Nagra PORTABLE ANALOGUE AUDIO TAPE RECORDER Instruction Manual - page 22
3.0 OPERATION
On the right-hand side of the front panel is the main function selector, which determines the mode in
which the Nagra works. By putting it into the position "Test", all the circuits are powered, but not the
is motor. If the meter switch, on the upper right-hand side of the modulometer, is switched to the
"BATT. RESERVE" position, the needle of the modulometer indicates that the Nagra is powered. (if
this is not the case see POWER SUPPLY in this manual).
With fresh batteries, the needle will not advance to more than half way up the scale. It only reaches
the extreme right of the scale with an external power supply.
After checking the power supply, put the meter switch to the "LEVEL" position (recording or
modulation level). A microphone can receive sounds of a very variable intensity. The tape must be
recorded as fully as possible, but without the high frequencies passing a level called the "saturation"
level. The modulometer indicates the level of modulation. The needle can deflect up to the mark
"Max" on the right of the scale, but should not pass this limit. If the needle is deflected less, the
recording will be of a lower level.
The sensitivity, that is to say, the level of recording for a given sound, can be controlled either
manually or automatically. The choice is made by means of the AUTOMATIC/MANUAL switch on
the upper left of the front panel. In the position "MANUAL" the level can be controlled by means of
potentiometers (6) and (7). In the position "AUTOMATIC" an Automatic Level Controller controls
the level. The modulometer deflects with respect to the incoming signal without reaching the
extreme right-hand end of the scale.
3.2 TAPE SPEED AND STANDARD SELECTION
The NAGRA 4.2 is capable of running at three different speeds, which can be selected by changing
the position of "SPEED AND EQUALIZATION" selector (20) on the top deck of the recorder
between the two spools.
The speeds available are :
3¾ ips (9.525 cm/s)
7½ ips (19.05 cm/s)
15 ips (38.10 cm/s)
Each position of this selector automatically selects the correct equalization of the machine
according to the chosen speed. There are two different positions available for each speed and they
are marked "I" and "II" which represent Standard and Low noise respectively.
For adjustments of equalization and checking of tape speed refer to the 4.2 SERVICE MANUAL.
NOTE:
The NAGRA 4.2 is only equipped with one recording bias oscillator and it is therefore only
possible to bias the recorder for one specific tape type at any one time. However, it is
possible to optimize the equalization in the second position (LN) for a different tape.
2.3 LOADING A TAPE ON THE RECORDER
Select "STOP", then release the tape path from the heads, guides and capstan shaft by pulling
lever (32) forward, until it comes to a complete stop. Remove the spool retaining nuts and place a
reel of tape on the left-hand turntable, with the loose end of the tape coming from the left-hand side
of the spool. Pass the tape around the left-hand guide roller and across in front of the heads, and
around the right-hand guide roller. Attach the end of the tape to the empty spool on the right-hand
turntable. Replace the two spool retaining nuts, and close lever (32) until it reaches its original
position, thus putting the tape into contact with the heads.