Page 1
Redbox
User Handbook No 2
Matching Converters, Distribution
Amplifiers & Headphone Amplifiers
RB-UL1 Single stereo unbalanced to balanced converter
RB-UL2 Dual stereo unbalanced to balanced converter
RB-UL4 Quad stereo unbalanced to balanced converter
RB-LU4 Quad stereo balanced to unbalanced converter
RB-BL2 Single stereo bi-directional matching converter
RB-BL4 Dual stereo bi-directional matching converter
RB-PA2 Dual stereo RIAA phono amplifier
RB-LI2 Stereo line isolation unit
RB-PLI6 6 way mono passive line isolation unit
RB-DA6 6 way stereo distribution amplifier
RB-DA6G 6 way stereo distribution amplifier with output
gain control
RB-DA4x5 4 input, 4 x 5 output distribution amplifier/mixer
RB-DDA6A 6 way stereo AES/EBU digital distribution amplifier
RB-DDA6S 6 way stereo S/PDIF digital distribution amplifier
RB-DDA6W 6 way word clock digital distribution amplifier
RB-HD1 Stereo headphone amplifier
RB-HD2 Dual stereo headphone amplifier
RB-HD6 6 way stereo headphone distribution amplifier
RB-DHD6 Digital 6 way stereo headphone distribution amplifier
Page 2
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Redbox User Handbook No 2
Revision 2.02 June, 2007
©Sonifex Ltd, 2000-7
All Rights Reserved
Sonifex Ltd, 61, Station Road, Irthlingborough,
Northants, NN9 5QE, England.
Tel : +44 (0)1933 650 700
Fax : +44 (0)1933 650 726
Email : [email protected] or [email protected]
Web : http://www.sonifex.co.uk
Information in this document is subject to change without notice and does not represent
a commitment on the part of Sonifex Ltd. Sonifex Ltd shall not be liable for any loss or
damage whatsoever arising form the use of information or any error contained in this
manual.
No part of this manual may be reproduced or transmitted in any form or by any means,
electronic or mechanical, including photocopying, recording, or information storage and
retrieval systems, for any purpose other than the purchaser’s personal use, without the
express written permission of Sonifex Ltd.
Unless otherwise noted, all names of companies, products and persons contained herein are
part of a completely fictitious adaptation and are designed solely to document the use of
Sonifex products.
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Redbox User Handbook No 2
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CONTENTS
Warranty i
Warranty and Liability - important the purchaser is advised to read this clause i
Unpacking the Redbox ii
Returning the Warranty Card iii
Safety Information iii
Safety of Mains Operated Equipment iii
Voltage Setting Checks iii
Fuse Rating iii
Power Cable and Connection iv
Ordering the Correct Mains Lead iv
Installation Information iv
Atmosphere iv
Electromagnetic Radiation iv
Fitting Redboxes iv
WEEE & RoHS Directives - Sonifex Statement vi
MATCHING CONVERTERS
1 RB-UL1 Single, RB-UL2 Dual & RB-UL4 Quad Stereo Unbalanced
To Balanced Converters 1
Introduction 1
System Block Diagram 1
Rear Panel Connections and Operation 2
RCA Phono Inputs (Left and Right) 3
Outputs (Left and Right) 3
Output Level Adjustment 3
Technical Specifications 4
CONTENTS
2 RB-LU4 Quad Stereo Balanced To Unbalanced Converter 5
Introduction 5
System Block Diagram 6
Rear Panel Connections and Operation 7
Inputs 1-4 (Left and Right) 7
RCA Phono Outputs 1-4 (Left and Right) 7
Output Level Adjustment 7
Technical Specifications 8
3 RB-BL2 Single & RB-BL4 Dual Bi-Directional Matching Converter 9
Introduction 9
System Block Diagram 10
Rear Panel Connections and Operation 10
Balanced to Unbalanced Connections 11
Inputs 1 (& 3) (Left & Right) 11
Output Level Adjustment 11
Unbalanced to Balanced Connections 11
RCA Phono Inputs 2 (& 4) (Left & Right) 11
Technical Specifications 12
4 RB-PA2 Dual Stereo RIAA Phono Amplifier 13
Introduction 13
System Block Diagram 13
Rear Panel Connections and Operation 14
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Redbox User Handbook No 2
CONTENTS
RCA Phono Inputs (Left and Right) 14
Outputs (Left and Right) 14
Output Level Adjustment 14
Pick-up Grounding Post 14
Technical Specifications 15
5 RB-LI2 Stereo Line Isolation Unit 16
Introduction 16
System Block Diagram 16
Rear Panel Connections and Operation 17
Inputs 17
Isolated Outputs 17
Loop Outputs 17
Output Level Adjustment 17
Internal Jumpers 18
Technical Specifications 18
6 RB-PLI6 6 Way Mono Passive Line Isolation Unit 19
Introduction 19
System Block Diagram 19
CONTENTS
Rear Panel Connections and Operation 20
Inputs 20
Outputs 20
Ground-link Internal Jumpers 20
Technical Specifications 21
AUDIO DISTRIBUTION AMPLIFIERS
7 RB-DA6 & RB-DA6G 6 Way Stereo Distribution Amplifier 22
Introduction 22
System Block Diagram 23
Connections and Operation 24
Stereo Outputs 1-6 (Mono Outputs 1-12) 24
Input Gain Control (RB-DA6) 24
Output Gain Control (RB-DA6G) 24
Stereo/Mono Operation 25
Technical Specifications 25
8 RB-DA4x5 4 Input 4 x 5 Output Distribution Amplifier/Mixer 26
Introduction 26
System Block Diagram 27
Rear Panel Connections and Operation 27
Audio Inputs 1-4 27
D-Type Audio Output Groups 1-4 28
Monitor LEDs 28
Input Level Adjustment 28
Output Level Adjustment 28
Routing Selection 28
Alignment Test Tone 29
Technical Specifications 29
9 RB-DDA6A 6 Way Stereo AES/EBU Digital Distribution Amplifier and
RB-DDA6S 6 Way Stereo S/PDIF Digital Distribution Amplifier 30
Introduction 30
System Block Diagrams 31-32
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Redbox User Handbook No 2
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CONTENTS
Rear Panel Connections and Operations 33
AES/EBU Input 33
AES/EBU Outputs 33
S/PDIF Input 33
S/PDIF Outputs 33
Technical Specifications 34
10 RB-DDA6W 6 Way Word Clock Distribution Amplifier 35
Introduction 35
System Block Diagram 36
Rear Panel Connections and Operations 37
Word Clock Input 37
Word Clock Outputs 37
Technical Specifications 37
HEADPHONE DISTRIBUTION AMPLIFIERS
11 RB-HD1 Stereo Headphone Amplifier & RB-HD2 Dual
Headphone Amplifier 38
Introduction 38
System Block Diagrams 39
Front Panel Connections and Controls 40
Stereo Outputs 1-2 (Mono Outputs1-2) 40
Volume Level Control 40
Stereo Outputs 1-2 (Mono Outputs 1-2) 40
Channel Volume Controls 40
Rear Panel Connections and Operation 41
Main Stereo Inputs (Left and Right) 41
Stereo Input Gain Adjustment (RB-HD1) 41
Stereo/Mono Operation 42
Mono Mix Input (RB-HD1) 42
Mono Mix Input Gain Adjustment (RB-HD1) 42
Local/Remote Control Operation (RB-HD1) 42
Remote Connector (RB-HD1) 42
Technical Specifications 43
CONTENTS
12 RB-HD6 6 Way Headphone Distribution Amplifier 44
Introduction 44
System Block Diagram 45
Rear Panel Connections and Operation 46
Stereo Input (Left and Right) 46
Stereo/Mono Operation 46
Channel Insertion Inputs/Parallel Outputs 46
Removing the Equipment Covers 46
Configuring Insert Inputs/Parallel Outputs 47
Front Panel Connections and Controls 47
Stereo Outputs 1-6 (Mono Outputs 1-6) 47
Master Level Control 48
Channel Volume Controls 48
Technical Specifications 48
13 RB-DHD6 Digital 6 Way Headphone Distribution Amplifier 49
Introduction 49
System Block Diagram 49
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Redbox User Handbook No 2
CONTENTS
Front Panel Indicators & Controls 49
Introduction 49
Sync & Power Indicator 50
Headphone Outputs 50
Volume Control 50
Rear Panel Connections and Operation 50
AES/EBU Input 50
S/PDIF Input 50
Status Select Switches 50
Digital Input Select Button 51
Technical Specifications 51
14 Connectors & Cabling 52
XLR 3 Pin Connectors 52
RCA Phono Connectors 52
D-Type Connectors 53
15 Glossary 54
CONTENTS
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Redbox User Handbook No 2
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FIGURES
Figures
Fig A: Packing List. ii
Fig B: Mains Cable Wire Colours iv
Fig C: Mains Lead Table. iv
Fig D: RB-RK1Small Redbox Front Rack-mount Kit . v
Fig E: RB-RK2 Small Redbox Rear Rack-mount Kit. v
Fig F: RB-RK3 Large Redbox Rear Rack-mount Kit. v
Fig 1-1: RB-UL1 & RB-UL2 Front Panel. 1
Fig 1-2: RB-UL4 Front Panel. 1
Fig 1-3: Block Diagram For a Single Channel (x2 for RB-UL2, x4 for RB-UL4). 1
Fig 1-4: RB-UL1 Rear Panel. 2
Fig 1-5: RB-UL2 Rear Panel. 2
Fig 1-6: RB-UL4 Rear Panel. 2
Fig 2-1: RB-LU4 Front Panel. 5
Fig 2-2: RB-LU4 Block Diagram. 6
Fig 2-3: RB-LU4 Rear Panel. 7
Fig 3-1: RB-BL2 Front Panel. 9
Fig 3-2: RB-BL4 Front Panel. 9
Fig 3-3: RB-BL2/BL4 Block Diagram Single Stereo Channel. 10
Fig 3-4: RB-BL2 Rear Panel. 10
Fig 3-5: RB-BL4 Rear Panel. 11
Fig 4-1: RB-PA2 Front Panel. 13
Fig 4-2: RB-PA2 Block Diagram For a Single Stereo Channel. 13
Fig 4-3: RB-PA2 Rear Panel. 14
Fig 5-1: RB-LI2 Front Panel. 16
Fig 5-2: RB-LI2 System Block Diagram. 16
Fig 5-3: RB-LI2 Rear Panel. 17
Fig 6-1: RB-PLI6 Front Panel. 19
Fig 6-2: RB-PLI6 System Block Diagram. 19
Fig 6-3: RB-PLI6 Rear Panel. 20
Fig 6-4: RB-PLI6 Ground-link Jumper Settings. 20
Fig 7-1: RB-DA6 Front Panel. 22
Fig 7-2: RB-DA6G Front Panel. 22
Fig 7-3: RB-DA6 Block Diagram. 23
Fig 7-4: RB-DA6G Block Diagram. 23
Fig 7-5: RB-DA6 & RB-DA6G Rear Panel. 24
Fig 7-6: RB-DA6 Front Panel. 24
Fig 7-7: RB-DA6G Front Panel. 25
Fig 8-1: RB-DA4x5 Front Panel. 26
Fig 8-2: RB-DA4x5 Block Diagram. 27
Fig 8-3: RB-DA4x5 Rear Panel. 27
Fig 8-4: RB-DA4x5 Audio Output Group15-Way D-Type Plug. 28
FIGURES
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Redbox User Handbook No 2
FIGURES
Fig 8-5: RB-DA4x5 Pinout for Audio Output Group Connector. 28
Fig 8-6: RB-DA4x5 Routing Selection Switch. 28
