SoundCraft POWERSTATION 1200, Руководство пользователя

Страница: 8 / 20

Page 8
LEXICON MUTE FOOT SWITCH
The Effects may be turned ON or
OFF remotely by connecting a stan-
dard latching or non-latching guitar
foot-switch, or similar unit providing
an isolated switch closure, to the rear
panel Lexicon Foot Switch jack socket
as shown. The Effect is muted when
the switch is closed.
GRAPHIC EQUALISER
GRAPHIC EQUALISER
The stereo GRAHIC EQUALISER is
normalled to the Mix L/R outputs.
Seven frequency bands, with cut or
boost of 6dB, allow very precise glob-
al control over subtle tonal changes to
the PA rig in a particular room. (This
is in contrast to the much more dan-
/-12 or +/-15dB offered on some other units where a deceptive-
ly small movement of the faders can result in feedback or similar unwanted
effects.)
The built-in graphic equaliser is intended to trim the overall sound to suit
the room, and is not designed to null out frequencies to prevent feedback.
A full 31-band EQ is recommended for that purpose.
LEFT/RIGHT BYPASS
Each channel of the Graphic Equaliser may be bypassed by pressing the
LEFT BYPASS or RIGHT BYPASS switches. This allows a direct compari-
son to made of the treated signal (with EQ) and untreated signal, to judge
the effect of the Graphic EQ settings.
+48V
Many professional condenser microphones need Phantom Power, and this
can be supplied to all of the Mic input connectors by pressing the +48V
switch.
ONLY connect condenser microphones with the +48V
powering OFF (switch UP), and ONLY turn the +48V
powering on or off with all output faders DOWN, to
prevent damage to the mixer or external devices.
TAKE CARE when using unbalanced sources, which
may be damaged by the phantom power voltage on
pins 2 & 3 of the XLR connector.
8
CAUTION
RISK OF ELECTRIC SHOCK
DO NOT OPEN
Switch open
= Effect ON
Switch closed
= Effect OFF
DO NOT apply any
external voltage to
the jack socket
STATUS INDICATORS
Three LEDs provide visual indication of the status of the mixer.
POWER
The POWER (green) lights to show that power is switched on, and senses
the power amplifier voltage rails.
THERMAL
The THERMAL (yellow) indicates that power amplifier over-temperature
has been detected.
MUTE
The MUTE (red) lights when the power amplifier output relays are open.
This happens momentarily on power-up to isolate surges as the power rails
stabilise, or will happen if the protection circuits detect a d.c. fault situation
or overheating, in which case the relays will open as protection for the
loudspeakers.
If a d.c. offeset or overheating is suspected, check that the air vents at the
front and rear of the mixer have not been inadvertently covered.
POWER AMPLIFIER
The Power Amplifier contains no user-serviceable
parts. Refer all servicing to a qualified service
engineer, through the appropriate Spirit dealer
The POWERSTATION contains an integral power amplifier, the inputs to
which are normalled to the Graphic Equaliser outputs, or may be accessed
directly via the Power Amp Input jacks. The amplifier incorporates a
sophisticated protection system which guards against overheating, to pro-
tect the output transistors, and isolates the speaker outputs via relays if a
damaging fault condition is detected in the output stage. The amplifier is
cooled by a variable speed “music-sensing” fan which senses the output sig-
nal level and delivers greater airflow as the signal level, and corresponding
heat dissipation in the output devices, increases. When there is no signal or
a very low level signal, the fan will be running very slowly and quietly.
Air is drawn in along the front of the unit and expelled through vents at the
left-hand side at the rear. It is important that sufficient clearance is allowed
at the front and rear of the mixer to ensure unrestricted airflow, especially
in rack-mounted or flight case installation.
WARNING
Do not obstruct air vents.
POWER AMP OUTPUT LEVEL
The signals from the balanced Power Amp Inputs jacks (normally the out-
put from the Graphic Equaliser) are fed via the POWER AMP LEVEL con-
trol to the integral stereo power amplifier. Use this control to set the level
to your speakers, as with any amplifier level control.