Nagra 4.2 - Speed Varier Use in Filming Playback; Pilot Playback (With QSLI)

This can be done as follows:
Method A
1. Play back the tape to be transferred without slaving. When using the QSLI internal synchronizer,
put the Nagra into PLAYBACK without loudspeaker.
2. Adjust the speed with the aid of the speed varier QSV–2 in such a manner that the playback
pilot signal and the mains are approximately synchronized. The needle of the Nagra meter
(switch on "SYNC") will not swing.
3. Rewind the tape and make the transfer in the usual manner. Under these conditions, the speed cor-
rection achieved by the synchronizer will be very small.
Method B
Make the transfer in the classic manner and adjust the speed varier so that the needle (in the posi-
tion "SYNC") remains at the centre of the scale (QSLI). This method is less precise but, it is sufficient
in practice. It should be noted, however, that the interruptions of the pilot signal happen at the begin-
ning of a sequence, and it is almost always necessary to make a trial playback, adjust the speed,
rewind and then make the transfer.
Use of Speed Varier While Filming on Playback
While filming on playback, it is possible that the camera may run at an incorrect speed. It will therefore be nec-
essary to adjust the camera, if possible, to avoid any change in the tone of the final sound. If this is not possi-
ble, correction can be made with the speed varier (see above).
Recording of Facsimile and Similar Signals
A Nagra equipped with a Quartz Crystal Pilot Generator and a QSLI Synchronizer can reproduce, on playback,
frequencies with a precision of the order of 0.001%, as any slipping or stretching of the tape is automatically
compensated for. This applies to average frequencies for, inevitably, mechanical tolerances and longitudinal
vibrations of the tape will affect the instantaneous speed (wow and flutter).
Experience has shown that this precision is more than sufficient for the recording and reproduction of facsimile
signals. Other telemetering applications are, of course possible.
Pilot Playback Using a Nagra 4.2 L not Equipped with QSLI Synchronizer
Output impedance: 47kΩ ± 20%
Load impedance: from zero to infinity
Output voltage from tape recorded on Nagra 4.2 L: 330 mV ± 3 dB
Pilot Playback Made by Nagra 4.2 L Fitted with QSLI Synchronizer
Output impedance: 10 kΩ ± 20%
Load impedance: from zero to infinity
Output voltage from tape recorded on Nagra 4.2 L: 0.85 V nominal ±3 dB.
The Nagra 4.2 fitted with a QSLI can be used to measure the playback pilot signal. 0.85 V corresponds to a
meter deflection of 1 V on the scale calibrated from 0 to 2 V and normally used to measure the voltage per cell
of the batteries 1.7 V corresponds to full scale deflection.