Fig 8-7: RB-DA4x5 Routing Selection Switch Functions. 29
Fig 9-1: RB-DDA6A/S Front Panel. 30
Fig 9-2: RB-DDA6A System Block Diagram. 31
Fig 9-3: RB-DDA6S System Block Diagram. 32
Fig 9-4: RB-DDA6A Rear Panel. 33
Fig 9-5: RB-DDA6S Rear Panel. 33
Fig 10-1: RB-DDA6W Front Panel. 35
Fig 10-2: RB-DDA6W System Block Diagram. 36
Fig 10-3: RB-DDA6W Rear Panel. 37
Fig 11-1: RB-HD1 Front Panel. 38
Fig 11-2: RB-HD2 Front Panel. 38
Fig 11-3: RB-HD1 Block Diagram. 39
FIGURES
Fig 11-4: RB-HD2 Block Diagram. 39
Fig 11-5: RB-HD1 Front Panel Controls. 40
Fig 11-6: RB-HD2 Front Panel Controls. 40
Fig 11-7: RB-HD1 Rear Panel. 41
Fig 11-8: RB-HD2 Rear Panel. 41
Fig 11-9: RB-HD1 Remote Connector 42
Fig 12-1: RB-HD6 Front Panel. 44
Fig 12-2: RB-HD6 Block Diagram. 45
Fig 12-3: RB-HD6 Rear Panel. 46
Fig 12-4: RB-HD6 Jumper Assignments. 47
Fig 12-5: RB-HD6 Jumper Positions. 47
Fig 12-6: RB-HD6 Front Panel Controls. 47
Fig 12-7: RB-HD6 Master Level Control. 48
Fig 13-1: RB-DHD6 Front Panel. 49
Fig 13-2: RB-DHD6 System Block Diagram. 49
Fig 13-3: RB-DHD6 Front Panel Controls. 49
Fig 13-4: RB-DHD6 Rear Panel. 50
Fig 13-5: RB-DHD6 Status Select Switches. 50
Fig 14-1: XLR Connectors. 52
Fig 14-2: RCA Phono Connector. 52
Fig 14-3: ¼” Jack Connector. 52
Fig 14-4: 25 Way D-Type Connectors. 53
Fig 14-5: 15 Way D-Type Connectors. 53
Fig 14-6: 9 Way D-Type Connectors. 53
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Redbox User Handbook No 2
i
WARRANTY
Warranty
Warranty and Liability - important the purchaser is advised to read this clause
(a) The Company agrees to repair or (at its discretion) replace Goods which are found to
be defective (fair wear and tear excepted) and which are returned to the Company
within 12 months of the date of despatch provided that each of the following
are satisfied:
(i) Notification of any defect is given to the Company immediately upon its
becoming apparent to the Purchaser;
(ii) The Goods have only been operated under normal operating conditions and
have only been subject to normal use (and in particular the Goods must have
been correctly connected and must not have been subject to high voltage or
to ionising radiation and must not have been used contrary to the Company’s
technical recommendations);
(iii) The Goods are returned to the Company’s premises at the Purchaser’s expense;
(iv) Any Goods or parts of Goods replaced shall become the property of the
Company;
(v) No work whatsoever (other than normal and proper maintenance) has been
carried out to the Goods or any part of the Goods without the Company’s prior
written consent;
(vi) The defect has not arisen from a design made, furnished or specified by the
Purchaser;
(vii) The Goods have been assembled or incorporated into other goods only in
accordance with any instructions issued by the Company;
(viii) The defect has not arisen from a design modified by the Purchaser;
(ix) The defect has not arisen from an item manufactured by a person other than
the Company. In respect of any item manufactured by a person other than the
Company, the Purchaser shall only be entitled to the benefit of any warranty or
guarantee provided by such manufacturer to the Company.
(b) In respect of computer software supplied by the Company the Company does not
warrant that the use of the software will be uninterrupted or error free.
(c) The Company accepts liability:
(i) For death or personal injury to the extent that it results from the negligence of
the Company, its employees (whilst in the course of their employment) or its
agents (in the course of the agency);
WARRANTY
Page 10
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Redbox User Handbook No 2
WARRANTY
(ii) For any breach by the Company of any statutory undertaking as to title, quiet
possession and freedom from encumbrance.
(d) Subject to conditions (a) and (c) from the time of despatch of the Goods from the
Company’s premises the Purchaser shall be responsible for any defect in the Goods
or loss, damage, nuisance or interference whatsoever consequential economic or
otherwise or wastage of material resulting from or caused by or to the Goods. In
particular the Company shall not be liable for any loss of profits or other economic
losses. The Company accordingly excludes all liability for the same.
(e) At the request and expense of the Purchaser the Company will test the Goods to
ascertain performance levels and provide a report of the results of that test. The
report will be accurate at the time of the test, to the best of the belief and Knowledge
of the Company, and the Company accepts no liability in respect of its accuracy
beyond that set out in Condition (a).
(f) Subject to Condition (e) no representation, condition, warranty or other term, express
WARRANTY
or implied (by statute or otherwise) is given by the Company that the Goods are of
any particular quality or standard or will enable the Purchaser to attain any particular
performance or result, or will be suitable for any particular purpose or use under
specific conditions or will provide any particular capacity, notwithstanding that the
requirement for such performance, result or capacity or that such particular purpose
or conditions may have been known (or ought to have been known) to the Company,
its employees or agents.
(g) (i) To the extent that the Company is held legally liable to the Purchaser for any
single breach of contract, tort, representation or other act or default, the
Company’s liability for the same shall not exceed the Price of the Goods.
(ii) The restriction of liability in Condition (g)(i) shall not apply to any liability
accepted by the Seller in Condition (c).
(h) Where the Goods are sold under a consumer transaction (as defined by the
Consumer Transactions (Restrictions on Statements) Order 1976) the statutory
rights of the Purchaser are not affected by these Conditions of Sale.
Unpacking the Redbox
The Redbox is shipped with the following equipment. Please check your packaging to
ensure that you have all of the items below. If anything is missing, please contact the
supplier of your equipment immediately.
Item Quantity
Redbox audio interface 1
IEC Mains lead fitted with moulded mains plug 1
Handbook and warranty card 1
Fig A: Packing List.
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Redbox User Handbook No 2
iii
SA FE TY & I NS TA LL ATI ON
INFORMATION
Each Redbox is shipped in protective packaging and should be inspected for damage before
use. Where an item is found to have transit damage, notify the carrier immediately with all
the relevant details of the shipment. Packing materials should be kept for inspection and
also for if the product needs to be returned.
Returning the Warranty Card
In order to register the date of purchase so that we can keep you informed of any design
improvements or modifications, it is important to complete the warranty registration
document that is enclosed and return it to Sonifex Ltd in the UK, or register online at
www.sonifex.co.uk/register
For your own records you should write down the serial number (which can be found on the
rear of the Redbox.
Serial Number ………………………………………
Safety Information
Safety of Mains Operated Equipment
This equipment has been designed to meet the safety regulations currently advised
in the country of purchase and it conforms to the safety regulations specified by
use of the CE Mark.
Warning : There are no user serviceable parts inside the equipment. If you should ever
need to look inside the unit, always disconnect the mains supply before removing the
equipment covers.
SAFETY & INSTALLATION INFORMATION
Voltage Setting Checks
Ensure that the machine operating voltage is correct for your mains power supply by
checking the rear panel of your Redbox. The available voltage settings are 115V, or 230V.
Please note that all Redboxes are either switchable between 115V and 230V, or have a
universal power supply.
Fuse Rating
The Redboxes are supplied with a single fuse in the live conducting path of the power
infeed at the power supply. For reasons of safety it is important that the correct rating
and type of fuse is used. Incorrectly rated fuses could present a possible fire hazard, under
equipment fault conditions. See the Technical Specifications of each product for the fuse
rating. The active fuse is fitted on the outside rear panel of the unit.
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Redbox User Handbook No 2
SA FE TY & I NS TA LL ATI ON
INFORMATION
Power Cable and Connection
An IEC power connector is supplied with the Redbox, which has a moulded plug, attached
– this is a legal requirement. If no moulded plug has been supplied with your Redbox, please
contact your supplier, because an IEC connector is always supplied from the Sonifex factory.
If for any reason, you need to use the Redbox with a different power cable, you should use
the following wiring guidelines:
Wire Colour Connection
Green, or green and yellow Earth (E)
Blue, or Black Neutral (N)
Brown, or Red Live (L)
Fig B: Mains Cable Wire Colours
Ordering the Correct Mains Lead
When ordering a Redbox from Sonifex, it is helpful if you can specify your required
operating voltage and mains lead. After the product code add:
UK, for 230V, UK 3 pin to IEC lead
EC, for 230V, European Schuko 2 pin to IEC lead
US, for 115V, 3 pin to IEC lead
AU for 230V, Australasian 3 pin to IEC lead
Fig C: Mains Lead Table.
E.g. order RB-BL2 UK for a UK IEC lead to be supplied.
