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Whirlwind AS8X4
The AS8X4 Active Splitter is a 1 rack space, 8-channel active microphone splitter
providing 4 isolated outputs per channel. It features:
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Professional quality mic preamps driving premium quality Lundahl LL1581XL
transformers. This eliminates microphone loading effects characteristic of passive
splitters
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4 transformer isolated outputs optimized for transmitting audio down long cables
All I/O connections via plug-in Phoenix style screw type terminal strips
48-volt phantom power with on/off switch and indicating LED provided on each
channel
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20dB input pad
Listen (cue) feature on each channel
LED headroom indicators on each channel
Ground lift switches on all isolated outputs
Internal switches allow 3 different gain settings of the mic preamp
2 additional internal jumpers (user changeable without soldering) engage post mic
preamp 20dB pads for flexibility in setting different gain structures for various
cable lengths
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Up to 80 channels of split are capable with multiple units and the appropriate
power supply
Modular design allows for future expansion and individual units are easily
changed in the unlikely event they need servicing
Power supply and monitor are a separate unit and utilize various wattage supplies,
depending on the number of channels in the system
Monitor section features a high power headphone driver and VU meter for instant
cueing of individual channels
Description of Block Diagram
All audio input and output connections are done via a plug-in type Phoenix style screw
type barrier strips. Each inline strip accommodates 4 channels. On the back panel, all
input and iso outputs are separate groups. The strips allow termination of wire ends
without the splitter unit present and provide for quick and easy connect/disconnect. The
Direct IN/OUT terminations, which accept a mic level input, are used for generating a
direct-wired parallel output should a 5-way splitter be desired.
Each channel has its own phantom power on/off switch with LED indicator. When
engaged, 48 volt phantom power is placed on the Direct IN/OUT + and – terminals. The
individual phantom power on/off switches allow worry free hook up to electronic
equipment not able to block the 48 volts DC.
After the input, the signal passes thru a 20dB pad. This allows input of line signal levels
up to +20dBm.
The rear panel contains:
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5 terminal strips - Direct IN/OUT and Iso 1-4. Each of the wire end screw type
terminals handles 4 channels
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Individual ground lift switches for every Iso output on the unit
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A 9-pin DSUB connector that connects the monitor unit and supplies DC power
to the AS8X4
As8x4 MONITOR UNIT
The monitor unit is available with various wattage power supplies depending on the
number of channels needed in the system. The units are available in 2 configurations,
rack mount with the supplies mounted to the rack panel, or a 2 space rack unit for the
monitor section only with the supplies located in a separate Hoffman box with multipin
connects. The monitor unit can be configured to handle up to 10 AS8X4 splitter units or
80 channels.
Specifications:
Frequency response
Total harmonic distortion + noise
Phase shift
Equivalent input noise
Total gain
± .15dBv 31Hz - 18KHz, -3dBv at 20Hz, -1.53dBv at 20
.0019 % at 1KHz –14dBv
.4 degrees at 1KHz
120dBv
40dBv
Gain of microphone preamp
Common mode rejection of input
Maximum input level
20, 30 or 40dBv selectable
90dBv at 60Hz
0dBv
Input impedance
1.2K Ohms
Maximum output level
Output impedance
Headphone output impedance
Minimum impedance of headphones
Noise at unity gain
+22dBv
80 Ohms T pad on, 22 ohms T pad off
13 Ohms
30 Ohms
-116dBv
Noise at 40dBv of gain no T pad
Noise at 30dBv of gain no T pad
Headroom LED threshold
Phantom power
-80dBv
-89dBv
0, -12 –24dBv
+ 48 volts DC
+8dBv
Max output of headphones at 30 Ohms
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