OPERATING INSTRUCTIONS
The internal PRE/POST switches allow you to determine
whether an individual output is to be routed through the
MASTER level control. If all eight switches are set to the
PRE position, the MASTER level control is defeated and
has no effect over any of the outputs. It is for this reason
that all FPS 28s are shipped from the factory with all
switches in the POST position. This helps eliminate ques-
tions about possible defective controls. The normal use of
the FPS 28 would be in a situation where the MASTER
level controls adjust the level of all outputs together
without disturbing the relative levels between the outputs.
There are eight separate switches so that some zones or
splits can be adjusted with the MASTERS and some not.
For optimum noise performance from microphone in-
puts, it is always advisable to run as much gain as possible
in the first stage of amplification. For this reason, set the
gain control so that at the highest expected sound levels at
the microphone the overload LEDs occasionally blink, Ob-
viously, trading constantly lit overload LEDs (and the ensu-
ing distortion) for lower noise is not a great idea. Make
sure the selector switch on the rear is in the OUT position
for microphone use. In the line level configuration, unity
gain is probably a good place to start. This may be found at
approximately “4” on the GAIN control.
POWER SUPPLY.
As noted elsewhere in this manual,
NEVER USE A POWER SUPPLY WITH YOUR FPS 28
This module serves two similar yet different functions. In
the “stereo” mode, it will split two inputs into four pairs of
outputs. The two inputs may be set at different levels if
necessary via the concentric MASTER level controls. All
eight outputs (4 pairs) may be set as necessary through the
use of the four sets of concentric OUTPUT level controls.
In the “mono” mode, one input may drive all eight outputs,
again with separate MASTER and OUTPUT level con-
trols.
OTHER THAN THE ONE SUPPLIED FROM THE FAC-
TORY OR AN EXACT REPLACEMENT OBTAINED
FROM RANE CORPORATION. This unit’s power supply
input is designed for an AC supply, delivering 18-24 volts,
from a center-tapped transformer capable of supplying at
least the current demanded by this product. Using any
other type of supply may damage the module and void the
warranty (which at two years parts and labor is worth
safeguarding, don’t you think?).
CHASSIS GROUNDING
Rane Flex Series modules are supplied with either a
rear, or a bottom-side mounted ground-lift switch. The
unit is shipped with this switch in the “grounded” posi-
tion, tying circuit ground to chassis ground. If after
hooking up your system it exhibits excessive hum or
buzzing, there is an incompatibility in the grounding
configuration between units somewhere. Your mission,
should you accept it, is to discover how your particular
system wants to be grounded. Here are some things to
try:
1. Try combinations of lifting grounds on units that are
supplied with ground lift switches or links.
2. If your equipment is in a rack, verify that all chassis
are tied to a good earth ground, either through the line
cord grounding pin or the rack screws to another
grounded chassis.
3. Units with outboard power supplies do not ground
the chassis through the line cord. Make sure that these
units are grounded either to another chassis which is
earth grounded, or directly to the grounding screw on
an AC outlet cover by means of a wire connected to a
screw on the chassis with a star washer to guarantee
proper contact.
Please refer to Rane Note 110 (supplied with your
unit and available on request at no charge if you lost
your first one) for further information on system
grounding.
IMPORTANT NOTE
Copyright 1990, Rane Corporation 10802 47th Ave. W. Mukilteo, WA 98275 (425)355-6000
520-114 390
