Page 1
LIMITED WARRANTY
1
O
This product is warranted to the original consumer purchaser to be free from
defects in materials and workmanship under normal installation, use and service for a
period of one (1) year from the date of purchase as shown on the purchaser’s receipt.
The obligation of Rolls Corporation under this warranty shall be limited to repair
or replacement (at our option), during the warranty period of any part which proves
defective in material or workmanship under normal installation, use and service, provided
the product is returned to Rolls Corporation, TRANSPORTA TION CHARGES PREPAID. Products returned to us or to an authorized Service Center must be accompanied by
a copy of the purchase receipt. In the absence of such purchase receipt, the warranty
period shall be one (1) year from the date of manufacture.
This warranty shall be invalid if the product is damaged as a result of defacement, misuse, abuse, neglect, accident, destruction or alteration of the serial number,
improper electrical voltages or currents, repair, alteration or maintenance by any person or
party other than our own service facility or an authorized Service Center, or any use
violative of instructions furnished by us.
This one-year warranty is in lieu of all expressed warranties, obligations or
liabilities. ANY IMPLIED WARRANTIES, OBLIGATIONS, OR LIABILITIES,
INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANT ABILITY AND FITNESS FOR A PARTICULAR PURPOSE, SHALL BE
LIMITED IN DURATION TO THE ONE YEAR DURATION OF THIS WRITTEN
LIMITED WARRANTY. Some states do not allow limitations on how long an implied
warranty lasts, so the above limitation may not apply to you.
IN NO EVENT SHALL WE BE LIABLE FOR ANY SPECIAL, INCIDENTAL
RP252
Compressor/Limiter/Gate
GAIN REDUCTION
8 1012182438
IO
7:1
9:1
:1
10 1 5 .5
mS
ATTACK RELEASE LEVEL
-12
-18
-24
-30
-40 +10
dB dB dB
THRESHOLD RATIO ATTACK RELEASE LEVEL
2.5
00
+10
Sec
-10 +20
dB dB
GAIN REDUCTION
124681012182438
7:1
4:1
-6
9:1
0
:1
10 1 5 .5
2:1
GATEACTIVE
2.5
mS
Sec
PWR
COMPRESSOR/LIMITER
+4
slowoff
-30
GATE THRESH GATE REL
GATE
fast
00
-10 +20
+10
GATEACTIVE
+4
slowoff fast
-30
GATE THRESH GATE REL
RP252
STEREO
-24
-30
1246
-12
-18
-40 +10
dB
THRESHOLD
RATI
7:
4:1
-6
0
2:1
OR CONSEQUENTIAL DAMAGES FOR BREACH OF THIS OR ANY OTHER
WARRANTY, EXPRESSED OR IMPLIED, WHATSOEVER. Some states do not allow
the exclusion or limitation of special, incidental or consequential damages so the above
limitation or exclusion may not apply to you. This warranty gives you specific legal
rights, and you may also have other rights which vary from state to state.
