Nagra 4.2 Portable Analogue Audio Instructions Manual

							 On the other hand, for a transmission, which is wholly musical, the range of the 
transmitter tends not to be used to its full advantage with a VU meter. 
 
b) The VU meter has a scale, which is not logarithmic. For the needle to move, it is 
necessary that the level exceed -20 dB. This causes the operator to compress greater 
than is necessary, that is to increase the level of the pianissimo. This reduces the 
quality of a musical transmission while increasing the range. On the other hand, it is 
favorable if the listener is in a noisy ambience, such a car or a cinema hall. 
 
CONCLUSIONS 
 
The problem to be resolved is to know if the Nagra should be fitted with a modulometer or a VU 
meter. The modulometer allows the use of the full dynamic range of the recorder whether for noise, 
speech or music. The balance of the sound can, in any case, be achieved during the transfer. 
If a mixed transmission of words and music should be recorded on the Nagra and transmitted as 
recorded, the operator can simply modulate the speech to +2 dB or even +4 dB, and the limiter 
takes charge of any peaks, and the music to 0 or even -2dB. 
The VU meter is only justified for radio corporations where it is standardized because of operational 
habit. 
 
REMARKS ON THE CALIBRATION 
 
The term nominal recording level is that which is considered as the maximum level by habit. The 
word nominal has been used and not maximum as, in the case of the Nagra 4.2, this level can 
be exceeded by 4 dB due to a special recording process. 
 
The indication of 0 dB on the modulometer corresponds to the nominal level. It is not measurable 
with a VU meter for the needle will exceed full scale deflection, the sensitivity of the VU meter 
having been increased by 10 dB to compensate for the slowness of its response. 
Thus a signal of -10 dB, that is 10 dB below nominal level, produces on a VU meter an indication of 
0 VU whereas on the modulometer an indication of -10 dB is obtained. The calibration generator of 
the Nagra 4.2 gives a signal of about -10 dB. This corresponds to 0 VU on a VU meter. 
  
						

							 
9.0 SPECIFICATIONS 
 
DIMENSIONS AND WEIGHT 
 
Dimensions of the case with the lid closed, without knobs, feet, carrying handle, or carrying handle 
mountings: 
 
 L X W X H  
 
 12.6 x 8.8 x 4.4  
 (320 x 223 x 111 mm) 
 
Overall dimensions without handle  
 
 L X W X H  
 
 13.2 x 9.6 x 4.5  
 (335 x 243 x 114 mm) 
 
Weight, without batteries or tape 13 lb (5.89 kg) 
 
Weight with ordinary batteries, 5 reels of tape 15lb (6.8 kg)  
 
POWER  SUPPLY 
 
(Supply voltage, positive ground) –10.5 to -30 V DC. 
from –10.5 to -12 V some performances are slightly reduced 
 
Current consumption 
 
 in Test    95 mA 
 in Line Playback  180 mA 
 in Loudspeaker Playback, average level  250 mA 
 in Record  240 mA 
 in Fast Rewind  280 mA 
 
Type of batteries used (12 cells) 
 
 CEI standard R 20 
 ASA standard D and L 90 
 
Approximate length of battery life if used 2 hours every 24 hours 
 
 Eveready 950 batteries   18 hours 
 Eveready E95 batteries   32 hours 
 
Continuous use with Eveready 950 batteries 8 ½ hours 
Recording time at 7½ ips (19 cm/s) with 35µm tape 45 min. 
 
Maximum reel diameter with lid closed 5 (127 mm) 
Recording time under the same conditions    22 min. 
Rewind time with 5 reel (19 cm/s) with 35µm tape   20 min. 
 
 
 
  
						

							TAPE TRANSPORT 
 
Switchable nominal speeds 
 
 15  ips 38.10 cm/s 
 7½ ips 19.05 cm/s 
 3¾ ips 9.525 cm/s 
 
Stability of the nominal speed with respect to the temperature (within the specified range), the 
position of the recorder, the distribution of the tape between the reels, and the supply voltage ±0.1% 
 
WOW AND FLUTTER 
 
Weighted peak-to-peak value, in accordance with  
DIN 45 507/ANSI 4372 
 
 at 15 ips 38.10 cm/s ±0,05 % 
 at 7½ is 19.05 cm/s ±0.07 % 
 at 3¾ ips 9.525 cm/s ±0.12 % 
 