Installation Information
Atmosphere
The units should be installed in an area that is not subject to excessive temperature
SAFETY & INSTALLATION INFORMATION
variation (<0°C, >50°C), moisture, dust or vibration.
Electromagnetic Radiation
The cover is connected to earth by means of the fixing screws. It is essential to maintain
this earth ground connection to ensure a safe operating environment and provide
electromagnetic shielding.
Fitting Redboxes
Redboxes can be fixed to the underside of a mixing desk, or other surfaces using 4.2mm
holes in the sides and fixed with 2 x M4 screws or 2 x No. 6 countersink wood screws.
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Redbox User Handbook No 2
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SA FE TY & I NS TA LL ATI ON
INFORMATION
They can also be rack-mounted, with either the front, or rear of the Redbox positioned at the
front of the rack:
Front Mounting Redboxes: For rack mounting smaller (28cm) units the optional RB-RK1
(Red) or RB-RK1B (Black) kit can be used (which include 4 off M6 panel fixing screws).
Fig D: RB-RK1Small Redbox Front Rack-mount Kit .
Wherever you see this symbol an RB-RK1 front panel rack kit can be used :
Rear Mounting Redboxes: For rear panel mounting you can use either the RB-RK2, or
RB-RK3, depending on the size of your Redbox.
RB-RK2 1U rear panel rack kit for small Redbox range, e.g., RB-BL2
Fig E: RB-RK2 Small Redbox Rear Rack-mount Kit.
e.g. for fitting an RB-BL2:
SAFETY & INSTALLATION INFORMATION
Wherever you see this symbol an RB-RK2 small Redbox rear panel 19” rack kit can be used :
RB-RK3 1U rear panel rack kit for large Redbox range, e.g., RB-DA6
Fig F: RB-RK3 Large Redbox Rear Rack-mount Kit.
e.g. for fitting an RB-DA6:
Wherever you see this symbol an RB-RK3 large Redbox rear panel 19” rack kit can be used :
Note: When fitting the rear-mounting rack-kits, a notch has been
left on the inside of the right-hand rack-piece for the mains cable to
pass through. Make sure that the mains cable has been put through
the notch before attaching the right hand rack-piece.
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SA FE TY & I NS TA LL ATI ON
INFORMATION
WEEE & RoHS Directives - Sonifex Statement
The Waste Electrical and Electronic Equipment (WEEE) Directive was agreed on
13 February 2003, along with the related Directive 2002/95/EC on Restrictions
of the use of certain Hazardous Substances in electrical and electronic
equipment (RoHS).
The Waste Electrical and Electronic Equipment Directive (WEEE) aims to minimise the
impacts of electrical and electronic equipment on the environment during their life times
and when they become waste. It applies to a huge spectrum of products. It encourages
and sets criteria for the collection, treatment, recycling and recovery of waste electrical and
electronic equipment. All products manufactured by Sonifex Ltd have the WEEE directive
label placed on the case. It gives a contact for individuals who are unsure about the correct
procedure when the product has reached its “end of use”.
Sonifex Ltd will be happy to give you information about local organisations that can
reprocess the products, or alternatively all products that have reached “end of use” can be
returned to Sonifex and will be reprocessed correctly free of charge.
Sonifex Ltd has phased out the use of certain hazardous substances identified in the
European Union’s Restriction of Hazardous Substances (RoHS) directive. The RoHS directive
limits the use of certain hazardous substances currently used in EEE manufacture, including
lead, mercury, cadmium, hexavalent chromium, and halide-containing compounds PBB
(polybrominated biphenyl) and PBDE (polybrominated diphenyl ether). Elimination of these
substances will result in more environmentally friendly recycling of electronic equipment.
For the products which Sonifex manufacture, the main area where products were affected
was in the use of lead for manufacturing and assembling electronics circuit boards.
Sonifex Ltd practices lead-free (LF) manufacturing processes. LF solder is used on the
surface-mount PCB manufacturing processes and for hand soldering. The printed circuit
boards (PCBs) used are either gold plated, or immersion tin plated, both of which use no
lead. Historically the PCBs were hot air solder levelled (HASL) PCBs which used tin/lead
based solder.
The manufacturing processes include the assembly of purchased components from various
sources. Product is offered as RoHS compliant, or LF, only after sufficient evidence is received
SAFETY & INSTALLATION INFORMATION
from the component manufacturers that their components are RoHS compliant. Sonifex
Ltd relies solely on the distributor, or manufacturer, of the components for identification of
RoHS compliance. Thus whilst every effort is made to ensure compliance, Sonifex Ltd makes
no warranty, or certification, or declaration of compliance concerning said components.
Sonifex Ltd defines “Lead Free” as pertaining to any product, which has been manufactured
by Sonifex Ltd using components which have been declared by the manufacturers as
“Lead Free”. All statements by Sonifex Ltd of RoHS compliance are based on component
manufacturer documentation.
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Redbox User Handbook No 2
Page 15
MATCHING CONVERTERS
Left Input
Consumer/
Unbalanced
Phono
Gain
Left Output
Professional/Balanced
Right Input
Consumer/
Unbalanced
Phono
Gain
Right Output
Professional/Balanced
1 RB-UL1 Single, RB-UL2 Dual & RB-UL4 Quad Stereo Unbalanced
To Balanced Converters
Introduction
1
Fig 1-1: RB-UL1 & RB-UL2 Front Panel.
Fig 1-2: RB-UL4 Front Panel.
The RB-UL1 single, RB-UL2 dual & RB-UL4 quad stereo units are used for interfacing
domestic, or semi-pro unbalanced equipment to professional balanced line levels.
All connections are on the rear panel. The RCA unbalanced inputs have an impedance of
10kΩ bridging and are routed to the balanced XLR-3 outputs with an output impedance
of <50Ω.
The RB-UL1 has two inputs & outputs, the RB-UL2 has four inputs & outputs and the RB-UL4
has eight inputs & outputs.
The output gain can be individually adjusted for left and right channels by using pre-set
potentiometers accessible through the rear panel. A LED power indicator on the front panel
displays the power supply connection.
System Block Diagram
MATCHING CONVERTERS - RB-UL1, RB-UL2, RB-UL4
Fig 1-3: Block Diagram For a Single Channel (x2 for RB-UL2, x4 for RB-UL4).
Redbox User Handbook No 2
1
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Redbox User Handbook No 2
1
MATCHING CONVERTERS
Rear Panel Connections and Operation
RCA
Phono
Inputs
Output
Level
Adjustment
Stereo
Outputs
Fig 1-4: RB-UL1 Rear Panel.
Fig 1-5: RB-UL2 Rear Panel.
RCA
Phono
Inputs
MATCHING CONVERTERS - RB-UL1, RB-UL2, RB-UL4
Fig 1-6: RB-UL4 Rear Panel.
RCA
Phono
Inputs
Output
Level
Adjustment
Stereo Balanced
Outputs
Output
Level
Adjustment
Stereo Balanced
Outputs
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Redbox User Handbook No 2
3
MATCHING CONVERTERS
RCA Phono Inputs (Left and Right)
The stereo left and right RCA inputs are unbalanced and have an impedance of 10kΩ. They
are routed to the stereo balanced XLR 3 pin output connectors.
Outputs (Left and Right)
The XLR 3 pin output plug connectors are electronically balanced with an output
impedance of <50Ω. They have the following connections:
Pin 1: Screen
Pin 2: Phase
Pin 3: Non-phase
Output Level Adjustment
The output gain can be individually adjusted for left and right channels through
pre-set potentiometers which are accessible through the rear panel. The gain range
of the unbalanced to balanced converter is -15dBu to +15dBu ref -15dBu into the
unbalanced input.
1
MATCHING CONVERTERS - RB-UL1, RB-UL2, RB-UL4
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Redbox User Handbook No 2
1
MATCHING CONVERTERS
Technical Specifications
Audio Specifications
Maximum Input Level: +28dBu
Input Impedance: >10kΩ
Output Impedance: <50Ω
Maximum Output Level: +28dBu
Distortion: 0.01% THD @ 1kHz ref +8dB output
Noise: -100dB unity gain, ref +8dB output
Common Mode Rejection: >66dB typically
Frequency Response: 20Hz to 20kHz ±0.1dB (600Ω load, ref 1kHz)
Gain Range: Balanced output: -15dBu to 15dBu, ref -15dBu into
unbalanced RCA input
Connections
Inputs: 2, 4 (RB-UL2) or 8 (RB-UL4) x RCA phono (unbalanced)
Outputs: 2, 4 (RB-UL2) or 8 (RB-UL4) x XLR 3 pin male (balanced)
Mains Input: Filtered IEC, 110V-120V, or 220-240V switchable, fused,
6W maximum
Fuse Rating: Anti-surge fuse 100mA 20 x 5mm (230VAC)
Anti-surge fuse 250mA 20 x 5mm (115VAC)
Equipment Type
RB-UL1: Single stereo unbalanced to balanced converter
RB-UL2: Dual stereo unbalanced to balanced converter
RB-UL4: Quad stereo unbalanced to balanced converter
Physical Specifications
RB-UL1 & RB-UL2:
Dimensions (Raw): 28cm (W ) x 10.8cm (D) x 4.2cm (H) (1U)
Dimensions (Boxed): 36cm (W) x 20.5cm (D) x 6cm (H)
Weight RB-UL1: Nett: 1.00kg Gross: 1.45kg
Weight RB-UL2: Nett: 1.05kg Gross: 1.5kg
RB-UL4:
Dimensions (Raw): 48cm (W ) x 10.8cm (D) x 4.2cm (H) (1U)
Dimensions (Boxed): 53cm (W) x 20.5cm (D) x 6cm
Weight: Nett: 1.3kg Gross: 1.9kg
MATCHING CONVERTERS - RB-UL1, RB-UL2, RB-UL4
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Redbox User Handbook No 2
5
MATCHING CONVERTERS
2 RB-LU4 Quad Stereo Balanced To Unbalanced Converter
Introduction
Fig 2-1: RB-LU4 Front Panel.
The RB-LU4 is a quad stereo unit for interfacing professional balanced equipment to
domestic, or semi-pro unbalanced line levels.
All connections are on the rear panel. The eight XLR-3 electronically balanced inputs have an
impedance of 20kΩ bridging and are routed to eight unbalanced RCA phono outputs with
an output impedance of <50Ω.
