Rane FPL 44 User Manual

OPERATING/SERVICE MANUAL

QUICK START

In deference to the ecological movement, Rane has made a commitment to keep its manuals
short and to the point. After all, we’re in the electronics business, not the tree industry. In
deference to your patience, we include this hurry-up section.

Inputs on the FPL 44 are 1/4" TRS balanced/unbalanced. Outputs are balanced 3-pin (XLR).
Positive appears on the tip of the input and pin 2 on the output; negative is the ring of the input
and pin 3 on the output. Signal ground is either sleeve or pin 1.

Front panel settings include four THRESHOLD controls, four BYPASS switches and four
SLAVE switches. The THRESHOLD controls set the level at which output limiting occurs.
BYPASS directly connects the input to the output. The AUTO-SLAVE switch connects the VCA in
the channel to the “slave” bus. In this position all channels in AUTO-SLAVE limit by the same
amount when any one channel exceeds its threshold level. The channels may be. set at different
thresholds to suit the requirements of each situation. If one channel is overdriven by, say, 10 dB,
its gain and the gain of all others in the slave mode reduces by the same 10 dB.

NEVER CONNECT A NYTHING EXCEPT AN APPROVED RANE AC POWER SUPPLY
TO THE THING THAT LOOKS LIKE A RED TELEPHONE JACK ON THE REAR OF
THE FPL 44. This is an AC power input and requires special attention if you do not have a
power supply EXACTLY like the one originally supplied with your unit. A Rane Model FRS 8 or
RAP 10 power supply is acceptable as well. Please see the full explanation of power supply
requirements elsewhere in this manual.

FPL 44

SYSTEM CONNECTION

When connecting the FPL 44 to other components of a sound system for the first time, LEAVE
THE POWER SUPPLY FOR LAST. This allows for any mistakes to be identified by visual inspec­tion and corrected before power is applied and it becomes too late.

INPUTS on the FPL 44 are balanced. The hardware provided for input connectors are 1/4" tip­ring-sleeve jacks. The tip of the jack is the positive input, the ring is the negative input and the
sleeve is signal ground. Unbalanced inputs may either ground the ring or leave it open while driv­ing the tip with the unbalanced signal. The FPL 44’s input circuitry is of the instrumentation vari­ety, eliminating concern over open negative inputs, while ensuring equal differential and
common-mode impedances.

OUTPUTS. The outputs on this device are balanced as well. They differ from the inputs only by
way of their hardware implementation. The Flex philosophy dictates using 1/4" connectors for sig­nal flow inside of a rack. Lines likely to exit a rack are of the 3-pin variety. If you read the “Quick
Start” section above, you already know that pin 2 of the output connectors is positive, pin 3 is nega­tive and pin 1 is signal ground.

POWERING UP. In the opening paragraph it was stated that a good visual inspection often elimi­nates disasters before applying power. It cannot be overstated how important it is to use the correct
power supply with this and all Flex modules. The Rane RS 1 single AC power supply (included
with each module) as well as the Rane FRS 8 and RAP 10 power supplies are the only power sup­plies certain to work properly with this limiter. If another power supply is to he considered, it must
be an AC supply. It must have an 18 to 24 volt center-tapped output and be wired to a 6-pin mod
connector in accordance with the requirements of the Rane standard.

FRONT PANEL DESCRIPTION

1. CHANNEL BYPASS SWITCH. This switch provides a passive bypass of each chan-

nel of the FPL 44. When pressed in, it directly connects the positive, negative and signal
ground inputs to the positive, negative and signal ground outputs of the channel. It is pro­vided to allow easy A/B comparison of limiter activity. It also serves to pass the audio sig­nal around the active circuitry of the limiter in the event of power failure.

2. BYPASS INDICATOR. This red LED illuminates to advise the operator of a bypass

condition, i.e., BYPASS switch pressed in.

3. LIMIT THRESHOLD CONTROL & INDICATOR. The calibrations (in dBu,

0 dBu = 0.776 Vrms) around this knob indicate the point at which the output limits. All lev-

els higher than this setting are reduced to this preset amplitude. The indicator illuminates

when the preset threshold is exceeded.

4. AUTO-SLAVE SWITCH. In the INDEPENDENT position (“down” in the vertical

orientation,
In the AUTO-SLAVE position (“up” in the vertical orientation, “left” in the horizontal),
each channel limits the same amount that any other channel in the slave mode does. If only
one channel of the possible four is set to this mode, it operates independently. If two or
more are set to AUTO-SLAVE, all slaved channels will attenuate the same amount when
any one exceeds its THRESHOLD.

“right” when horizontally mounted) each limiter channel operates separately.

5. POWER INDICATOR. This yellow LED illuminates when an appropriate power sup

ply is connected to the FPL 44 and is, itself, connected to an appropriate power source.
For the definition of “appropriate power supply,” please refer to the front page of this man­ual. It doesn’t really make a lot of sense to beat this issue to death alter having done so
twice on the first page.