[AV Media Matters] Spring Wound Tape Recorder

[m.biel@morehead-st.edu]

A friend of mine in Ljubljana, Slovenia is looking for information
about a tape recorder which was used by his ethnomusicalogical
archive in the 1950s.  They would really like a schematic and a copy
of the instruction manual. It is the Magnemite Portable, model
610-C, made by the Amplifier Corp. of America, New York,  serial
number: 3703

 It is an unusual machine in that it is spring wound.  I remember
seeing it in the annual tape recorder directories that AudioDevices
published in the early 60s, but have no other print info.  The
archive received it from a group of Slovenian expats in the US
around 1956.  It is about the size of a Nagra, uses 7-inch reels of
quarter inch tape, the electronics runs only off of 4.5 volt and 90
volt battery power, and the motor is spring wound.  The main visual
feature of the machine as pictured in the recorder guide is a large
spoked-wheel on top which I had always thought was the spring
winding mechanism.  It actually is a removable flywheel for the
capstan.  Erasure is done by a rotatable permanent magnet--you had
better remember to rotate it away from the tape path when not
recording!!!

We had a chance to inspect and operate the mechanics of the machine
a few months ago in Slovenia.  The machine threads backwards
compared to most machines.  To allow the tape to be played on any
standard half-track machine, the lower half of the tape is recorded
because the tape runs from the right to left reels from the outside
back towards the outside back.  Thus the reels and the capstan all
rotate clockwise.  Think about it folks, why would a tape recorder
have these things rotating clockwise???  It is because the motor is
a PHONOGRAPH motor!!  We didn't have a strobe disc handy, but it
seemed to me that the capstan was rotating at 78!  We located a
screwdriver speed adjustment on the flying-ball governor--but didn't
touch it, of course.  We are curious if the instruction manual had
you adjust the speed with a phonograph strobe disc.  If so, consider
the fact that in 60 cycle territory--where the machine was built--78
is actually 78.26, but in 50 cycle territory the speed is 77.91.
Using a strobe disc in Europe would result in too slow a tape
speed.

If any of you have any data on this machine--or have one--let me
know.

Mike Biel  m.biel@morehead-st.edu