Changing the Plug-in Preamplifiers
These preamplifiers are coupled to the rest of the Nagra by a connector. They are physically held in
place by a small screw accessible from the bottom of the recorder.
On turning the Nagra over, that is, placing it on its cover with the battery compartment upwards, the
screw for preamplifier No1 can be seen, on the left viewed towards the front panel. Immediately to
its right is the screw for preamplifier No 2. Once these screws have been removed, the Nagra can
be opened. To do this, unscrew the two fasteners, which fix the tape deck to the box (on the right-
hand side of the recorder). Turn them in the direction "Open" until the tape deck disengages itself.
Open the Nagra. Remove the preamplifiers, which are immediately behind the meter, simply by
pulling.
Plug-in Preamplifiers
"LINEAR STANDARD -200" Code: QPSE-200-X0Y0 and "STANDARD 50" Code: QPSE-50-
X0Y0
These preamplifiers are similar to "STANDARD" type but have no filter incorporated. Their
frequency response is flat from 30 Hz and the attenuation at 20 Hz is in the region of 2 dB.
"HIGH GAIN STANDARD 200" Code: QPSE-200-X6Y3 and "HIGH GAIN STANDARD 50" Code:
QPSE-50-X6Y3
These preamplifiers are similar to the "Standard" type but their gain is double (+6 dB) whereas their
attenuation of the low frequencies is slightly greater (3 dB at 50 Hz). The maximum voltage, which
they can receive, is 20 mV for 200 Ohm and 10 mV for 50 Ohm.
For the application of these preamplifiers see Section 5.6.
"STATIC 5" Code: QPM-3-5
This preamplifier is designed to receive the signal from the Sennheiser condenser microphones
type MKH 105, 405 and 805, Neumann type KM 73, 74, 76 and Schoeps type CMT 40.
At the same time, these microphones are powered from the Nagra. This preamplifier is also
designed to operate in conjunction with the cable preamplifier type QPLE, which is placed close to a
dynamic microphone. The combination of a dynamic microphone plus a QPLE is electrically
equivalent to a microphone MKH 105 etc. It is thus possible, when a Nagra is equipped with "Static
5" to place either a condenser microphone or a dynamic microphone with the QPLE at the end of
the microphone cable.
Sensitivity: 2 mV gives 0 dB when the gain is maximum.
Attenuation of low frequencies: adjustable by steps of 3 dB at 50 Hz up to -15 dB by a built-in
switch. To operate this switch, it is necessary to open the Nagra.
Maximum Input Voltage: 200 mV.
Distortion and noise level: negligible, compared with those of the microphone.
Temperature range: -55
?
to +71
?
C (-67
?
to + 160
?
F)
"HIGH LEVEL LINE" Code: QPM-6
This preamplifier transforms the microphone input into a symmetrical floating line input. Input
Levels: 0.1 to 24 V R.M.S. Impedance: 10 k Ohm.
(on special order only)
"UNIVERSAL" Code: QPAUT & QPUT
These preamplifiers are designed to accept dynamic 200 Ohm, "Phantom" +12 V or +48 V and "T"
p10 V condenser microphones.
