Crest Audio HP-EIGHT, Owner'S Manual

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power supply
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p. 71
Power Supply - External
External Power Supply
The style and pinout of the DC Connectors on the HP-Eight are the same as the Crest X-Series of consoles (X-Eight, X-
Four, X-VCA, X-Monitor), and the existing X-Series supply CAN be used to power the HP-Eight console.The voltage
requirements are the same, but the current demands are less with the HP-Eight.
The better (and cheaper) solution for an external supply is to use the supply designed for the HP-Eight, the model XPS-
SW3.This external supply uses the same basic PSU assembly from the HP-Eight, fitted in a 2U chassis.The rack-mount
faceplate can be removed if a stand-alone, floor or desk mounted supply is desired.AC power requirements are the
same, any world-wide voltage can be used to power the supply.
Power Supply Controls - Front
Power
When this switch is ON,AC power is supplied to the internal circuits.
DC Status
These four green LEDs show the condition of the four main DC supply voltages present on the rear-panel DC output
connector.
Power Supply Controls - Rear
AC Input
This is a standard, 15 amp IEC power inlet connector.A mating cord-set is normally supplied with the Console to match
local power requirements.Any world-wide AC mains voltage is acceptable, from 100 volts to 240 volts, 50 or 60 Hz.
Maximum input power is 200 watts.
Fan Guard & Filter
There is a low-speed fan mounted within the power supply.This fan will draw cooling air through the rear filter and
exhaust it through the slots in the sides of the chassis (you won’t feel a lot of air moving).The outer frame of the filter
snaps-off, revealing the filter (foam) material. Occasionally clean the foam (or when you see dust build-up).
DC Output
This 7-pin circular socket connector carries the DC voltages from the supply. It should be connected (via the DC power
cable) ONLY to the DC Input connector of approved Crest Consoles. Even though the power supply is protected
against output abuse, it was specifically designed for Crest mixing consoles. It may not function properly if attempts are
made to power other devices (including other manufacturer’s consoles!).
Ground Link
When using an external supply, the Console’s internal supply is plugged into an AC outlet AND the console is connected
(via the DC cable) to an external supply which has its own AC plug and outlet.These two, different AC outlets may be at
different ground potentials. Depending on various (sometimes unknown) conditions, a “ground-loop” may occur.This usu-
ally manifests itself as a low-level hum in the console outputs.
This barrier-strip is provided to allow the chassis-ground of the external power supply to be lifted from the console
audio-ground, thereby removing the 2nd (loop) path of the Console’s audio-ground to the AC outlet grounds.The
Console’s internal supply ALWAYS has the console chassis-ground and audio-ground tied together inside the console.
Normally, the supplied metal link ties the two barrier-strip ground circuits together.This link can be removed to separate
these two grounds of the external supply to minimize hum.
NOTE:
Removing this link DOES NOT lift the chassis of the external supply from the AC safety ground, the chassis of the power
supply enclosure is ALWAYS attached to the 3rd wire ground of the AC inlet connector.That connection is there for safety reasons- it
shunts (to the AC ground plug) any dangerous internal faults that may contact the chassis metalwork.AT NO TIME SHOULD THIS 3rd
WIRE GROUND BE DEFEATED (by cutting off the AC plug ground pin or by improperly using a ground-lift adapter
).
GROUND
LINKING
CHASSIS
GROUND
CONSOLE
GROUND
DC OUTPUT
(TO CONSOLE)
100-240V
50 / 60 Hz
200W
AC IN
DC VOLTAGE STATUS
+18V
+48V -18V
+12V
ON