ROLLS CORPORATION
SAL T LAKE CITY, UT AH
11/01
OWNERS MANUAL
Page 2
TABLE OF CONTENTS
1
ROLLS CORPORATION
5968 South 350 West
Salt Lake City, UT 84107
1
RP252.SCH
E
Rev:
Sheet of
Rb
COMPRESSOR / LIMITER / GATE RP252
POWER
IN
OUT
OUTPUT TRIM
+V
+V
-V
-V
+V +V
+V +V
-V
-V
-V
2K
X 5
2K
X 5
2K
X 5
2K
X 5
+4/-10
R126
51
R249
10K
R257
10K
R264
10K
R157
10K
R149
10K
1 2
3
J2
XLR F PC
I
1
G
2
O
3
U17
7812
C3
1U
I
2
G
1
O
3
U18
7912
123
SW2A
DPDT
C4
47U
R263
10K
R147 22K
R235
1M
1U
CR3
1N4148
R248 18K
D15, D16, D17, D18, D19
D20, D21, D22, D23, D24
D25, D26, D27, D28, D29
D10, D11, D12, D13, D14
R150 R152
R151
R153
R154
R158
R159
R160
R161
R162
R250
R252
R251 R253
R254
R258
R260
R259
Q10
J113
D32
LDRR
R148
18K
D34
LDRR
CR2
1N751
R2
R7
1M
1
2
3
4
5
6
7
8
9
U13 BA6125
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
U15 BA6125
1
2
3
4
5
6
7
8
9
U16 BA6125
R256
1K
R255
4.7K
R163
10K
R155
4.7K
D5
LDSG
R102
10K
R101
10K
C101
27PF
D1
1N4001
D2
1N4001
D3
1N4001
D4
1N4001
C5
503
Q4
J113
R135
1M
R134
470
5
6
7
8
U11B
4560
123
SW3A
DPDT
456
SW3B
DPDT
456
SW2B
DPDT
R103
10K
R104
100K
R145
100K
C210
10U
1
2
3
SW4A
4PDT
456
SW4B
4PDT
789
SW5C
4PDT
R146
10K
R105
10K
R233
R231
470
R232
4.7K
R133
470
C110
10U
R132
4.7K
7
8
9
I/0 DPDT X4
SW4C
R119
4.7K
R131
470
R164
10K
5
6
7
8
U12B
4560
2
3
1
4
U1A
4560
R3
4.7K
C217 503
R118
22K
R247
22K
CR1
1N751
R1
4.7K
R261
R262
R156
1K
C1
2 2 0 0 U F 1 6 V
C2
2 2 0 0 U F 1 6 V
1 2
J6
XLR JACK M
1
2
3
J10
XLR JACK M
GATE CLOSED
RELEASE
R116
10K
4
3
8
1
11
5
7
2
U3A
LM13600
13
14
9
16
6
12
10
15
U3B
LM13600
2
3
1
4
4560
C104
503
R143
100
R123
47K
R120
10K
R112
10K
R125
22K
R115
220K
R110
100K
R111
22K
C105
10U
P9
P100K
P8
P100K
R122
10
C107
120PF
THRESHOLD
SIDE CHAIN
J7
PHONE 1/4
C111
1U
2
3
1
4
U2A
LM358
C112
27PF
R137 47K
R136
22K
500K
P14
R109
2K
R108
33K
R144 100K
R124
6.8K
C103
120PF
C108
1U
6
5
7
8
U4B
4560
R127
R130
47K
R128
4.7K
R129
4.7K
C109
27PF
R117
1M
R114
47K
1
1
2
2
3
3
Q3
J113
D6
1N4148
C106
503
Q1
2N3904
RATIO
OFFSET
C102
1U
5
6
7
8
U2B
LM358
Q2
2N3904
D31
LDRR
P100K
R106
1K
R121
220K
J1
PHONE 1/4
J8
PHONE 1/4
J5 PHONE 1/4
J9
PHONE 1/4
ATTACK
RELEASE
R138
10K
R139
10K
R140
10K
D7
1N4148
5
6
7
8
U5B
4560
P12
C10K
D8
1N4148
R141
10K
P13
100K
C114
10UF
P11
500K
-V
-V
-V
-V
+V
+V
+V
+V
+V
+V
+V
+V
+V
-V
-V
R5
50K TP
OUTPUT TRIM
-V
-V
+4/-10
R226
51
1 2
3
J4
XLR F PC
R202
10K
R201
10K
C201
120PF
R203
10K
R204
100K
R245
100K
1
2
3
SW5A
4PDT
456
SW5B
4PDT
R246
10K
R205
10K
R219
4.7K
2
3
1
4
U6A
4560
R218
22K
GATE CLOSED
RELEASE
R216
4
3
8
1
11
5
7
2
U8A
LM13600
13
14
9
16