The output gain can be individually adjusted for left and right channels by using pre-set
potentiometers accessible through the rear panel. An LED power indicator is situated on the
front panel, which displays the power supply connection.
2
MATCHING CONVERTERS - RB-LU4
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Redbox User Handbook No 2
2
Left Input 1
Professional/
Balanced
Left Output 1
Consumer/Unbalanced
Phono
Gain
Right Input 1
Professional/
Balanced
Right Output 1
Consumer/Unbalanced
Phono
Gain
Left Input 2
Professional/
Balanced
Left Output 2
Consumer/Unbalanced
Phono
Gain
Right Input 2
Professional/
Balanced
Right Output 2
Consumer/Unbalanced
Phono
Gain
Left Input 3
Professional/
Balanced
Left Output 3
Consumer/Unbalanced
Phono
Gain
Right Input 3
Professional/
Balanced
Right Output 3
Consumer/Unbalanced
Phono
Gain
Left Input 4
Professional/
Balanced
Left Output 4
Consumer/Unbalanced
Phono
Gain
Right Input 4
Professional/
Balanced
Right Output 4
Consumer/Unbalanced
Phono
Gain
MATCHING CONVERTERS - RB-LU4
MATCHING CONVERTERS
System Block Diagram
Fig 2-2: RB-LU4 Block Diagram.
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Redbox User Handbook No 2
7
MATCHING CONVERTERS
2
Rear Panel Connections and Operation
Stereo Balanced
Inputs
Fig 2-3: RB-LU4 Rear Panel.
Inputs 1-4 (Left and Right)
The XLR 3 pin sockets used for the left and right channel inputs of Input 1 are electronically
balanced and have an impedance of 20kΩ bridging. They are routed to an unbalanced
RCA (phono) output with an output impedance of <50Ω. Each XLR has the following
connections:
Pin 1: Screen
Pin 2: Phase
Pin 3: Non-phase
RCA Phono Outputs 1-4 (Left and Right)
These RCA (phono) outputs are unbalanced and have an output impedance of <50Ω.
Output Level Adjustment
The output gain can be individually adjusted for left and right channels through pre-set
potentiometers which are accessible through the rear panel. The gain of the balanced to
unbalanced converter is variable within a range of -28dBu to +15dBu ref. -15dBu into the
balanced input.
RCA
Phono
Outputs
Output
Level
Adjustment
MATCHING CONVERTERS - RB-LU4
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Redbox User Handbook No 2
2
MATCHING CONVERTERS
Technical Specifications
Audio Specifications
Maximum Input Level: +28dBu
Input Impedance (XLR): >20kΩ balanced bridging
Output Impedance (RCA) : <50Ω
Maximum Output Level: +22dBu
Distortion: 0.01% THD @ 1kHz, ref +8dBu output
Noise: -100dB, unity gain, ref +8dBu output
Common Mode Rejection: >66dB typically
Frequency Response: 20Hz to 20kHz ±0.1dB (600Ω load, ref 1kHz)
Gain Range: Unbalanced Output: -28dBu to +15dBu, ref -15dBu into
balanced XLR input
Connections
Inputs: 8 x XLR 3 pin female (Balanced)
Outputs: 8 x RCA phono (Unbalanced)
Mains Input: Filtered IEC, 110V-120V, or 220-240V switchable, fused,
6W maximum
Fuse Rating: Anti-surge fuse 100mA 20 x 5mm (230VAC)
Anti-surge fuse 250mA 20 x 5mm (115VAC)
Equipment Type
RB-LU4: Quad stereo balanced to unbalanced converter
Physical Specifications
Dimensions (Raw): 48cm (W) x 10.8cm (D) x 4.2cm (H) (1U)
Dimensions (Boxed): 53cm (W) x 20.5cm (D) x 6cm (H)
Weight: Nett: 1.3kg Gross: 1.9kg
MATCHING CONVERTERS - RB-LU4
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Redbox User Handbook No 2
9
MATCHING CONVERTERS
3 RB-BL2 Single & RB-BL4 Dual Bi-Directional
Matching Converter
Introduction
3
Fig 3-1: RB-BL2 Front Panel.
Fig 3-2: RB-BL4 Front Panel.
The RB-BL2 is a bi-directional stereo unit for interfacing domestic, or semi-pro unbalanced
equipment to professional balanced line levels, and vice-versa. The RB-BL4 has dual bidirectional stereo capability.
All connections are on the rear panel. The XLR-3 electronically balanced inputs have an
impedance of 20kΩ bridging and are routed to unbalanced RCA (phono) outputs with an
output impedance of <50Ω.
The RCA unbalanced inputs have an impedance of 10kΩ bridging and are routed to
balanced XLR-3 outputs with an output impedance of <50Ω.
The output gain can be individually adjusted for left and right channels by using pre-set
potentiometers accessible through the rear panel. An LED power indicator on the front
panel displays the power supply connection.
MATCHING CONVERTERS - RB-BL2 & RB-BL4
Page 24
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Redbox User Handbook No 2
3
Left Input 1
Professional/
Balanced
Left Output 1
Consumer/Unbalanced
Phono
Gain
Right Input 1
Professional/
Balanced
Left Input 2
Consumer/
Unbalanced
Right Input 2
Consumer/
Unbalanced
Right Output 1
Consumer/Unbalanced
Left Output 2
Professional/Balanced
Right Output 2
Professional/Balanced
Phono
Gain
Phono
Gain
Phono
Gain
MATCHING CONVERTERS
System Block Diagram
Fig 3-3: RB-BL2/BL4 Block Diagram Single Stereo Channel.
(Note RB-BL4 contains 2 of these circuits)
MATCHING CONVERTERS - RB-BL2 & RB-BL4
Rear Panel Connections and Operation
Unbalanced Output
Adjustment
Stereo
Fig 3-4: RB-BL2 Rear Panel.
Balanced
Inputs
Level
Outputs
Balanced Output
Level
Adjustment
RCA
Phono
RCA
Phono
Inputs
Stereo
Balanced
Outputs
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Redbox User Handbook No 2
11
MATCHING CONVERTERS
3
RCA
Phono
Outputs
Balanced
Inputs
Fig 3-5: RB-BL4 Rear Panel.
RCA Phono
Inputs
Balanced Output
LevelControl
Balanced
Outputs
Balanced
Inputs
Unbalanced Output
Level Control
RCA
Phono
Outputs
RCA Phono
Inputs
Balanced
Outputs
Balanced Output
Level Control
Balanced to Unbalanced Connections
Inputs 1 (& 3) (Left & Right)
The XLR 3 pin sockets used for the left and right channel signals of Inputs 1 & 3 are
electronically balanced and have an impedance of 20kΩ bridging. They are routed to
unbalanced RCA (phono) outputs with an output impedance of <50Ω. Each XLR has the
following connections:
Pin 1: Screen.
Pin 2: Phase.
Pin 3: Non-phase.
RCA Phono Outputs 1 (& 3) (Left & Right)
These RCA (phono) outputs are unbalanced and have an output impedance of <50Ω.
Output Level Adjustment
The output gain can be individually adjusted for left and right channels through pre-set
potentiometers which are accessible through the rear panel. The gain of the balanced
to unbalanced converter is variable within a range of 0dBu to -28dBu ref -0dBu into the
balanced input.
MATCHING CONVERTERS - RB-BL2 & RB-BL4
Unbalanced to Balanced Connections
RCA Phono Inputs 2 (& 4) (Left & Right)
The left and right RCA inputs 2 & 4 are unbalanced and have an impedance of 10kΩ.
They are routed to the balanced XLR 3 pin outputs 2 & 4.
Outputs 2 (& 4) (Left & Right)
The XLR 3 pin output plug connectors are electronically balanced with an output
impedance of <50Ω. They have the following connections:
Pin 1: Screen.
Pin 2: Phase.
Pin 3: Non-phase.
Page 26
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Redbox User Handbook No 2
3
MATCHING CONVERTERS
Technical Specifications
Audio Specifications
Maximum Input Level: +28dBu
Maximum Output Level: +28dBu
Input Impedance (RCA) : >10kΩ unbalanced
Input Impedance (XLR) : >20kΩ balanced bridging
Output Impedance (RCA) : <50Ω
Output Impedance (XLR) : <50Ω
Distortion: 0.01% THD @ 1kHz, ref +8dBu output
Noise: -100dB, unity gain, ref +8dBu output
Common Mode Rejection: >66dB typically
Frequency Response: 20Hz to 20kHz ±0.1dB (600Ω load, ref 1kHz)
Gain Range: Unbalanced Output: -28dBu to +15dBu, ref -15dBu into
balanced XLR input
Gain Range: Balanced Output: -15dBu to +15dBu, ref -15dBu
into unbalanced RCA input
Connections
Inputs: 2 (4 on RB-BL4) x XLR 3 pin female (balanced),
2 (4 on RB-BL4) x RCA phono (unbalanced)
Outputs: 2 (4 on RB-BL4) x XLR 3 pin male (balanced),
2 (4 on RB-BL4) x RCA phono (unbalanced)
Mains Input: Filtered IEC, 110V-120V, or 220-240V switchable, fused,
6W maximum
Fuse Rating: Anti-surge fuse 100mA 20 x 5mm (230VAC)
Anti-surge fuse 250mA 20 x 5mm (115VAC)
Equipment Type
RB-BL2: Single stereo bi-directional matching converter
RB-BL4: Dual stereo bi-directional matching converter
Physical Specification
RB-BL2:
Dimensions (Raw): 28cm (W ) x 10.8cm (D) x 4.2cm (H) (1U)
Dimensions (Boxed): 36cm (W) x 20.5cm (D) x 6cm (H)
MATCHING CONVERTERS - RB-BL2 & RB-BL4
Weight: Nett: 1.0kg Gross: 1.4kg
RB-BL4:
Dimensions (Raw) 48cm (W) x 10.8cm (D) x 4.2cm (H) (1U)
Dimensions (Boxed) 53cm ( W) x 20.5cm (D) x 6cm (H)
Weight Nett: 1.3kg Gross: 1.9kg
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Redbox User Handbook No 2
13
MATCHING CONVERTERS
RIAA
Gain
Phono
RIAA
Gain
Left Output
Professional/Balanced
Right Output
Professional/Balanced
Left Input
Phono
Right Input
Phono
4 RB-PA2 Dual Stereo RIAA Phono Amplifier
Introduction
4
Fig 4-1: RB-PA2 Front Panel.
