><BR></DIV>
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<DIV style="FONT-FAMILY: 'Calibri'; COLOR: #000000; FONT-SIZE: 12pt">
<DIV>Here’s the response from my brother. </DIV>
<DIV> </DIV>
<DIV>*************</DIV>
<DIV> </DIV>
<DIV>Frequency standards for frequencies way above audio range were made of
</DIV>
<DIV>crystalline materials more than 60 years ago. They certainly
wouldn't be </DIV>
<DIV>made of metal prongs. The accuracy would be very low in that
range.</DIV>
<DIV> </DIV>
<DIV>This device looks like it was for audio purposes, and since it is shaped
</DIV>
<DIV>like a tuning fork, it was probably used for a reference of some
sort. The </DIV>
<DIV>coil is either there for picking up the vibration - like an electric
guitar </DIV>
<DIV>pickup - or for exciting the fork just enough to keep it humming.</DIV>
<DIV> </DIV>
<DIV>Tom</DIV>
<DIV> </DIV>
<DIV>***************</DIV>
<DIV> </DIV>
<DIV>Keeping it in oscillation is something I hadn’t considered.</DIV>
<DIV> </DIV>
<DIV>100 cps would be higher in frequency than AC hum. (60 cps) G11 is
quite low. The tines are quite thin compared to what we use to tune
pianos with. It would take less energy to keep a thin tined fork in
oscillation than a thicker tined fork. The 3 VDC power supplied would be
to activate the coil as opposed to sensing the coil as in a guitar pick up
which typically is a much lower voltage. A vibrating tine crossing
through the magnetic flux would generate a voltage that would then act as a
pick up. I’m going to put my vote on a small voltage to keep the tines
moving. The extra hardware at the ends of the tines has me
puzzled.</DIV>
<DIV> </DIV>
<DIV>That was fun.</DIV>
<DIV> </DIV>
<DIV>Lar</DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV> </DIV>
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