4
DRAWMER
1978 O
PERATOR’S
M
ANUA
L
The 1978 is designed for standard 19" rack mounting and
occupies 1U of rack space. Avoid mounting the unit directly
above power amplifiers or power supplies that radiate
significant amounts of heat and always connect the mains
earth to the unit. Fibre or plastic washers may be used to
prevent the front panel becoming marked by the mounting
bolts. It is also advisable to leave space above the unit to
allow the heat to dissipate.
INSTALLATION
AUDIO CONNECTIONS
The inputs and outputs are electronically balanced on conventionally wired XLRs (pin 1 screen, pin 2 hot, pin 3 cold and
XLR shell is connected to chassis). The operating level is nom4dBu. Balanced use is recommended.
• Interference:
If the unit is to be used where it maybe exposed to
high levels of disturbance such as found close to a TV
or radio transmitter, we advise that the unit is operated
in a balanced configuration. The screens of the signal
cables should be connected to the chassis connection
on the XLR connector as opposed to connecting to
pin1. The 1978 conforms to the EMC standards.
• Ground Loops:
If ground loop problems are encountered, never dis-
connect the mains earth, but instead, try disconnect-
ing the signal screen on one end of each of the cables
connecting the outputs of the 1978 to the patchbay. If
such measures are necessary, balanced operation is
recommended.
1978 CONNECTOR WIRING
SIDE CHAIN
The external side chain feature on the 1978 is part of the compressor feedback stage and would normally be connected
to a normalised or semi-normalised pair of patchbay contacts. This would allow the user to insert EQ in addition to the
Tonal shaping on the front panel for some de-essing, or frequency conscious compression. The side-chain access point
is unbalanced, connection is via stereo 1/4" jacks, the wiring convention being: ring is signal send, tip is signal return
and sleeve ground.