The RB-PA2 is a dual stereo RIAA equalised phono amplifier. This record player preamp
amplifies the small signal from your pick up cartridge (either moving magnet or high output
moving coil magnetic) and provides the necessary RIAA equalisation required for vinyl
records, to match it to a line input of your mixer, or amplifier. It uses a clean RIAA response
making it ideal for use with broadcast turntables and DJ decks and where vinyl records are
being archived to CD for high quality transfers, or for converting albums to mp3.
It operates with phono cartridges with a nominal output of 1mV to 25mV and has been
specifically tested to work with the Technics SL-1200™ and 1210™ range of turntables.
Quality high specification components have been used together with low noise, fast acting
operational amplifiers to produce a superbly transparent signal path. Additionally, the
RB-PA2 runs without a rumble filter to produce a powerful bass response.
The RB-PA2 is a dual stereo unit to interface up to two turntables. The inputs are phono
connectors with Neutrik XLR connectors for the balanced outputs, which may be wired
unbalanced if required. Output gain is individually adjustable for left and right channels in
the range 35dB to 65dB by using pre-set potentiometers. Frequency response is held
within 0.5dB of the RIAA curve and noise is typically better than -84dB RMS A weighted at
40dB gain.
System Block Diagram
MATCHING CONVERTERS - RB-PA2
Fig 4-2: RB-PA2 Block Diagram For a Single Stereo Channel.
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Redbox User Handbook No 2
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MATCHING CONVERTERS
Rear Panel Connections and Operation
Pick-up
Grounding
Post
RCA
Phono
Inputs
Fig 4-3: RB-PA2 Rear Panel.
RCA Phono Inputs (Left and Right)
The stereo left and right RCA inputs are unbalanced and have an impedance of 47kΩ. They
are routed to the stereo balanced XLR 3 pin output connectors.
Outputs (Left and Right)
The XLR 3 pin output plug connectors are electronically balanced with an output
impedance of <50Ω. They have the following connections:
Pin 1: Screen
Pin 2: Phase
Pin 3: Non-phase
MATCHING CONVERTERS - RB-PA2
Output Level Adjustment
The output gain can be individually adjusted for left and right channels through pre-set
potentiometers which are accessible through the rear panel. The gain range of each channel
is adjustable between 30dB gain and 58dB gain.
Pick-up Grounding Post
This acts as an earth ground connection to connect to a turntable pick-up ground point.
Output
Level
Adjustments
Stereo
Balanced
Outputs
RCA
Phono
Inputs
Pick-up
Grounding
Post
Stereo
Balanced
Outputs
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Redbox User Handbook No 2
15
MATCHING CONVERTERS
Technical Specifications
Audio Specifications
Maximum Input Level: +28dBu
Input Impedance: >47kΩ
Input Sensitivity Range: 1mV to 25mV (ref 1kHz)
Maximum Output Level: +28dBu
Output Impedance: <50Ω
Output Gain Range: Adjustable 38dB to 58dB gain via 4 multi-turn pots
Crosstalk: Better than -80dBu at 1kHz
Frequency Response: 10Hz-150kHz (-3dB)
RIAA Accuracy: Within 0.5dB of RIAA curve
Distortion: 0.01% THD @ 1kHz, ref +8dBu output
Noise: -77dB (CCIR Q-Pk, 20Hz-20kHz)
Headroom: 27dB for 3mV input
Dynamic Range: 90dB
Connections
Inputs: 4 x RCA phono (unbalanced)
Outputs: 4 x XLR 3 pin male (balanced)
Earth Tag: Grounding turret tag
Mains Input: Filtered IEC, 110V-120V, or 220-240V switchable,
fused 6W maximum
Fuse Rating: Anti-surge fuse 100mA 20 x 5mm (230VAC)
Anti-surge fuse 250mA 20 x 5mm (115VAC)
Equipment Type
RB-PA2: Dual stereo phono amplifier and RIAA gram amplifier
4
MATCHING CONVERTERS - RB-PA2
Physical Specifications
Dimensions (Raw): 28cm (W ) x 10.8cm (D) x 4.2cm (H) (1U)
Dimensions (Boxed): 36cm (W) x 20.5cm (D) x 6cm (H)
Weight RB-PA2 Nett: 1.1kg Gross: 1.5kg
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5
Gain
Input
Isolated Output
Transformer Balanced Mode
Ground Link
Jumper
Loop
Output
X2
MATCHING CONVERTERS
5 RB-LI2 Stereo Line Isolation Unit
Introduction
Fig 5-1: RB-LI2 Front Panel.
The RB-LI2 stereo line isolation unit is used to isolate audio signals from inter area ground
hum loops, which could be caused by equipment being powered by different mains power
supplies, or different phases on the same supply. The input and output are connected
together through a transformer, which has internal jumpers allowing the outputs to be
balanced about ground.
There is also a loop-through output, so that the RB-LI2 can be inserted into a line, forming a
transformer balanced distribution point.
This unit is useful where audio is required to be driven over a relatively long length of cable.
By isolating the signal using transformers, ground loop currents that can be present in nonisolated signals, are eradicated completely.
System Block Diagram
MATCHING CONVERTERS - RB-LI2
Fig 5-2: RB-LI2 System Block Diagram.
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Redbox User Handbook No 2
17
Rear Panel Connections and Operation
MATCHING CONVERTERS
5
Isolated
Output
Loop Output Loop Output
Output Level
Adjustment
Fig 5-3: RB-LI2 Rear Panel.
Inputs
There are 2 input XLR 3 pin sockets. They have the following connections:
Pin 1: Screen
Pin 2: Phase
Pin 3: Non-phase
Isolated Outputs
Each of the 2 inputs has a corresponding isolated output, an XLR 3 pin plug with the
following connections:
Pin 1: Screen
Pin 2: Phase
Pin 3: Non-phase
Loop Outputs
Each of the 2 inputs has a corresponding loop-through output, an XLR 3 pin plug with the
following connections:
Pin 1: Screen
Pin 2: Phase
Pin 3: Non-phase
Output Level Adjustment
The isolated outputs can be individually adjusted using pre-set potentiometers, which are
accessible through the rear panel. The gain range of the stereo line isolation unit is -15dB to
+13.5dB (28.5dB).
Input Input
Isolated
Output
Output Level
Adjustment
MATCHING CONVERTERS - RB-LI2
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5
MATCHING CONVERTERS
Internal Jumpers
The unit has jumpers that are used to balance the output about ground. By default these are
not fitted when the unit leaves the factory.
To get inside the RB-LI2, first ensure that it has been disconnected from the mains power
and that the mains IEC lead to the unit has been removed. Observing anti-static precautions,
undo the four-crosshead screws on the back panel at the far left and far right of the panel
(2 at each end). Also undo the small brass screws, which hold the top and bottom panels to
the rear panel. The rear panel should slide backwards out of the unit together with the main
circuit board.
Fig 5-4: RB-LI2 Jumper Positions on the PCB.
Technical Specifications
Audio Specification
Output Impedance: <150Ω
Frequency Response: 10Hz to 36kHz ±0.5dB
Common Mode Rejection: <64dB
Distortion: 0.5% THD @ 40Hz, ref +17dBu output
MATCHING CONVERTERS - RB-LI2
Noise: -100dB unity gain ref +8dB
Gain Range: -15dB to +13.5dB (28.5dB)
Connections
Inputs: 2 x XLR 3 pin female
Isolated Outputs: 2 x XLR 3 pin male
Loop Outputs: 2 x XLR 3 pin male
Fuse Rating: Anti-surge fuse 100mA 20 x 5mm (230VAC)
Anti-surge fuse 250mA 20 x 5mm (115VAC)
Equipment Type
RB-LI2: Stereo line isolation unit
Physical Specifications
Dimensions (Raw): 28cm (W ) x 10.8cm (D) x 4.2cm (H) (1U)
Dimensions (Boxed): 36cm (W) x 20.5cm (D) x 6cm (H)
Weight: Nett: 1.10kg Gross: 1.50kg
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Redbox User Handbook No 2
19
MATCHING CONVERTERS
Ground Balancing
Input Output
X6
6 RB-PLI6 6 Way Mono Passive Line Isolation Unit
Introduction
Fig 6-1: RB-PLI6 Front Panel.
The RB-PLI6 6 way mono passive line isolation unit is used to isolate audio signals from inter
area ground hum loops, which could be caused by equipment being powered by different
mains power supplies or phases on the same supply.
The input and output are connected together through a transformer and the unit has
internal jumpers allowing the inputs and/or outputs to be balanced about ground. The unit
requires no mains power for operation.
This unit is useful where audio is required to be driven over a relatively long length of cable.
By isolating the signal using transformers, ground loop currents that can be present in nonisolated signals, are eradicated completely.
System Block Diagram
6
MATCHING CONVERTERS - RB-PLI6
Fig 6-2: RB-PLI6 System Block Diagram.
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6
MATCHING CONVERTERS - RB-PLI6
MATCHING CONVERTERS
Rear Panel Connections and Operation
Outputs
Inputs
Fig 6-3: RB-PLI6 Rear Panel.
Inputs
There are 6 off XLR 3 pin socket inputs. They have the following connections:
Pin 1: Screen
Pin 2: Phase
Pin 3: Non-phase
Outputs
There are 6 off XLR 3 pin plug outputs. They have the following connections:
Pin 1: Screen
Pin 2: Phase
Pin 3: Non-phase
Ground-link Internal Jumpers
The unit has jumpers that are used to balance either the input, or the output, about ground.
By default these are not fitted when the unit leaves the factory.
To get inside the RB-PLI6, observing anti-static precautions, undo the four crosshead screws
on the back panel at the far left and far right of the panel (2 at each end). Also undo the
small brass screws, which hold the top and bottom panels to the rear panel. The rear panel
should slide backwards out of the unit together with the main circuit board.
Fig 6-4: RB-PLI6 Ground-link Jumper Settings.
