Operating instructions – Rane FPM 42 User Manual

Page 4

OPERATING INSTRUCTIONS

This unit serves two similar yet different functions. It may

be operated as a stand-alone 4-input to 2 or 4-output
mixer, or it may be used in conjunction with other Flex
mixer modules to create a larger system. For instance, via
the Flex bus system, the FPM 42 may be connected to
other like units to accommodate an infinite number of in-
puts, which may be mixed to as many as 4 outputs. It may
also be used in conjunction with FMI 14s when the
equalization features of those units are required on one or
more inputs. The module may also be used with the FMM
42 Master Module which features auxiliary bus outputs,
which also may be mixed with the A and B main outputs
for effects mixing. The possibilities are staggering and we
shall attempt to introduce them, so you may fully under-
stand the range of talent provided by the FPM 42.

STAND-ALONE. As an independent 4-input to 2 or 4-

output mixer, the FPM 42 is a reasonably straightforward
device. The 4 inputs are mixed to either, or both, of two
main buses, A and B, as well as to both auxiliary buses via
the Aux send control on the front of the unit. The A and B
input LEVEL controls determine the amount of input sig-
nal to be applied to each of the main buses. The A and B
MASTER level controls at the end of the signal path set
the levels for the final output at the A and B MASTER
OUTPUT jacks on the rear of the unit. The Aux inputs up-

pear ONLY on the bus unless you choose to change the op-

tional internal jumpers to program the second l/4” output to
be unbalanced Aux A/B. The AUX send control on each

input places an equal amount of program on each of the
AUX A/B OUTPUTS. The source for the Aux is deter-
mined by setting the internal assign switches to be either
pre- or post- the input LEVEL controls. It is important to

note that this is a single control for both outputs.

MULTIPLE MODULES. As previously mentioned, the

FPM 42 may be used in conjunction with other Flex mixer
modules to create a large system. This is accomplished
through the use of the BUS IN and BUS OUT jacks on the
rear of the unit. Each mixer module in the system places
its Master and Aux mixes on the respective buses internal-
ly and provides this information to the BUS OUT jack.
When these signals are connected to the BUS IN jack on a
succeeding unit, they combine in the next unit with any
local program material generated in that unit and the sum

of the two will be available at the second unit’s BUS OUT

jack.

Each Flex mixer module sums all bus information in such

a way that the Flex BUS OUT is a low impedance line.
This differs rather dramatically from the way most mixers
operate. Normally this line would be very sensitive to noise
and would be impossible to bring out of the mixer, even in
a well shielded cable. This is not a problem with the Flex
Bus System and this allows as many modules to be com-
bined on one bus as could ever be necessary.

For further system connection possibilities, please refer

to the Flex Users Guide.

POWER SUPPLY. As noted elsewhere in this manual,

NEVER USE A POWER SUPPLY WITH YOUR FPM 42
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 unit and void the war-
ranty (which at two years parts and labor is worth
safeguarding, don’t you think?).

IMPORTANT NOTE

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”
position, tying circuit ground to chassis ground. If
after hooking up your system it exhibits excessive hum
or buzzing, there is an incompatibility in the ground-
ing configuration between units somewhere. Your mis-
sion, 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 chas-

sis 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 con-
nected 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.

520-167 490