SPL 9945, User Manual

Page: 21 / 28

21
Operation
Displays
Power Supply
Gain Reduct.
The Gain Reduct. display provides information about the processing being
undertaken with the Compressor/Limiter or the Noise Gate.The level change,
perhaps caused by compression, are scaled in 1.5 dB steps. The display is
activated when the Compressor/Limiter module is switched on.
Noise Gate operation is visible because all Gain Reduct. LEDs illuminate
when the signal level lies under the gate threshold setting.
PPM Output
The PPM Output display shows the peak reading of the output level (cali-
brated to 0 dB) and is present at the analog outputs on the rear of the unit.
This display also serves to the pre-amplifying Gain. The value ”0dBFS”
marked on the left side represents the maximum level of the optional AD/DA
converter which should not be exceeded. (Further information is given in
the directions to the AD/DA converter).
Although the values of the PPM Output display only cover up to + 12 dB
sufficient headroom remains internally (approximately 6 dB) so that the
output value can exceed this limit without causing clipping. The range of
optimal noise performance lies between 0 and + 9 dB.
Built around a torroidal transformer, the power supply allows for a minimal
electromagnetic field with no hum or mechanical noise. The power supply's
output side is filtered by an RC circuit to extract noise and hums caused by
your power service. 6000µf capacitors smooth out the positive and negative
half waves.
The phantom power is derived from a separate winding in the transformer,
a precise current regulator a clean phantom power of 48 volts. Our high
quality 0.1% / 6,81 kOhm resistors ensure the pristine quality of the phantom
power supply.
The 250 Volt power supply for the tube stage is filtered with 300 µF to
minimize hum.
The supply voltage can be set to 230 V/50 Hz or 115 V/60 Hz . Check your
country's power requirements for the appropriate setting. An AC power cord
is included to feed the IEC-spec, 3-prong connector. Transformer, AC cord
and IEC-receptacle are VDE, UL and CSA approved. The main fuse is rated at
315mA.
Chassis ground and AC ground can be physically disconnected by the
“Ground Lift” switch (GND LIFT). This helps to eliminate hums.