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Redbox User Handbook No 2
21
MATCHING CONVERTERS
Technical Specifications
Audio Specification
Output Impedance: <150Ω
Distortion: 0.5% THD @ 40Hz, ref +17dBu output
Common Mode Rejection: <64dB typically
Frequency Response: 10Hz to 36kHz ±0.5dB
Connections
Inputs: 6 x XLR 3 pin female (balanced)
Outputs: 6 x XLR 3 pin male (balanced)
Equipment Type
RB-PLI6: 6 way mono passive line isolation unit
Physical Specifications
Dimensions (Raw): 48cm (W ) x 10.8cm (D) x 4.2cm (H-1U nominally)
Dimensions (Boxed): 53cm (W) x 20.5cm (D) x 6cm
Weight: Nett: 1.5kg Gross: 1.9kg
6
MATCHING CONVERTERS - RB-PLI6
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Redbox User Handbook No 2
7
AUDIO DISTRIBUTION
AMPLIFIERS
7 RB-DA6 & RB-DA6G 6 Way Stereo Distribution Amplifier
Introduction
Fig 7-1: RB-DA6 Front Panel.
Fig 7-2: RB-DA6G Front Panel.
The RB-DA6 and RB-DA6G are high performance 6 way stereo analogue distribution
amplifiers for splitting a source to a number of different outputs. The RB-DA6 has 1 stereo
input and 6 stereo outputs with gain control on both inputs. It can also be configured so
that 1 mono input can be distributed to 12 outputs. As a variant of the RB-DA6, the RBDA6G, has an individual gain control on every output.
The XLR-3 inputs and outputs are electronically balanced and can be wired unbalanced.
Each output is individually buffered so that a short circuit on one won’t affect the others.
The outputs can be wired unbalanced.
The RB-DA6 has master left and right gain controls which are pre- set potentiometers
accessible through the front panel. On the RB-DA6G each channel has an individual output
gain control (normalising) which are all pre-set potentiometers, also accessible through
the front panel. The 1-12 mono, 1-6 stereo switch is recessed on the front panel to prevent
accidental knocking. An LED power indicator on the front panel displays the power supply
connection.
AUDIO DISTRIBUTION AMPLIFIERS - RB-DA6 & RB-DA6G
Page 37
Redbox User Handbook No 2
23
System Block Diagrams
Left Outputs
Balanced
Left Input
Balanced
Stereo/Mono
Right
Input
Balanced
Right Outputs
Balanced (Mono 7-12)
Gain
Gain
12345612 3456
Left Outputs
Balanced
Left Input
Balanced
Stereo/Mono
Right
Input
Balanced
Right Outputs
Balanced (Mono 7-12)
12345612 3456
Fig 7-3: RB-DA6 Block Diagram.
AUDIO DISTRIBUTION
AMPLIFIERS
7
AUDIO DISTRIBUTION AMPLIFIERS - RB-DA6 & RB-DA6G
Fig 7-4: RB-DA6G Block Diagram.
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Redbox User Handbook No 2
7
AUDIO DISTRIBUTION
AMPLIFIERS
Connections and Operation
Fig 7-5: RB-DA6 & RB-DA6G Rear Panel.
Inputs (Left and Right)
The XLR-3 input connectors can take balanced professional levels, or unbalanced by using
the front panel gain controls, and by connecting the non-phase to the signal ground. The
input can be configured as either a stereo input with six stereo outputs or a mono input
with twelve outputs. The XLR 3 pin input has the following connections:
Pin 1: Screen
Pin 2: Phase
Pin 3: Non-phase
Stereo Outputs 1-6 (Mono Outputs 1-12)
The XLR 3 pin outputs are electronically balanced, and can be wired unbalanced. Each
output is individually buffered so that a short circuit on one output will not affect the others.
They have the following connections:
Pin 1: Screen
Pin 2: Phase
Pin 3: Non-phase
Input Gain Control (RB-DA6)
The input gain on the RB-DA6 can be varied –8dB to 18db by adjusting the pre-set
potentiometers. These are accessible through the holes in the front panel. The RB-DA6 has
separate left and right master gain controls.
Stereo/
Input
Controls
Gain
Mono
Switch
Fig 7-6: RB-DA6 Front Panel.
Output Gain Control (RB-DA6G)
The output gain on the RB-DA6G can be varied –8dB to 18dB by adjusting the pre-set
potentiometers. These are accessible through the holes in the front panel. The RB-DA6G has
output gain controls on every output.
AUDIO DISTRIBUTION AMPLIFIERS - RB-DA6 & RB-DA6G
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Redbox User Handbook No 2
25
AUDIO DISTRIBUTION
AMPLIFIERS
Stereo/
Output Gain Controls
Fig 7-7: RB-DA6G Front Panel.
Stereo/Mono Operation
The mode of operation may be switched between a stereo distributed channel to 6 stereo
channels, and a mono channel to 12 mono channels, by the push button on the front panel,
which is recessed to prevent accidental switching.
Technical Specifications
Audio Specifications
Input Impedance >20kΩ bridging
Output Impedance <50Ω
Maximum Input Level +28dBu
Maximum Output Level +28dBu
Frequency Response 20Hz to 20kHz ± 0.1dB (600Ω load, ref 1kHz)
Gain Range Adjustable 8dB loss to 18dB gain
Common Mode Rejection >66dB typically
Distortion 0.01% THD @ 1kHz, ref +8dBu output
Noise -100dB unity gain ref +8dB (RB-DA6)
-88dB unity gain ref +8dB (RB-DA6G)
Connections
Inputs 2 x XLR 3 pin female (Balanced, can be unbalanced)
Outputs 12 x XLR 3 pin male (Balanced, can be unbalanced)
Mains Input Filtered IEC, 110V-120V, or 220-240V, fused, 6W maximum
Fuse Rating: Anti-surge fuse 100mA 20 x 5mm (230VAC)
Anti-surge fuse 250mA 20 x 5mm (115VAC)
Equipment Type
RB-DA6: 6 way stereo distribution amplifier
RB-DA6G: 6 way stereo distribution amplifier with output gain
Mono
Switch
7
AUDIO DISTRIBUTION AMPLIFIERS - RB-DA6 & RB-DA6G
Physical Specifications
Dimensions (Raw): 48cm (W ) x 10.8cm (D) x 4.2cm (H) (1U)
Dimensions (Boxed): 53cm (W) x 20.5cm (D) x 6cm (H)
Weight: Nett: 1.3kg Gross: 1.9kg
Page 40
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8
AUDIO DISTRIBUTION
AMPLIFIERS
8 RB-DA4x5 4 Input 4 x 5 Output Distribution Amplifier/Mixer
Introduction
Output
Gain
Controls
Fig 8-1: RB-DA4x5 Front Panel.
The RB-DA4x5 is a 1U rack-mount combined distribution amplifier and mixer. It has 4
mono analogue audio inputs on female XLR and 4 groups of 5 outputs on 15 way D-type
connectors. Each output group has a five way front-panel DIP switch assigned to it which is
used to select the input(s) to send to the output group. This enables each of the four inputs,
and a 1kHz 0dBu tone, to be mixed to the output group.
The inputs and outputs are electronically balanced and can be wired unbalanced. Each
input has adjustable gain using a preset potentiometer, providing a gain range of -8dB to
+18dB. Each output is individually buffered so that a short circuit on one output will not
affect the others. The output gain of each group can similarly be adjusted between -8dB and
+18dB using preset potentiometers.
The DIP switch settings and gain controls are recessed beneath a front-mounting screw-on
cover so that settings can not be accidentally altered, for secure applications. Four bright
front-panel signal present LEDs show the levels of either the inputs or the output groups by
pressing the AUDIO PRESENCE button. The LEDs will show green illumination from -12dBu
through to 0dBu, amber from 0dBu through to +6dBu and red for inputs and outputs at
+6dBu and over.
Input
Selectors
Input
Gain
Controls
Input/
Output
Levels
AUDIO DISTRIBUTION AMPLIFIERS - RB-DA4x5
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Redbox User Handbook No 2
27
System Block Diagram
Balanced XLR
Input 1
Gain
Balanced XLR
Input 2
Gain
Balanced XLR
Input 3
Gain
Balanced XLR
Input 4
Gain
Reference
To ne
Output 1
Switch Bank
Meter 2
Output
Gain
Output 1
Switch Bank
Meter 4
Output
Gain
Output 1
Switch Bank
Meter 1
Output
Gain
Output 1
Switch Bank
Meter 3
Output
Gain
Meter In 3
Meter Out 3
Meter 3
Meter In 1
Meter Out 1
Meter 1
Meter In 4
Meter Out 4
Meter 4
Meter In 2
Meter Out 2
Meter 2
Fig 8-2: RB-DA4x5 Block Diagram.
Rear Panel Connections and Operation
AUDIO DISTRIBUTION
AMPLIFIERS
8
AUDIO DISTRIBUTION AMPLIFIERS - RB-DA4x5
Inputs Outputs
Fig 8-3: RB-DA4x5 Rear Panel.
Audio Inputs 1-4
The XLR 3 pin sockets used for the audio inputs are electronically balanced and have
an impedance of 20kΩ bridging. They are routed to the switch matrix. Each XLR has the
following connections:
Pin 1: Screen
Pin 2: Phase
Pin 3: Non-phase
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Redbox User Handbook No 2
1 2 3 4 5 6 7 8 9
10
OUTPUT 1
TEST TONE
1 2 3 4
OUTPUT 2
TEST TONE
1 2 3 4
l
l
8
Output 1
Output 2 Output 4
Output 3 Output 5
AUDIO DISTRIBUTION AMPLIFIERS - RB-DA4x5
AUDIO DISTRIBUTION
AMPLIFIERS
D-Type Audio Output Groups 1-4
Each output group connector has 5xDA driven balanced audio outputs on a D-type
connector outputs each with an output impedance of <50Ω.
1 8
9 15
Fig 8-4: RB-DA4x5 Audio Output Group15-Way D-Type Plug.
Function Output 1 Output 2 Output 3 Output 4 Output 5
Out + Pin No. 1 3 4 6 7
Out - Pin No. 9 10 12 13 15
Signal Ground Pin No. 2 11 5 14 8
Fig 8-5: RB-DA4x5 Pinout for Audio Output Group Connector.
Monitor LEDs
There are 4 LEDs on the front panel that indicate the relative levels of the audio signals at
the inputs or outputs. A pushbutton switch on the front panel toggles the function of these
LEDs between input and output. These LEDs indicate the levels of the signals by illuminating
green for signals between –12 and 0dBu, illuminating yellow for signals between 0 and
+6dBu, and illuminating red for signals over +6dBu.