6
12
10
15
U8B
LM13600
2
3
1
4
4560
C204
503
R243
100
R223
47K
R220
10K
R212
10K
R207
100K
R225
22K
R215
220K
R210
100K
R211
22K
C205
10U
P2
P100K
P1
P100K
R222
10
C207
120PF
THRESHOLD
J11
PHONE 1/4
C211
1U
2
3
1
4
U7A
LM358
C212
27PF
R237
47K
R236
22K
P7 500K
R209
2K
R208
33K
R244 100K
R224
6.8K
C203
120PF
C208
1U
6
5
7
8
U9B
4560
R227
18K
R230
47K
R228
4.7K
R229
4.7K
C209
27PF
R217
1M
R214
47K
1
1
2
2
3
3
Q9
J113
D9
1N4148
C206
503
Q7
2N3904
RATIO
OFFSET
C202
1U
5
6
7
8
U7B
LM358
Q8
2N3904
LDRR
P3
P100K
R206
1K
R221
220K
J3
PHONE 1/4
J12
PHONE 1/4
ATTACK
RELEASE
R238
10K
R239
10K
R240
10K
D35
1N4148
P5
C10K
D36
1N4148
R241
10K
P6
100K
C214
10UF
P4
500K
-V
-V
-V
-V
+V
+V
+V
+V
+V
+V
-V
-V
R6
50K TP
C117
.047
1
2
3
SW1A
DPDT
456
SW1B
DPDT
STEREO/MONO
D33
LDRG
R4
4.7K
-V
+V
E1E3E2
+V
-V
2
3
1
4
4560
3
2
1
4
U11A
4560
5
6
7
8
U10B
4560
2
3
1
4
U10A
4560
3
2
1
4
U12A
4560
+V
7
8
U1B
7
8
U6B
+V
+V
-V
-V
C8
.001
C9
.001
C10
.001
.001
R8
4.7K
R9
4.7K
C6
503
C7
503
C12 470PF
C13
470PF
D 3 8
1 N 4 1 4 8
D 3 7
1 N 4 1 4 8
D 4 0
1 N 7 5 1 A
D 3 9
1 N 7 5 1 A
R107
100K
U5A
3
R234
470
BYPASS
6
5
4560
6
5
4560
Size:
U9A
C11
U14 BA6125
Document Number:
Date: 14 October 2001
SCHEMATIC
Table of Contents 1
Inspection 1
Specifications 1
Introduction 2
Understanding Compression 2
Gating 2
Description 3
Front P anel 3
Rear Panel 4
Operation 4-5
Schematic 6
Warranty Back Cover
INSPECTION
1. Unpac k and Inspect the RP252 pac kage
Your RP252 was carefully packed at the factory in a protective carton.
Nonetheless, be sure to examine the unit and the carton for any signs of
damage that may hav e occurred during shipping. If obvious physical
damage is noticed, contact the carrier immediately to make a damage
claim. We suggest saving the shipping carton and packing materials for
safely transporting the unit in the future.
2. Please complete the Warranty Registration Card and return it to the
factory.
SPECIFICATIONS
Input Impedance: 10k9 balanced
Max Input Level: +21 dBu
THD: .05% typical
Threshold range: -40dBu to +10dBu
Attack Time: 1 - 10ms.
Release Time: 0.5 - 5 Sec.
Compression Ratio: 2:1 - infinity:1
Gate Threshold: -30 to +4 dB, and Off.
Output Gain: -10 - +20dB
Dimensions: 1.75" x 6" x 19"
1 6
(44mm x 152mm 483mm)
Page 3
OPERATION CONT
INTRODUCTION
Raising the Signal Out of a Mix
Since reducing dynamic range can increase the aver age signal le v el and meter
readings, a single track can be brought up out of a mix by boosting its level slightly
and applying compression. Set the Threshold for 4 dB to 6 dB of compression.
