4
II. Specifications
Input Impedance:
10K or 50 ohm balanced/unbalanced selectable
Output Impedance:
50 ohms unbalanced
Maximum Output level:
4 Volts Peak to Peak into 50 ohms
Gain:
6
dB
variable
Frequency Response:
Better than +/- 0.05 dB from 20 Hz to 100 kHz
Total Harmonic Distortion:
Better than 0.05% into 50 ohms
Inter - Modulation Distortion:
Better than 0.05% S.M.P.T.E. 4:1
System Noise:
Better than 80 dB below 4 Volts Peak to Peak
Input Connectors:
2 - Isolated B.N.C.
Output Connector:
B.N.C. (2 rear, 1 front panel)
Power
Requirements:
120/240 Volts A.C. 50 - 60 Hertz
Operating Temperature Range:
0 - 60
°
Celsius non condensing atmosphere
Physical Dimensions:
1.75 H X 19 W X 10 D (inches)
III. Installation
A. Initial Configuration
Before installing the unit it is a good idea to decide whether or not the unit will operate balanced
or unbalanced and/or bridging or terminated at its input. Generally, to avoid ground loops
between equipment it is advisable to operate the unit in the balanced configuration. If for some
reason it is desired to operate the unit unbalanced or to terminate the input to 50 ohms, locate
the rear panel four position DIP switch. Push the switch section marked terminate down. If
unbalanced inputs are desired, push the switch position marked unbalanced down. The other two
switch positions have no function on this unit.
The unit as configured from the factory is set to accept 120 Volts A.C. 60 Hertz electrical power.
To change the power setting, first remove the power cord from the power entry connector. Slide
the plastic cover to the left and with a pair of long nosed pliers carefully remove the power select
p.c. board from the power entry module. Select the desired power configuration by placing the
power entry p.c. board back into the module so that the desired power setting can be read from
left to right.
B. Location and Hookup Considerations
Locate the CDS-300 in a 19-inch E.I.A. standard rack enclosure in close proximity to the
equipment that it is going to interface between. Allow sufficient airflow space between equipment
to allow for proper cooling. It is important that the cables being fed from composite sources such
as stereo generators and STL receivers be kept as short as is practical. The CDS-300 can drive
lines as long as 25 feet with no degradation of signals. It is advisable to keep all cable lengths as
short as possible to prevent stray R.F. pick up.
C. Composite Connections and Adjustments
Make all desired input and output connections to your external equipment. Make sure that the
CDS-300 is plugged in to a properly grounded A.C. receptacle. If possible, interrupt the audio
feeding the CDS-300 and measure the signal to noise ratio with a suitable voltmeter. If the noise
measurement obtained is acceptable you can proceed to the final adjustment of the unit. If the
noise is high there may be stray R.F. pick up or a ground loop. It is a good idea to listen to the
system with a suitable audio monitor to determine the source of the noise. Hum is a common
noise present. If hum is present, start by removing one cable at a time to determine the source of
the ground loop. If the hum disappears or changes level when a cable is disconnected, a loop
exists between the CDS-300 and the equipment at the other end of the cable removed. This will
