Rolls RP252 User manual

Brand: Rolls

Model: RP252

Category: Supplementary music equipment

Type: User manual

Rolls RP252 is a versatile audio processor that combines a compressor, limiter, and gate in a single unit. It features a "soft-knee" compression algorithm for smooth and natural-sounding results, and a 100 dB log averaging detector for accurate level control. The RP252 can be used for a wide range of applications, including:

Compression: Reducing the dynamic range of a signal to make it more consistent and controlled. This can be useful for evening out the volume of a vocal or instrument, or for adding punch to a weak signal.
Limiting: Preventing a signal from exceeding a certain level. This can be useful for protecting speakers from damage, or for ensuring that a signal does not overload a recording device.

Compression: Reducing the dynamic range of a signal to make it more consistent and controlled. This can be useful for evening out the volume of a vocal or instrument, or for adding punch to a weak signal.
Limiting: Preventing a signal from exceeding a certain level. This can be useful for protecting speakers from damage, or for ensuring that a signal does not overload a recording device.

RP252

Compressor/Limiter/Gate

OWNERS MANUAL

ROLLS CORPORATION

SALT LAKE CITY, UTAH

11/01

LIMITED WARRANTY

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, TRANSPORTATION CHARGES PRE-

PAID. 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 deface-

ment, 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 MER-

CHANTABILITY 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

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.

STEREO

-40 +10

-30

-24

-12

-6

2:1

9:1

7:1

4:1

10 1 5 .5

2.5

-10 +20

-30

slowoff fast

THRESHOLD RATIO ATTACK RELEASE LEVEL

GATE THRESH GATE REL

GATEACTIVE

GAIN REDUCTION

124681012182438

1246

-18

dB dB dB

Sec

-40 +10

-30

-24

-12

-6

2:1

4:1

THRESHOLD

RATI

-18

+10

PWR

COMPRESSOR/LIMITER

GATE

RP252

GATEACTIVE

GAIN REDUCTION

8 1012182438

9:1

7:1

10 1 5 .5

2.5

-10 +20

-30

slowoff

fast

ATTACK RELEASE LEVEL

GATE THRESH GATE REL

dB dB

Sec

+10

TABLE OF CONTENTS

Table of Contents 1

Inspection 1

Specifications 1

Introduction 2

Understanding Compression 2

Gating 2

Description 3

Front Panel 3

Rear Panel 4

Operation 4-5

Schematic 6

Warranty Back Cover

INSPECTION

1. Unpack and Inspect the RP252 package

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 have 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"

(44mm x 152mm 483mm)

1 6

SCHEMATIC

ROLLS CORPORATION

5968 South 350 West

Salt Lake City, UT 84107

RP252.SCH

Rev:

Sheet of

COMPRESSOR / LIMITER / GATE RP252

POWER

OUT

OUTPUT TRIM

-V

+V +V

-V

X 5

+4/-10

R126

R249

10K

R257

10K

R264

10K

R157

10K

R149

10K

1 2

XLR F PC

U17

7812

U18

7912

SW2A

DPDT

47U

R263

10K

R147 22K

R235

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

U13 BA6125

U15 BA6125

U16 BA6125

R256

R255

4.7K

R163

10K

R155

4.7K

LDSG

R102

10K

R101

10K

C101

27PF

1N4001

503

J113

R135

R134

470

U11B

4560

SW3A

DPDT

SW3B

DPDT

SW2B

DPDT

R103

10K

R104

100K

R145

100K

C210

10U

SW4A

4PDT

SW4B

4PDT

SW5C

4PDT

R146

10K

R105

10K

R233

R231

470

R232

4.7K

R133

470

C110

10U

R132

4.7K

I/0 DPDT X4

SW4C

R119

4.7K

R131

470

R164

10K

U12B

4560

U1A

4560

4.7K

C217 503

R118

22K

R247

22K

CR1

1N751

4.7K

R261

R262

R156

2 2 0 0 U F 1 6 V

1 2

XLR JACK M

J10

XLR JACK M

GATE CLOSED

RELEASE

R116

10K

U3A

LM13600

U3B

LM13600

4560

C104

503

R143

100

R123

47K

R120

10K

R112

10K

R125

22K

R115

220K

R110

100K

R111

22K

C105

10U

P100K

R122

C107

120PF

THRESHOLD

SIDE CHAIN

PHONE 1/4

C111

U2A

LM358

C112

27PF

R137 47K

R136

22K

500K

P14

R109

R108

33K

R144 100K

R124

6.8K

C103

120PF

C108

U4B

4560

R127

R130

47K

R128

4.7K

R129

4.7K

C109

27PF

R117

R114

47K

J113

1N4148

C106

503

2N3904

RATIO

OFFSET

C102

U2B

LM358

2N3904

D31

LDRR

P100K

R106

R121

220K

PHONE 1/4

J5 PHONE 1/4

PHONE 1/4

ATTACK

RELEASE

R138

10K

R139

10K

R140

10K

1N4148

U5B

4560

P12

C10K

1N4148

R141

10K

P13

100K

C114

10UF

P11

500K

-V

50K TP

OUTPUT TRIM

-V

+4/-10

R226

1 2

XLR F PC

R202

10K

R201

10K

C201

120PF

R203

10K

R204

100K

R245

100K

SW5A

4PDT

SW5B

4PDT

R246

10K

R205

10K

R219

4.7K

U6A

4560

R218

22K

GATE CLOSED

RELEASE

R216

U8A

LM13600

U8B

LM13600

4560

C204

503

R243

100

R223

47K

R220

10K

R212

10K

R207

100K

R225

22K

R215

220K

R210

100K

R211

22K

C205

10U

P100K

R222

C207

120PF

THRESHOLD

J11

PHONE 1/4

C211

U7A

LM358

C212

27PF

R237

47K

R236

22K

P7 500K

R209

R208

33K

R244 100K

R224

6.8K

C203

120PF

C208

U9B

4560

R227

18K

R230

47K

R228

4.7K

R229

4.7K

C209

27PF

R217

R214

47K

J113

1N4148

C206

503

2N3904

RATIO

OFFSET

C202

U7B

LM358

2N3904

LDRR

P100K

R206

R221

220K

PHONE 1/4

J12

PHONE 1/4

ATTACK

RELEASE

R238

10K

R239

10K

R240

10K

D35

1N4148

C10K

D36

1N4148

R241

10K

100K

C214

10UF

500K

-V

50K TP

C117

.047

SW1A

DPDT

SW1B

DPDT

STEREO/MONO

D33

LDRG

4.7K

-V

4560

U11A

4560

U10B

4560

U10A

4560

U12A

4560

U1B

U6B

-V

.001

C10

.001

4.7K

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

R234

470

BYPASS

4560

Size:

U9A

C11

U14 BA6125

Document Number:

Date: 14 October 2001

INTRODUCTION

Thank you for choosing the ROLLS RP252 Compressor/Limiter/Gate. We recom-

mend 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 musi-

cian, DJ, studio operator, or anyone needing a friendly Compressor/ Limiter/Gate.

The RP252 incorporates “soft-knee” compression and a 100 dB log averaging

detector for amazing accuracy and smooth performance. The input connectors on

the rear are designed to be used with -10 dB to +4 dB signal levels.

UNDERSTANDING COMPRESSION

The primary purpose of a compressor is to reduce and control the dynamic range

of a program; from gentle narrowing 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 compres-

sor can do this by making the level of an instrument or a sound more consistent,

or by reducing the volume of the more sustained sections of a note, which com-

paratively accentuates the leading edge (Attack).

Sustain of instruments, especially guitars and bass can be achieved by raising the

volume of low-level trailing edges of a note, which gives solid presence to the

instrument. It also makes the note-by-note volume more even. All this is done by

changing the gain in response to the signal. When the input is low in level, 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). For very large inputs, the

gain can decrease considerably, Therefore, as signals get larger, the gain reduc-

tion 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 played, to remove background noise.

OPERATION CONT

Raising the Signal Out of a Mix

Since reducing dynamic range can increase the average signal level 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 Overload (Limiting)

Applications where an abolute maximum signal level must be set to avoid distor-

tion or speaker damage, set the RP252 for 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 levels the RP252 won’t do

anything, but at higher levels 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 even have a separate compressor/limiter on each output of

the crossover.

DESCRIPTION

FRONT PANEL

NOTE: Descriptions are identical for both Channels One and Two

STEREO

PWR

COMPRESSOR/LIMITER

GATE

RP252

-40 +10

-30

-24

-12

-6

2:1

9:1

7:1

4:1

10 1 5 .5

2.5

-10 +20

-30

slowoff

fast

THRESHOLD RATIO ATTACK RELEASE LEVEL

GATE THRESH GATE REL

GATEACTIVE

GAIN REDUCTION

1 2 4 6 8 1012182438

GATEACTIVE

GAIN REDUCTION

124681012182438

-18

dB dB dB

Sec

-40 +10

-30

-24

-12

-6

2:1

9:1

7:1

4:1

10 1 5 .5

2.5

-10 +20

-30

slowoff

fast

THRESHOLD

RATIO

ATTACK RELEASE LEVEL

GATE THRESH GATE REL

-18

dB dB dB

Sec

+10

THRESHOLD: Sets the level at which the RP252 becomes active. When the

signal level is below the threshold point, the signal is unprocessed. When the

signal level is above the threshold point, there may be compression/limiting.

RATIO: This sets the ratio of input signal to signal compression. Called ‘signal-to-

compression 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 above the threshold - this is

called limiting.

ATTACK: Adjusts how 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 level to help compensate for compression

losses. If the Threshold is set low, more output level 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 before, this adjusts how 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.

DESCRIPTION CONT.

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-

OUTPUT

CHANNEL 2

SIDE CHAIN

INPUT

INPUTOUTPUT

RISQUE DE CHOC - NE PAS ENLEVER

OUTPUT

CHANNEL 1

SIDE CHAIN

INPUT

INST

LINE

INST

LINE

INPUTOUTPUT

C US

WARNING:

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-level 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., mixer, recording device, amplifier, etc.)

SIDE CHAIN: The side chain ins/outs are 1/4" unbalanced jacks used for control-

ling 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 lack the sustain needed to give a

solid bottom end. Set the Threshold so that peaks cause 10 dB to 12 dB of

compression. Use more for increased sustain and for more percussive attacks on

the trainsients.

Fattening Kick Drums and Compressing Other Drum Sounds

Weak, flabby kick drums often have too much 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 takes 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 any elec-

tronic drum sound.

Variations in Mic Levels

In musical applications, paging systems, churches, speaking events, 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 established.

3 4

Rolls RP252 User manual

Brand: Rolls

Model: RP252

Category: Supplementary music equipment

Type: User manual

Compression: Reducing the dynamic range of a signal to make it more consistent and controlled. This can be useful for evening out the volume of a vocal or instrument, or for adding punch to a weak signal.
Limiting: Preventing a signal from exceeding a certain level. This can be useful for protecting speakers from damage, or for ensuring that a signal does not overload a recording device.

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Rolls RP252 User manual

Rolls RP252 User manual

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