Input Level Adjustment
The gain for each input can be adjusted through pre-set potentiometers that are accessible
from behind the removable plate on the front panel. The gain of each balanced input is
variable within a range of -8dB to +18dB into the router input.
Output Level Adjustment
The gain for each output group can be adjusted through pre-set potentiometers that are
accessible from behind the removable plate on the front panel. The gain of each output
group is variable within a range of -8dB to +18dB from the router output.
Routing Selection
Each output group is capable of selecting its signal from any combination of inputs and the
test tone. Set the appropriate dip-switch for that group & that input to the on position to
include the signal in the group’s output.
On $
Fig 8-6: RB-DA4x5 Routing Selection Switch.
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Redbox User Handbook No 2
29
AUDIO DISTRIBUTION
AMPLIFIERS
8
Function
Input 1 SW1-1 On SW1-6 On SW2-1 On SW2-6 On
Input 2 SW1-2 On SW1-7 On SW2-2 On SW2-7 On
Input 3 SW1-3 On SW1-8 On SW2-3 On SW2-8 On
Input 4 SW1-4 On SW1-9 On SW2-4 On SW2-9 On
Test Tone SW1-5 On SW1-10 On SW2-5 On SW2-10 On
Fig 8-7: RB-DA4x5 Routing Selection Switch Functions.
Alignment Test Tone
Each of the output groups has the capability of selecting a 1kHz, 0dBu test tone. This signal
can be used as a reference to set the output gain levels. Once these values are known then
the input gains can be set by providing a known tone to the input and adjusting the input
gain to the required level. It is possible to use this test tone as a reference level for the input
gain by adjusting the output gains to unity and then looping back any output to the input
connector. The on-board oscillator is temperature sensitive and in cold conditions may take
a short time to start oscillating. In any case you should always allow the unit to fully come to
its normal operating temperature before adjusting the gains.
Group 1
Routing
Group 2
Routing
Group 3
Routing
Group 4
Routing
Technical Specifications
Audio Specifications
Maximum Input Level: +28dBu
Input Impedance (XLR): >20kΩ balanced bridging
Output Impedance: <50Ω
Maximum Output Level: +28dBu
Distortion: 0.01% THD @ 1kHz, ref +8dBu output
Noise: -100dB, unity gain, ref +8dBu output
Common Mode Rejection: >66dB typically
Frequency Response: 20Hz to 20kHz ±0.1dB (600Ω load, ref 1kHz)
Input Gain Range: Adjustable 8dB loss to 18dB gain (channel 1-4 adjust)
Output Gain Range: Adjustable 8dB loss to 18dB gain (group 1-4 adjust)
Connections
Inputs (4 x mono): 4 x XLR 3 pin female (Balanced)
Outputs (20 x mono): 4 x 15 way D-type (Balanced)
Mains Input: Filtered IEC, 110V-120V, or 220-240V switchable,
fused, 9W maximum
Fuse Rating: Anti-surge fuse 100mA 20 x 5mm (230VAC)
Anti-surge fuse 250mA 20 x 5mm (115VAC)
Equipment Type
RB-DA4x5: 4 input to 20 output distribution amplifier & mixer
AUDIO DISTRIBUTION AMPLIFIERS - RB-DA4x5
Physical Specifications
Dimensions (Raw): 48cm (W ) x 15.8cm (D*) x 4.2cm (H) (1U)
Dimensions (Boxed): 53cm (W) x 25.5cm (D*) x 6cm (H)
Weight: Nett: 1.6kg Gross: 2.2kg
* Note that this product is deeper than standard redboxes.
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Redbox User Handbook No 2
2
9
1
9
AUDIO DISTRIBUTION
AMPLIFIERS
9 RB-DDA6A 6 Way Stereo AES/EBU Digital Distribution Amplifier
and RB-DDA6S 6 Way Stereo S/PDIF Digital Distribution
Amplifier
Introduction
Fig 9-1: RB-DDA6A/S Front Panel.
The RB-DDA6A digital distribution amplifier is used for distributing digital
audio data in AES/EBU format, repeating both the audio data and the status
information of the input whilst re-normalising to standard digital audio levels.
It has a single XLR-3 female AES/EBU audio input which is distributed to 6 XLR-3 male
AES/EBU outputs.
Applications include distributing audio from a digital mixing desk to multiple digital
recorders, or feeding multiple studios with an output from a DAT machine.
It can accept input sample rates in the range of 30kHz - 100kHz, and bit rates of 16, 20 and
24 bit. So, it can be used for standard CD signal distribution at 16 bit 44.1kHz, as well as for
high quality 24 bit 96kHz recording.
The RB-DDA6S digital distribution amplifier is similar to the RB-DDA6A except that it is used
for distributing digital audio data in S/PDIF format.
It has a single S/PDIF audio input which is distributed to 6 x S/PDIF audio outputs at the
same level and condition as the input signal. It can accept input sample rates in the range of
30kHz - 100kHz, and bit rates of 16, 20 and 24 bit.
Uses include audio distribution at 16 bit 44.1kHz from a consumer CD player to multiple
digital recorders, distribution of high quality 24 bit 96kHz signals from digital mixing desks
to recorders and connection of the output of, say, a DVD player to multiple studios.
AUDIO DISTRIBUTION AMPLIFIERS-RB-DDA6A & RB-DDA6S
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Redbox User Handbook No 2
31
System Block Diagrams
AES/EBU
Transmitter
Output XLR-3
Male
Input XLR-3
Female
AES/EBU
Transmitter
Output XLR-3
Male
AES/EBU
Transmitter
Output XLR-3
Male
AES/EBU
Transmitter
Output XLR-3
Male
AES/EBU
Transmitter
Output XLR-3
Male
AES/EBU
Transmitter
Output XLR-3
Male
AES/EBU
Receiver
AUDIO DISTRIBUTION
AMPLIFIERS
9
AUDIO DISTRIBUTION AMPLIFIERS-RB-DDA6A & RB-DDA6S
Fig 9-2: RB-DDA6A System Block Diagram.
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Redbox User Handbook No 2
9
S/PDIF
Transmitter
Output
RCA Phono
Input
RCA Phono
S/PDIF
Transmitter
Output
RCA Phono
S/PDIF
Transmitter
Output
RCA Phono
S/PDIF
Transmitter
Output
RCA Phono
S/PDIF
Transmitter
Output
RCA Phono
S/PDIF
Transmitter
Output
RCA Phono
S/PDIF
Receiver
AUDIO DISTRIBUTION
AMPLIFIERS
Fig 9-3: RB-DDA6S System Block Diagram.
AUDIO DISTRIBUTION AMPLIFIERS-RB-DDA6A & RB-DDA6S
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Redbox User Handbook No 2
33
Rear Panel Connections and Operations
AES/EBU
Input
AES/EBU
Outputs
AUDIO DISTRIBUTION
AMPLIFIERS
9
Fig 9-4: RB-DDA6A Rear panel.
AES/EBU Input
The XLR 3 pin socket has an impedance of 110Ω. It has the following connections:
Pin 1: Screen
Pin 2: Phase
Pin 3: Non-phase
AES/EBU Outputs
The XLR 3 pin sockets have an impedance of 110Ω. They have the following connections:
Pin 1: Screen
Pin 2: Phase
Pin 3: Non-phase
S/PDIF
Input
Fig 9-5: RB-DDA6S Rear Panel.
S/PDIF Input
The S/PDIF phono input has an impedance of 75Ω.
S/PDIF Outputs
The S/PDIF phono outputs have an impedance of 75Ω.
S/PDIF
Outputs
AUDIO DISTRIBUTION AMPLIFIERS-RB-DDA6A & RB-DDA6S
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Redbox User Handbook No 2
9
AUDIO DISTRIBUTION
AMPLIFIERS
Technical Specifications
Audio Specifications
RB-DDA6A
Input Impedance: 110Ω ± 20% balanced
Output Impedance: 110Ω ± 20% balanced
Sample Freq Range: 30-100kHz (i.e. including 32kHz, 44.1kHz, 48kHz, 64kHz,
88.2kHz and 96kHz)
Signal Level: 3V/10V peak to peak min/max
RB-DDA6S
Input Impedance: 75Ω ±5% unbalanced
Output Impedance: 75Ω ±5% unbalanced
Sample Freq Range: 30-100kHz (i.e. including 32kHz, 44.1kHz, 48kHz, 64kHz,
88.2kHz and 96kHz)
Signal Level: Balanced min 0.5V ±20% peak to peak
Connections
RB-DDA6A
Input: 1 x AES/EBU XLR 3 pin female (balanced)
Outputs: 6 x AES/EBU XLR 3 pin male (balanced)
Mains Input Filtered IEC, 110-120V, or 220-240V switchable,
fused, 6W max
Fuse Rating: Anti-surge fuse 100mA 20 x 5mm (230VAC)
Anti-surge fuse 250mA 20 x 5mm (115VAC)
RB-DDA6S
Input (unbalanced): 1 x S/PDIF RCA phono female
Outputs: 6 x S/PDIF RCA phono female (unbalanced)
Mains Input: Filtered IEC, 110-120V, or 220-240V switchable,
fused, 6W max
Fuse Rating: Anti-surge fuse 100mA 20 x 5mm (230VAC)
Anti-surge fuse 250mA 20 x 5mm (115VAC)
Equipment Type
RB-DDA6A 6 way AES/EBU stereo digital distribution amplifier
RB-DDA6S 6 way stereo S/PDIF digital distribution amplifier
Physical Specifications
RB-DDA6A
Dimensions (Raw): 28cm (W ) x 10.8cm (D) x 4.2cm (H) (1U)
Dimensions (Boxed): 36cm (W) x 20.5cm (D) x 6cm (H)
Weight: Nett: 0.95kg Gross: 1.4kg
RB-DDA6S
Dimensions (Raw): 28cm (W ) x 10.8cm (D) x 4.2cm (H) (1U)
Dimensions (Boxed): 36cm (W) x 20.5cm (D) x 6cm (H)
Weight: Nett: 0.9kg Gross: 1.35kg
AUDIO DISTRIBUTION AMPLIFIERS-RB-DDA6A & RB-DDA6S
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Redbox User Handbook No 2
35
AUDIO DISTRIBUTION
AMPLIFIERS
10 RB-DDA6W 6 Way Word Clock Distribution Amplifier
Introduction
10
Fig 10-1: RB-DDA6W Front Panel.