AMPLIFIER CHAIN 
 
NAGRA 4.2 with QPSE-200-XOYO preamplifiers 
 
Overall frequency response, 200 Ohm microphone 
input, line output without load from 50 Hz to 20 kHz ±1 dB 
 
Total distortion at 0 dB, 10 mV input, output load 600 Ohm 
						

							 
FILTERS 
 
 LFA 1 (low frequency Attenuation 
 attenuation)  4 dB at 50 Hz 
 LFA 2  8 dB at 50 Hz 
 HP 1 (high-pass) 10 dB at 50 Hz 
 HP 2 20 dB at 50 Hz 
 HP 1 + LFA 1 (combination) 14 dB at 50 Hz 
 
 
REFERENCE GENERATOR 
 
1.1 kHz sine wave signal with 10 kHz component 
 
 0 VU level= -8 dB ±0.1 dB 
OUTPUTS 
 
Line output voltage on 600 Ohm for 0 dB on the modulometer 4.4 V 
 
Line output impedance   at 30 Hz 90 Ohm 
 at 50 Hz 42 Ohm 
 at   1 kHz 18 Ohm 
 at 15 kHz 24 Ohm 
 
Maximum output voltage on 600 Ohm, 
 
for 1% distortion at  1 kHz 10,5 V 
 at  5 kHz 10,5 V 
 at 30 Hz          7,0 V 
 
Headphones output voltage on 50 Ohm, adjustable from 20 to 500 mV 
 
Output voltage at MIXER connector, on 100 k Ohm, for 0 dB on the modulometer 560 mV 
 
Output voltage of the pilot signal 
 
 with QSLI synchronizer    1    V 
 without synchronizer 350 mV 
 
BUILT-IN LOUDSPEAKER 
 
Power output of the amplifier 1 W 
 
OPERATING CONDITIONS 
 
Temperature 
 with manganese batteries - 4 to + 160  degrees F 
 -20 to +  72  degrees C 
 with external power -67 to + 160 degrees F 
 -55 to +   71 degrees C 
 
The recorder operates correctly in any position.  
						

							MODULOMETER 
 
Integration time for - 2 dB 7.5 ms 
Usable scale -30 to +5 dB 
Frequency response 
 from 40 Hz to 20 kHz ±0,5 dB 
 
RECORDING AND PLAYBACK CHAIN 
 
Nominal recording level 0 dB= 320 nWb/m 
 
Maximum peak level (M.P.L.) + 4 dB 
 
 
Magnetic tape used for Calibration : 
 
 CCIR  LN PEM 468 
   STD PER  368 
 
 NAB  LN 3M 808 
   STD 3M 806 
 
Erasing efficiency 
 
  CCIR 84 dB 
  NAB 88 dB 
 
Frequency response, recording at 20 dB below M.P.L. 
 
15 ips (38 cm/s) CCIR and NAB   30 Hz to 20 kHz  ±1.5 dB 
7½ ips (19 cm/s) CCIR and NAB  30 Hz to 15 kHz  ±1.5 dB 
3¾ ips (9,5 cm/s) CCIR and NAB 30 Hz to   8 kHz  ±2.0 dB 
 
Distortion at M.P.L : 
 
 CCIR 3rd harmonic 0,4% 
  2nd harmonic 0,3% 
 
 NAB 3rd harmonic 1,0% 
  2nd harmonic 0,4% 
 
Signal-to-noise ratio of the playback chain only, with motor running and leader tape, ASA A 
weighted, M.P.L 83 dB 
Recording-playback signal-to-noise ratio at M.P.L at 7½ ips 
 
    ASA A 
   Linear Weighted 
 
 LN NAB 64 dB 73 dB 
  CCIR 62 dB 72 dB 
 
 STD NAB 64 dB 70 dB 
  CCIR 62 dB 68 dB 
 
 
 
 
 
  
						

							INPUTS 
 
NAGRA 4.2  
with QPSE-200-X0Y0 preamplifiers 
 
Microphone input 1,200 Ohm 0.2 to 43 m V 
Microphone input 2,200 Ohm 0.2 to 43 m V 
 
Unbalanced line input, impedance 100 k Ohm 
admissible voltage 0.37 to 120 V 
 
Unbalanced line input at accessory connector, 
admissible current  3.7 to 1,200 µA 
 
Mixer direct input, impedance 9 k Ohm 560 mV 
Pilot input, impedance 5 k Ohm  0.5 to 25 V