Peavey CS 1800G - Manual (Page 5)

Back Panel:
BACK PANEL FEATURES:
MAINS POWER SOURCE (6) 120 V products only
The CS
is fitted with a single heavy-duty AWG line cord and a conventional AC plug with a
large ground pin. It should be connected to an independent mains circuit capable of supporting at least I.5 amps con-
tinuously or greater. This is particularly critical for sustained high power operation. If the socket used
not have
a ground pin, a suitable ground lift adaptor should be used and the third wire grounded properly. Never break off the
ground pin on the CS
power amplifier. The use of extension cords should be avoided, but if necessary, always
use a three-wire type with at least a AWG wire size. The use of lighter wire will severely limit the power capability
of this amplifier. Always use a qualified electrician to install any necessary electrical equipment. To prevent the risk of
shock or fire hazard, always be sure that the amp is properly grounded.
GROUND LIFT SWITCH (7)
This switch is used to disconnect the CS
“signal ground” (both input and output) from the “chassis ground.”
Chassis ground is the chassis itself, which is electrically grounded through the rack mounting screws to the external
rack system and through the mains line cord via the large ground pin to the mains ground. It is often advantageous to
“lift” the signal ground from chassis ground to eliminate a “ground loop” which has caused unwanted ground current in
the signal cables between the external preamp and this power amplifier. Such conditions can create excessive hum
levels in the power amplifier output and render the system useless in low level applications. In this case, “lifting” the
ground should solve this hum problem. Ground lift is selected when the switch is in the right or “LIFT” position. If
lifting the ground does not eliminate a particular hum
then we recommend you defeat the ground lift feature.
NOTE: Using this ground lift feature still leaves the chassis itself grounded electrically through the mains line cord.
Having the chassis grounded avoids any possibility of an electrical shock or a fire hazard. This ground lift feature
should never be confused with the practice of “floating” the large ground pin at the AC mains receptacle to eliminate a
ground loop. Floating the ground pin on any electrical equipment is just asking for trouble!
SPEAKER OUTPUTS (8)
Two each jacks and binding post speaker output terminals are provided. All these outputs
A
are in parallel, hence the speaker connection cables can be terminated with phone plugs, banana
plugs, or stripped wires for use in the binding post terminals. For sustained high power applications,
the use of the binding post terminals are recommended; however, care must be exercised to assure
correct speaker phasing. Regardless of what connections are used, the typical parallel speaker load
should always be limited to 2 ohms per channel or 4 ohms Bridge mode for any application.
Operation at loads of 4 ohms per channel or 8 ohms Bridge mode is more desirable for sustained
operation applications due to the fact that the amplifier will run much cooler at this load. Operation
above 4 ohms per channel, and even open circuit conditions can always be considered safe; however,
any sustained operation at loads below 2 ohms could result in temporary channel shut down due to the
thermal limits and/or the amp fault circuits.