Preventing Sound System Ov erload (Limiting)
Applications where an abolute maximum signal lev el must be set to a void distortion or speaker damage, set the RP252 f or Limiting. Limiting has been defined as
a signal-to-compression ratio of 10:1 or more. Start with the Ratio at infinity:1, use
a fast Attack and set the Threshold at 15 dB of compression or just a few dB
below the clipping point of the sound system. At low le vels the RP252 won’t do
anything, but at higher lev els the peaks will be limited to the Threshold point.
Often, it is recommended the compressor/limiter be inserted just before the power
amp, some systems e v en ha v e a separ ate compressor/limiter on each output of
the crossover.
Thank you for choosing the R OLLS RP252 Compressor/Limiter/Gate. We recommend you take a moment and read through this manual as it provides information
that will assist you in using your unit to it’ s fullest potential.
The RP252 provides clear sonic quality and performance for the working musician, DJ, studio operator , or an yone needing a friendly Compressor/ Limiter/Gate .
The RP252 incorporates “soft-knee” compression and a 100 dB log av er aging
detector for amazing accuracy and smooth perf ormance. The input connectors on
the rear are designed to be used with -10 dB to +4 dB signal levels .
UNDERST ANDING COMPRESSION
The primary purpose of a compressor is to reduce and control the dynamic range
of a program; from gentle narro wing of overall levels to limiting of peaks , to
squashing all dynamics. Control is the main idea.
Another major use for compressors is to add punch to sloppy sounds. A compressor can do this by making the lev el of an instrument or a sound more consistent,
or by reducing the volume of the more sustained sections of a note, which comparatively accentuates the leading edge (Attack).
Sustain of instruments, especially guitars and bass can be achieved b y raising the
volume of low-le vel tr ailing edges of a note , which giv es solid presence to the
instrument. It also makes the note-b y-note v olume more even. All this is done b y
changing the gain in response to the signal. When the input is low in lev el, the
compressor gain remains fixed, usually at 0 dB (unity gain) or greater. When the
input increases above the threshold set by the compressor, the gain begins to
decrease (i.e., the amount of gain reduction increases). F or v ery large inputs, the
gain can decrease considerably, Therefore, as signals get larger , the gain reduction will increase, depending where the Threshold, Ratio and Output Level are
set.
GATING
Gating is used to cut noise or “hiss” when there is no signal, or when the signal is
below a certain threshold. Sometimes, such as with drums, the gate is used to
stop all sound except when the drum is play ed, to remov e bac kg round noise.
25
Page 4
DESCRIPTION
DESCRIPTION CONT .
FRONT PANEL
NOTE: Descriptions are identical for both Channels One and Two
GAIN REDUCTION
1 2 4 6 81012182438
-12
4:1
-18
-6
0
-24
-30
-40 +10
2:1
dB dB dB
THRESHOLD RATIO ATTACK RELEASE LEVEL
7:1
9:1
:1
10 1 5 .5
mS
2.5
00
Sec
-10 +20
+10
GATEACTIVE
+4
slowoff
-30
GATE THRESH GATE REL
STEREO
fast
GAIN REDUCTION
124681012182438
RATIO
7:1
9:1
10 1 5 .5
:1
mS
ATTACK RELEASE LEVEL
2.5
00
Sec
-10 +20
-12
4:1
-18
-6
0
-24
-30
-40 +10
2:1
dB dB dB
THRESHOLD
+10
GATEACTIVE
+4
slowoff
-30
GATE THRESH GATE REL
PWR
COMPRESSOR/LIMITER
GATE
fast
RP252
THRESHOLD: Sets the le v el at which the RP252 becomes activ e . When the
signal level is belo w the threshold point, the signal is unprocessed. When the
signal level is abov e the threshold point, there ma y be compression/limiting.
RATIO: This sets the ratio of input signal to signal compression. Called ‘signal-tocompression ratio, at 1:1 the signal is left unprocessed and at infinity:1, no matter
how much the input increases, the output will not be abov e the threshold - this is
called limiting.
