I N S T A L L A T I O N I N S T R U C T I O N S
4.35
Ground Loops (continued)
e) BREAKING A GROUND LOOP WITH AN AUDIO ISOLATION TRANSFORMER
In cases where the ground loop can not be broken due to a 3rd wire safety ground as the sec-
ond part of the ground loop, an audio isolation transformer can be inserted into the audio sig-
nal line. This can be required in unbalanced audio connections with signal and ground. The
use of transformers may not be desirable, but is sometimes the best solution.
f) BREAK A GROUND LOOP WITH A BALANCED INPUT
If a ground loop is being completed by the ground in an unbalanced device, it is possible to
break the loop by taking the ground of the audio output into the balanced input of another
device. If it is not possible to use a transformer to break a ground loop then a balanced distri-
bution amp is a possible solution.
Signal
Ground
(+)
(-)
ACTIVE BALANCED
AUDIO INPUT
UNBALANCED
AUDIO OUTPUT
CHASSIS
GROUND
SHIELD
Ground
CORRECT
Signal
Ground
(+)
(-)
ACTIVE BALANCED
AUDIO INPUT
UNBALANCED
AUDIO OUTPUT
CHASSIS
GROUND
SHIELD
Ground
WRONG