Whirlwind LD410, Operation Manual

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1. Input Pad switch applies a 14dB pad across the input jack when depressed.
2. Gain control varies the signal level at the output jacks. The gain markings around the knob
indicate the amount of gain or attenuation being applied to the signal. The bold mark
designates the normal position for +4dB to -10dB conversion on channels 1, 2, 5 and 6 and
-10dB to +4dB conversion on channels 3, 4, 7 and 8. The "0" gain position is unity gain,
balanced input to balanced output.
3. Output Mute switch turns off the output signal when activated. It also illuminates the clip
LED in a steady state to indicate that the channel is muted.
4. LED Indicators show the level of the signal at the output jacks. Green is set to light when
the output signal is at -10dB and yellow illuminates at +4dB. The red clip LED monitors
the signal level both before and after the output gain control. If the clip LED illuminates,
the output gain can be reduced to determine if the clipping is the result of a high input level
or the amount of output gain. (See “Description of Block Diagram” for details.)
5. Power switch applies power to the unit and the Power LED indicates that the unit is
turned on. There is an internal fuse, which if blown, prevents the power LED from
lighting.
6. Female XLR input jacks on inputs 1, 2, 5, and 6 take balanced line level inputs to the
respective channel's preamp section. The output of each preamp can be assigned (via
internal jumpers) to other output channels in addition to the normal output.
7. RCA output jacks on outputs 1, 2, 5 and 6 deliver unbalanced signals from the line drivers and
are controlled by the output gain pots. The RCA outputs may be used simultaneously with the
balanced outputs (see 10) because they have separate driver circuits.
8. RCA input jacks
on inputs 3, 4, 7 and 8 take unbalanced input signals to the respective
channel's preamp section. These jacks are ground floated unbalanced inputs, which parallel
the available balanced inputs (see 10) and can be grounded by connecting a jumper from "G"
to "-" on the screw terminals.
9. Male XLR output jacks on outputs 3, 4, 7 and 8 deliver balanced line level signals from the line
drivers and are controlled by the output gain controls.
10. Screw terminal connections provide balanced signal connections for the channels with RCA
jacks. The RCA jacks on inputs 3, 4, 7 and 8 are connected in parallel across the plus and minus
terminals and can be grounded by connecting a jumper from "G" to "-" on the screw terminals.
The screw terminals on outputs 1, 2, 5 and 6 have separate drivers and can be used
simultaneously with the RCA outputs.
11. Ground lift switch - when depressed, disconnects audio common from earth ground.
12. Internal signal routing jumpers (not shown) allow flexible signal routing from input preamps
to the line driver outputs. Each output is configured at the factory to deliver the signal from the
corresponding input. Changing the jumpers sets up distribution amps, allowing multiple
outputs to deliver the same input signal. (See “Description of Block Diagram”.)