SoundCraft POWERSTATION 1200, User Manual

Page: 9 / 20

Page 9
SUB-SONIC FILTER
An 18dB/octave 40Hz SUB-SONIC FILTER may be switched into the feed
to the amplifier, and for most applications it is recommended that this filter
be switched in. Using the filter avoids potential loss of control in PA cabi-
nets with reflex ports when driven below their frequency range, and offers
some protection against damage from heavy ultra-bass signals.
Switching the filter into circuit is almost always a good idea, but may unnec-
essarily restrict the dynamic range of a system with particularly wide-range
PA cabinets, and should be switched out if very low frequency rumbles are
specifically required and the speaker system has the capability. The filter
also allows you to use your LF boost to warm up the bottom end of your
mix without the usual problems of bass distortion.
RECORD OUTPUT
The RECORD OUTPUT, on RCA phone sockets, provides a -10dBV pre-
mix-fader (post insert feed), for recording. Since the signal is derived after
the insert, a compressor can be included in the signal path if required.
LOUDSPEAKER OUTPUT TERMINALS
The power amplifier output is available on standard dual banana terminals
and ‘speakon’ connectors on the rear of the mixer.
Minimum recommended load impedance is 4
W but
the amplifier guards itself against damaging overload,
switching in the protection systems when necessary.
While this will maintain safe operating limits, the
result will be serious distortion and a very unmusical
sound. Always follow the load recommendations
where possible.
To avoid damage to the amplifiers DO NOT GROUND
any of the Loudspeaker output terminals, or connect
any terminal to any other terminal.
Multiple speaker config-
urations may be used,
but load impedance
should be maintained
above 4 W . It is there-
fore important to
understand the differ-
ence between SERIES
connection (imped-
ances ADD) and PAR-
ALLEL connection
(impedances are divid-
ed) as shown in the
illustrations.
STEREO
RETURN
FX
BUS
L/R
BUSSES
2 TRACK
RETURN
TO
POWER
AMP
MIX
L/R
EFFECTS
MIX
INSERT
GRAPHIC
EQUALISER
MIX
OUTPUT
NORMALLING NORMALLING
GRAPHIC EQ
INPUT
GRAPHIC EQ
OUTPUT
POWER AMP
INPUT
LEVEL
LEVEL
LEVEL
LEXICON
DIGITAL
EFFECTS
CONTROLLER
MIXER OUTPUTS
SIGNAL FLOW DIAGRAM
To external
amplifier
Example 1
Example 2
Example 3
Left Power Amp Output = Main Out
Right Power Amp output = Foldback
Pre Graphic
Equaliser Post Graphic
Equaliser
From external
mixer to EQ
From mixer
From external
mixer to PA
no EQ
PATCHBAY
The line level mixer outputs, inserts and returns are arranged together on
the top right of the mixer. For maximum flexibility the inputs to the Mixer,
Graphic Equaliser and the Power Amplifier are available separately to allow
replugging for particular purposes. The three sections are ‘normalled’
together by the internal switch contacts on the jacks, as shown in the dia-
gram.
The normalling is broken as soon as a jack is inserted, allowing the signal to
be re-routed as required. Note that separate left and right jacks are pro-
vided for all signals shown in the diagram above . Only one side is shown
for clarity.
PATCHBAY APPLICATIONS
The flexibility of the POWERSTATION Patchbay is illustrated with three
examples:
Example 1
Feeding an external amplifier, either pre- or post-Graphic Equaliser.
Normalling is unaffected. The output acts as a “Y” splitter, one feed to the
internal amplifier, the other to the external amplifier.
Example 2
Feeding the amplifier from an external mixer, for a secondary band perhaps,
plugging directly into the power amplifier jacks. Alternatively the external
feeds could plug into the Graphic EQ Inputs jacks, providing some signal
correction if required. Alternatively you can add the external signal/mixer
to the Powerstation’s MIX using the Stereo Return or any line level input.
Example 3
If only a mono PA output is required, one channel of the power amplifier
can be fed from the Mono Output by overplugging as shown, and the sec-
ond channel may be used to drive, for example, foldback from Aux 1. In
both cases the Graphic EQ is left in the signal path.
Ω
Ω Ω Ω
Ω + Ω = Ω
Ω ÷ Ω
Ω ÷ Ω
Ω
Ω
Ω
Ω
Ω
Ω
Ω
Ω