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INTRODUCTION SAM-1C
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The SAM-1C has a modular design and can therefore be offered in different versions. Due to the service-
friendly design, the amplifier modules including all sockets can be exchanged or extended subsequently in
a few minutes without soldering.
All inputs outputs have spindle trimmers on the rear panel of the unit, with which the amplification can be
adjusted very precisely for each channel separately from the outside.
During the development of the SAM-1C, special attention was paid to lowest noise (dynamic range at
amplification 1 : typ. 136 dB !) and minimal distortion with a very broadband design of all amplifier stages.
The THD distortions in the important mid-range are typically below - 130 dB at signal levels between
-10 dB...+12 dB! This could only be achieved by using several operational amplifiers per balanced input
and "instrumentation amplifier technology". An excellent phase response of typ. less than 1° in the range
of 10 Hz...20 kHz and a large signal bandwidth of more than 100 kHz guarantee excellent impulse
processing (see also chapter AUDIO SIGNAL QUALITY).
The SAM-1C can also be used for matching time code signals due to its exceptional bandwidth of over 200
kHz. The excellent crosstalk attenuation of over 125 dB at 1 kHz and 120 dB at 10 kHz between the two
channels also allows the use of both signal paths for different mono signal sources simultaneously.
Due to the very high common-mode rejection of the balanced input amplifiers of typ. 120 dB at 1 kHz,
interferences interfering with the balanced line are almost completely eliminated.
The prerequisite for the exceptionally high common-mode rejection or symmetry of the amplifiers used is
our laser-trimmed precision networks on ceramic carriers.
The balanced inputs of the SAM-1C can also be operated asymmetrically at the input without any
problems, e.g. for use as an asymmetrical catch-up amplifier impedance converter, phase reversing stage
or for "hum loop elimination" see also chapter HUMBLE ELEMENTS.
Once the output level has been set, it remains constant due to servo balancing with balanced and
asymmetrical wiring of the XLR outputs. In contrast to many other balanced amplifier circuits, the
maximum achievable output voltage (headroom) of the SAM-1C does not decrease with asymmetrical
wiring of the balanced output! This results in a further improvement of the dynamic range compared to
comparable balancing amplifiers of typ. 4..6 dB when the outputs are operated in unbalanced mode.
Flawless operation is guaranteed at all balanced outputs up to 300 Ohm output load.
The unbalanced inputs outputs are connected via gold-plated cinch sockets. The balanced inputs outputs
are connected to XLR sockets with gold-plated contacts.
1.2 Pin assignment of t e XLR sockets :
Pin 1 is audio ground
Pin 2 is the +in output of the amplifiers
Pin 3 is the -input output of the amplifiers
All balanced inputs and outputs are
equipped with NEUTRIK XLR sockets. The
pin assignment is as usual in professional
technology (see picture). Circuit zero
(ground) and earth (enclosure) are
separated from each other to achieve
greater freedom when installing in different
systems.
1.3 Rear view SAM-1C :
Compared to the predecessor models SAM-
1A and SAM-1B, the SAM-1C is equipped
with a standard mains socket for mains
cables. The power switch is also located on
the back of the unit.
