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FLOATED EQUIPMENT
Units with a 2-pin mains power cord have no means to connect the audio output ground to earth ground, so usually the
audio output ground is floated from earth ground. However, this does not insure that when installed in a system, the audio
output ground will remain floated from earth ground. The input cable to this equipment may already be connected to earth
ground earlier in the audio chain, and it will typically be carried straight through to the output. It is also possible that the
audio output ground connects to the earth ground through the chassis to an earth-grounded rack. The only way to know for
sure is to test the installed system. Use an ohmmeter to check for continuity between the earth ground socket of the mains
power receptacle and the audio output ground.
If the audio output ground is not connected to earth ground, it is floated
equipment.
Consult the following diagrams for examples of recommended wiring techniques:
The output XLR jack accepts a female XLR plug and provides a hard-wired pass-through of all 3 pins of the input jack.
DELAY
(One of these switches must be selected. If all the switches
are OFF, there will be no output signal.)
The delay feature provides five sections of 2nd-order all-pass delay
filters of 450µsec +/-10µsec each. Unlike the more commonly used
1st-order all-pass, the 2nd-order filters achieve a constant delay time
over the usable frequency range of 1Hz to 1kHz. At frequencies
higher than 1kHz, the gain remains flat, while the delay time gradu-
ally decreases to zero.
The delay time is labeled in inches of delay (i.e. 450µsec/section X
1130ft/sec X 12 inches/ft = 6 inches/section). If there is uncertainty
about the amount of delay needed, choose the 0” switch.
CROSSOVER
A 3-position slide switch selects the High-Pass (HP), Low-Pass (LP), or Full-Range (Full) configuration of the 4th-order
crossover.
FREQUENCY
The crossover frequency can be selected as either 500Hz or 800Hz.
Shield
Chassis
Audio
Ground
XLR, 1/4" TRS Amplifier
SHIELDED TWISTED PAIR
FLOATED,
BALANCED
SOURCE
shield connected at both ends
1
3
2
Shield
Chassis
Audio
Ground
XLR, 1/4" TRS Amplifier
SHIELDED TWISTED PAIR
FLOATED,
UNBALANCED
SOURCE
shield connected at both ends
1
3
2
Shield
Chassis
Audio
Ground
XLR, 1/4" Mono Amplifier
1/4" Mono: sleeve shorts
— input to Audio Ground;
XLR: short pins 1 & 3 together
COAX OR TWISTED PAIR
FLOATED,
UNBALANCED
SOURCE
2
3
1