Operating instructions

TRANSFORMER
BALANCED INPUT
DEVICE
CONSOLE
LINE OUTPUT
(+)
(-)
SHIELD
CHASSIS
GROUND
(+)
(-)
Zout
<100½
255½ MATCHING RESISTORs
3-4c) CONSOLE BALANCED OUTPUT TO TRANSFORMER BALANCED INPUT
The console Output is low impedance (<100 ohms) and can therefore directly drive only ONE 600½ input impedance transformer
balanced input without a distribution amplifier. The transformer needs to see a 600 ohm balanced driving impedance for accurate
frequency response and low distortion. Each console Output has a 47½ series resistance already built in. This means that a 253 ohm
(255 ohm is the closest standard value) series resistor must be added to each leg of the balanced console output as shown below.
3-4d) CONSOLE BALANCED OUTPUT TO ISOLATION TRANSFORMER TO UNBALANCED INPUT
In some situations an Isolation Transformer is required to solve tough RF Interference or ground loop problems where the Input Device
is unbalanced. The Isolation Transformer must be impedance matched to both the console and the Input Device . Typically
a 600ohm audio transformer is used whose inputs and outputs want to see a fixed impedance of 600½ for it to meet frequency
response and specifications. The Console Ouput is low impedance (<100 ohm). To match impedances, distortion a 253 ohm series
resistor must be added to each leg of the console output as shown above. A 600 ohm resistor must be placed across the input of the
Input Device (as shown below) assuming the Input Device is high impedance. Place the transformer close to the console output.
(+)
(-)
ISOLATION
TRANSFORMER
CONSOLE
LINE OUTPUT
SHIELD
CHASSIS
GROUND
Zin
>10k½
UNBALANCED
INPUT
Zout
<100½
(+)
(-)
INPUT
ELECT.
GROUND
600½
MATCHING RESISTOR
Arrakis Systems, inc. --- 6604 Powell st., Loveland, CO 80538 --- 970-461-0730 --- www.arrakis-systems.com
INSTALLATION PROCEDURES
OUTPUT WIRING (continued) 3-4)
3.13