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<DIV>Hi Larry:</DIV>
<DIV> </DIV>
<DIV>Interesting indeed! I'm also surprised that the normal vacuum is 35
instead of 40. Somewhere, I have a SMPTE standard for the quad format, and
I thought the 40 inches of H2O vacuum value was in that but maybe it's
just the geometry of the guide. I'll see if I can find it. </DIV>
<DIV> </DIV>
<DIV>I've often thought of compiling a list of differences in the way that RCA
and Ampex machines were designed. Now I know of more than I did! I
can remember some spirited debates back "in the day" over the virtues of one
machine or another. I always thought that both RCA and Ampex had their
strong and weak points, and taking the best of both would have made an
interesting machine. To some extent, that's what happened in the later
models.</DIV>
<DIV> </DIV>
<DIV>Don Norwood<BR>Digitrak Communications, Inc.<BR><A
href="http://www.digitrakcom.com">www.digitrakcom.com</A> </DIV>
<DIV> </DIV>
<DIV>----- Original Message ----- </DIV>
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<DIV
style="FONT: 10pt arial; BACKGROUND: #e4e4e4; font-color: black"><B>From:</B>
<A title=leodham@centurylink.net href="mailto:leodham@centurylink.net">L.E.
Odham</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A
title=quadlist@quadvideotapegroup.com
href="mailto:quadlist@quadvideotapegroup.com">Quad List</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Saturday, June 02, 2012 1:52
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [QuadList] Ampex Quad VTR
Airflow Requirements</DIV>
<DIV><BR></DIV>
<DIV
style="FONT-FAMILY: verdana,helvetica,sans-serif; COLOR: #000000; FONT-SIZE: 12pt">
<P>Hello Don,</P>
<P> </P>
<P>Attached is a manual page from a RCA TR-60 describing the vacuum
arrangement.</P>
<P>When the machine is in standby or winding the gauge reads 100 in/h2o and
when in play or rec modes it drops to 35in.(Ibelieve I said 40, but it is
actually 35in.)</P>
<P>I dont know when RCA instituted this vacuum switching arrangement or how
many models it was on, but it is on the 60 here, and it was on a 61 at
work years ago. </P>
<P>I will look around thru some more RCA manuals here. You have gotten my
curiousity up a little now as well.</P>
<P> </P>
<P>Larry</P>
<P> </P>
<P>LE Odham</P>
<P>Engr/Tech</P>
<P>TAMIS Archive</P>
<P>Knoxville,Tenn.<BR><BR></P>
<P>
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