Re: [AV Media Matters] headswitch

[Jim Wheeler <Jimwheeler@aol.com>]

Heather

Quad has four heads with only two inches of tape from one head to the
next.  
Type C has one head with 16 inches between the switch from one track to
the 
next.  If the machine has a servo that maintains the proper tape
tension, 
then the switching error will not be very large.  

I invented the first tape tension servo in 1963.  In those days, we did
not 
have time base correctors that would compensate for the tension changes
and 
eliminate the hooking at the top of the screen.

Today, VHS machines have a simple tape tension servo and some even have
a 
time base corrector built in.

If a recording is made in an extremely cold or hot environment and then 
played back at room temperature, the tape tension servo may not be able
to 
fully correct the error.

The diameter of the scanner is critical so that a tape made on one
machine 
can be played on other machines without a large switching error.  If the

machine manufacturer does not maintain rigid tolerances during
machining, 
tapes made on that machine will not interchange properly on other
machines.

There are other factors but you get the idea.

Jim Wheeler

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