ATTACK: Adjusts ho w fast the control circuits respond to the dynamics of the
input. If this is set longer, it will take more time for gain reduction to occur, so
rapidly rising inputs will go through for a short period of time.
RELEASE: Adjusts how long before the control circuits return to a steady state. A
short release time can make sound be choppy and gated. A long release time can
make music seem to rise and fall as a wave. It is recommended to start with a
long Release time, then shorten it if necessary.
OUTPUT LEVEL: Sets the output le v el to help compensate f or compression
losses. If the Threshold is set low , more output le vel may be needed because gain
reduction starts at a low level.
GATE THRESHOLD: Included in the RP252 is a noise gate circuit which is
accessed with the two gate controls. The Gate Threshold sets the point at which
the gate “opens” to let the sound through. Below this level, the entire signal is shut
off. When the GATE LED is off there is enough level to operate the gate.
GATE RELEASE: As bef ore, this adjusts ho w long until the gate closes or stops
sound after the signal has fallen below the threshold.
ACTIVE SWITCH: Pressing this switch inward activates the compressor .
STEREO SWITCH: This switch joins the control circuits of the two channels so
they operate together . When processing a stereo signal, this helps maintain a
more natural sound because both sides are processed exactly the same.
GAIN REDUCTION LEDs: These 10 LEDs display, in dB, how much the signal is
being compressed (i.e., how much gain reduction).
GATE LED: When this is lit, no signal passes through the processing circuits and
the sound is muted.
REAR PANEL
NOTE: Descriptions are identical for both Channels One and Two
120 VAC
50/60 Hz 15 VA
MADE IN U.S.A.
MODEL RP252
SERIAL NUMBER
252-
RISQUE DE CHOC - NE PAS ENLEVER
C US
CHANNEL 2
SIDE CHAIN
OUTPUT
INPUTOUTPUT
INPUT
INST
LINE
CHANNEL 1
SIDE CHAIN
INPUTOUTPUT
OUTPUT
WARNING:
INPUT
INST
LINE
To reduce the
risk of electric shock or fire,
do not expose this device to
:
rain or moisture.
CAUTION:
To reduce the risk
of electric shock do not remove
lid. No user serviceable parts
inside. Refer servicing to
qualified service personnel.
INPUT: Use mono (or TRS) 1/4" phone connectors or balanced XLR inputs from
your line-lev el audio source .
OUTPUT: Use mono (or TRS) 1/4" phone connectors or balanced XLR to connect
to the line inputs on the next device (i.e ., mix er, recording device, amplifier, etc.)
SIDE CHAIN: The side chain ins/outs are 1/4" unbalanced jacks used for controlling the gain reduction circuits with an external signal. This is for special effects
such as “ducking”.
INST/LINE SWITCH: This switch changes the RP252 dynamic range by 20 dB . In
for instrument level, out for line level signals.
OPERATION
Smoothing Out Electric Bass
Bass lines often are inconsistent in level and lac k the sustain needed to giv e a
solid bottom end. Set the Threshold so that peaks cause 10 dB to 12 dB of
compression. Use more f or increased sustain and for more percussive attacks on
the trainsients.
Fattening Kic k Drums and Compressing Other Drum Sounds
Weak, flabby kic k drums often hav e too m uch boom and not enough slap . Tighen
them up by increasing the Attack time and setting the threshold for 15 dB of
compression on the peak of the kick. Because the RP252 tak es time to react, this
will emphasize the slap at the beginning of the note and reduce the boominess of
its body. The RP252 also works well for tightening snare drums and tom toms and
can be used with drum machines to effectively alter the character of an y electronic drum sound.
Variations in Mic Levels
In musical applications, paging systems, churches, speaking e v ents, etc., as the
distance between the microphone and the speaker or the vocalist changes , signal
levels change . To keep the level near constant, set the threshold and ratio so an
average of 6 - 8 dB of compression is estab lished.
3 4
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