This player, dating back to 1991, is very much a "work in progress", so much so,
in fact, that it is the first thing Jean-Marc Fontaine points out about
it - before going on about all that is wrong with it. However, it is
an interesting piece of engineering and has a few unusual features.
The arm is a radial Revox arm intended for LPs. It is maneuvered by
the three black buttons at the top of the player. Its range of travel
is a bit short for cylinders, as they don't always stop in the same
position on the mandrel. On this player, this difficulty is overcome
by moving the whole arm assembly along the cylinder axis when needed.
The arm can be easily raised and lowered by simply turning the large
knob on the back of the player in order to take cylinders of diferent
diameters. The smaller knob beside it is for fixing the arm. A special
is a possibility to swivel the arm, raising one end and lowering the
other, using the knob on the right-hand side of the arm assembly. This device is intended for use on cylinders that have a sloping surface or vary in thickness along the stylus path. Adjustments can be made while the cylinder is playing.
The pickup used is a Stanton 500, with styli of 188µ (7.4 mil),
107 µ (4,2 mil) and 94 µ (3,7 mil). Stylus pressure is normally
kept at about 3 grams.
The mandrels are made of PVC and are suspended at both ends. Once
the cylinder is in place on the mandrel, it is held by holes in its
ends, into which knobs are pushed by turning the large knob on the left-hand
side of the mandrel axle. The pressure exerted on the bearings when
tightening the mandrel is a problem, as they are not made to sustain
axial pressure.
The power supply for arm and drive motors are separate, and placed
in two boxes. Drive motor speed can be slightly adjusted and is monitored
by a stroboscope on the right-hand end of the mandrel axle.
The drive belt with its extra pulley for stretching the belt has turned
out to be rather noisy, and Jean-Marc Fontaine would also like to place
the motor somwhere else to avoid noise reaching the pickup. As for now,
the motor is rigidly bolted under the base plate.
This prototype player was developed in cooperation with the Bibliothèque
nationale de France (the French national library).
Both he and the player can be found at LAM (Laboratoire d'Acoustique
Musicale) in Paris, an institution doing research in acoustics in a
variety of ways: musical instruments, vibrations, concert hall acoustics,
the sound environment and the ageing of sound carriers among other things.
Christer Hamp, 2001
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