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2. OPERATION
It
is essential, however, that the instruction manual of each instrument be
read carefully before using the equipment.
1) Place the record player on a vibration free table. Connect and set the
apparatus as shown in Fig. 2.1. Select the desired recording characteristic*)
Pick-up
under test
Cont.
ecord.
0
0
fig.
2.1.
Set-up for automatic frequency response plotting with a QR
2001
record.
When using a QR
2006
or
2009
the adjustments are the same with
~xception
of the settings of the Level Recorder, which then should be a ...
fhown
on Fig.
2.2.
A single lead is recommended between Amplifier ana
Recorder since the ground connection is already made by the synchro-starte1
connection.
by means of the 4409's FILTER SWITCH. The paper drive controls of the
2305 are set to "on", "start", "forward".
2) Preliminary Adjustments. It is convenient, in order to ensure that the correct
automatic stop position is attained, to play a record band before actual
measurements are taken. In addition it will be possible, during this preparatory
playing, to adjust the sensitivity of the measuring instruments. Proceed as
follows:
a) Place the pick-up on a lead-in groove for playing the selected band.
b) If the automatic synchro-starter does not operate after a few seconds
playing, check that the speed of rotation is 45 r.p.m. and switch METER
RANGE on the 2603 to 10 m V. Also check that the pick-up under test
is in normal condition.
*)The
recording characteristic should be selected in order to obtain a constant reference
level.. With
amplitude
sensitive pick-ups such as piezoelectric devices or other types
with built in equalizers, the positions "IEC Curve 2 or Curve
3"
should be used. (The
IEC specifies Curve 3 for stereophonic recordings). With velocity sensitive pick-ups such
as
electrodynamic devices, the position "Lin." which gives constant recorded velocity
conditions should be used.
18
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