Radio Systems DA 2x4a, Руководство пользователя

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R a d i o S y s t e m s , I n c . D A - 2 / 4 x 4 a M a n u a l
3 / 0 4 P a g e 3
Overview
The Radio Systems DA-4x4a is designed to function as a super low noise, low distortion
audio distribution amplifier which may be user wired to function in various flexible input
and output configurations.
Excellent isolation is provided between outputs. Each balanced channel, regardless of
level set and load, is unaffected by the other channels. The Radio Systems DA-4x4a
Distribution Amplifier allows audio sources to be routed to multiple locations with
various level requirements and impedances while maintaining the integrity of signal
quality throughout.
The distribution amplifier is configurable to a dual channel, 2x4 output version, or quad
channel, 4x4 output version.
Mounting
The 4x4a occupies only 1 rack unit (1-3/4 inch) of height in a 19 inch EIA rack. To allow
for adequate ventilation, avoid mounting the unit directly above large heat producing
equipment such as power amps or power supplies.
When stacking units, it is recommended that one rack space (1-3/4 inch) remain open
between every three units.
Operation
Apply an input level of approximately 0dB to the input terminals. The gain of any stage
may be increased by 20dB in 10dB steps by changing the internal gain straps.
To locate and reset these jumpers, refer to the parts layout for the location of JU1 and
JU2. The lid of the unit must be removed to access these jumpers. Place a shorting strap
across the center and rear pin (pin towards the rear barrier strip) to increase input gain by
10dB. Place a shorting strap across the center and forward pin to increase input gain by
20dB.
Output level is factory set for unity gain. Each output can be individually set via its front
panel recessed level pot over a range from –60 to +18dBm. Nominal operating levels
are 0dBm input and +10dBm output. Higher operating levels can cut dynamic range by
operating too close to the clipping point. Adjust each output to the desired level,
keeping clipping in mind.
Connections
The units are primarily designed for balanced inputs and outputs. The input ground is
connected to the chassis and power supply at a single point. If unbalanced lines are
used, tie the unused input terminal to ground. However, do not tie any unused output
terminals to ground. Wire an unbalanced output between one output terminal and the
input ground terminal. For further details, see the section on using active balanced
circuitry in this manual.
Although the outputs are short circuit protected, operating into less than a 600 ohm load
is not recommended. The input is bridging (high impedance) and will not load down any