The RB-DDA6W 6 Way Word Clock Distribution Amplifier distributes a word clock BNC input
signal to 6 word clock BNC outputs re-conditioned. It is used in distributing reference clocks
for digital audio systems.
It has a single female BNC input which is distributed to 6 female BNC outputs.
The unit’s primary application is to distribute a master TTL word clock source to multiple
pieces of equipment that need to be synchronised from the master.
AUDIO DISTRIBUTION AMPLIFIERS - RB-DDA6W
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Redbox User Handbook No 2
10
TTL
Transmitter
Output
BNC
Input
BNC
TTL
Transmitter
Output
BNC
TTL
Transmitter
Output
BNC
TTL
Transmitter
Output
BNC
TTL
Transmitter
Output
BNC
TTL
Transmitter
Output
BNC
TTL
Receiver
AUDIO DISTRIBUTION
AMPLIFIERS
System Block Diagram
Fig 10-2: RB-DDA6W System Block Diagram.
AUDIO DISTRIBUTION AMPLIFIERS - RB-DDA6W
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37
Rear Panel Connections and Operations
Word Clock
Input
Word Clock
Outputs
AUDIO DISTRIBUTION
AMPLIFIERS
10
Fig 10-3: RB-DDA6W Rear Panel.
Word Clock Input
The Word Clock BNC input has an impedance of 75 Ω.
Word Clock Outputs
The Word Clock BNC outputs have an impedance of <50 Ω.
Technical Specifications
Signal Specifications
Input Impedance 75Ω
Output Impedance <50Ω
Connections
Input 1 x BNC female
Outputs 6 x BNC female
Mains Input Filtered IEC, 110-120V, or 220-240V switchable,
fused, 6W max
Fuse Rating: Anti-surge fuse 100mA 20 x 5mm (230VAC)
Anti-surge fuse 250mA 20 x 5mm (115VAC)
Equipment Type
RB-DDA6W 6 way word clock distribution amplifier
Physical Specifications
Dimensions (Raw) 28cm (W) x 10.8cm (D) x 4.2cm (H) (1U)
Dimensions (Boxed) 36cm ( W) x 20.5cm (D) x 6cm (H)
Weight Nett: 0.9kg Gross: 1.35kg
AUDIO DISTRIBUTION AMPLIFIERS - RB-DDA6W
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Redbox User Handbook No 2
11
HE AD PH ON E DI ST RI BU TI ON
AMPLIFIERS
11 RB-HD1 Stereo Headphone Amplifier &
RB-HD2 Dual Headphone Amplifier
Introduction
Fig 11-1: RB-HD1 Front Panel.
The RB-HD1 is a 1U rack-mount stereo headphone amplifier for driving up to two pairs of
professional stereo headphones from a single stereo or mono input. One headphone socket
is on the front panel with one on the rear.
The main stereo input uses electronically balanced XLR-3 connectors on the rear panel,
which can be wired un-balanced. The output volume for the headphones can be controlled
either by a pot situated on the front panel or a VCA signal supplied externally via the remote
connector.
A mono input can be mixed into the main headphone feed, for example, for mixing in
talkback to the headphones. This has an input level control via a recessed adjustable
potentiometer. The mono mix input can also be controlled remotely.
A stereo/mono switch is recessed on the rear panel to prevent accidental knocking. With
mono selected, audio is sent to both left and right ear pieces. A LED power indicator on the
front panel displays the power supply connection.
Fig 11-2: RB-HD2 Front Panel.
The RB-HD2 is a high performance 2-way stereo headphone distribution amplifier for
driving up to 2 pairs of professional stereo headphones from a single stereo or mono input.
A switch on the rear panel enables the distribution of a mono signal to all four outputs (i.e.
both earpieces of a pair of stereo headphones) via the left channel input. The stereo/mono
switch is located on the rear panel to prevent accidental knocking.
The XLR-3 inputs are electronically balanced and can be wired unbalanced. There are two
pre-set controls on the rear panel that adjust the level of the master input signal to the
outputs.
Each output is on a ¼” stereo jack socket and is designed to drive 150mW into 32 ohm to
600 ohm stereo headphones. The outputs are individually buffered with their own front
panel volume control. A LED power indicator on the front panel displays the power supply
connection.
HEADPHONE DISTRIBUTION AMPLIFIERS-RB-HD1 & RB-HD2
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Redbox User Handbook No 2
39
System Block Diagrams
Left Input
Audio XLR
Audio Input
Amplifier
Stereo Jack
Output
Stereo Jack
Output
Audio Output
Amplifier
VCA
Right Input
Audio XLR
Push
Switch
Input
Mono
Mix
Stereo/Mono
Control Switch
Gain
Remote ConnectorVolume
Local/Remote
Control Switch
Audio Input
Amplifier
Stereo
Jack
Output
Stereo
Jack
Output
Audio
Output
Amp
Audio
Output
Amp
Master
Input
Stereo/Mono
Control Switch
Push
Switch
Stereo
Volume
Volume
XLR
Fig 11-3: RB-HD1 Block Diagram.
HE AD PH ON E DI ST RI BU TI ON
AMPLIFIERS
11
HEADPHONE DISTRIBUTION AMPLIFIERS-RB-HD1 & RB-HD2
Fig 11-4: RB-HD2 Block Diagram.
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Redbox User Handbook No 2
11
HE AD PH ON E DI ST RI BU TI ON
AMPLIFIERS
Front Panel Connections and Controls
Volume
Stereo
Output
Fig 11-5: RB-HD1 Front Panel Controls.
Stereo Outputs 1-2 (Mono Outputs1-2)
The outputs available on the front and rear panel through ¼” stereo jack sockets are pushpull, designed to drive 150 mW into 32Ω to 600Ω professional headphones. Each output is
individually buffered.
Volume Level Control
The volume level control sets the output level of the two stereo headphone sockets.
The two headphone outputs have a maximum output of +11dBu.
Level
Control
Stereo
Output
Fig 11-6: RB-HD2 Front Panel Controls.
Stereo Outputs 1-2 (Mono Outputs 1-2)
The outputs available on the front panel through ¼” stereo jack sockets are push-pull,
designed to drive 150 mW into 32Ω to 600Ω professional headphones. Each output is
individually buffered.
Channel Volume Controls
Each channel has its own volume control so that you have control of the signal volume to an
individual output from the master input.
Volume
Level
Control
Stereo
Output
Volume
Level
Control
HEADPHONE DISTRIBUTION AMPLIFIERS-RB-HD1 & RB-HD2
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41
HE AD PH ON E DI ST RI BU TI ON
Rear Panel Connections and Operation
AMPLIFIERS
11
Main
Stereo
Inputs
Stereo/ Mono
Switch
Fig 11-7: RB-HD1 Rear Panel.
Stereo Input Gain Adjustment
Fig 11-8: RB-HD2 Rear Panel.
Main Stereo Inputs (Left and Right)
The XLR-3 input connectors can take balanced professional levels, or unbalanced by using
the volume control to increase the input level, and by connecting the non-phase to the
signal ground. The input can be configured as either a stereo input with two stereo outputs
or a mono input with two mono paired outputs. The XLR 3 pin input has the following
connections:
Pin 1: Screen
Pin 2: Phase
Pin 3: Non-phase
Stereo Input Gain Adjustment (RB-HD1)
There are two preset controls on the rear panel that adjust the level of the master input
signal to the outputs from -12dB to +20dB gain.
Mono
Mix
Input
Mono Mix Input
Gain Adjustment
Main Stereo
Inputs
Headphone
Stereo/
Mono Switch
Remote
Connector
Local/ Remote
Control Switch
HEADPHONE DISTRIBUTION AMPLIFIERS-RB-HD1 & RB-HD2
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Redbox User Handbook No 2
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HE AD PH ON E DI ST RI BU TI ON
AMPLIFIERS
Stereo/Mono Operation
The mode of operation may be switched between a stereo distributed channel to 2 stereo
channels, or a mono channel to two mono paired outputs (i.e. the same signal to both
ear pieces) by using the push button, mounted on the rear panel to prevent accidental
switching.
Mono Mix Input (RB-HD1)
The XLR-3 input connector can take balanced professional levels, or unbalanced by
connecting the non-phase to the signal ground. This input is used for mixing with the main
stereo input, which is controlled by the MIX_EN pin (pin 8 on the remote connector) on
the remote connector. While this signal is shorted to the ground pin (pin 9 on the remote
connector) mixing is enabled and is only disabled once the signal from MIX_EN to pin 9 is
open on the remote connector. The XLR 3 pin input has the following connections:
Pin 1: Screen
Pin 2: Phase
Pin 3: Non-phase
Mono Mix Input Gain Adjustment (RB-HD1)
A rotary pre-set potentiometer can be used to adjust the gain of the mono mix input by
22dBu.
Local/Remote Control Operation (RB-HD1)
The level to the two outputs can be controlled in one of two ways, either locally, by the pot
situated on the front panel or remotely, by a VCA signal supplied externally to the remote
connector.
Remote Connector (RB-HD1)
The remote connector is a 9-pin D-type socket, which is situated on the rear panel. It has
connections as shown below.
Pin No. Signal I/O Description
Pin 1 Pot wiper I Volume control signal
Pin 2 Pot top O +5V
Pin 3 N/C - No connection
Pin 4 N/C - No connection
Pin 5 N/C - No connection
Pin 6 Pot bottom - Ground
Pin 7 N/C - No connection
Pin 8 MIX_EN I Make to pin 9
Pin 9 0V - Ground
Fig 11-9: RB-HD1 Remote Connector
HEADPHONE DISTRIBUTION AMPLIFIERS-RB-HD1 & RB-HD2
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HE AD PH ON E DI ST RI BU TI ON
AMPLIFIERS
Technical Specifications
Audio Specifications RB-HD1 & RB-HD2:
Maximum Input Level: +28dBu
Input Impedance: >20kΩ balanced bridging (main)
Input Gain Range: -12dB to +20dB (pre-set pots) (RB-HD2)
Output Level: Drives 150 mW into 32Ω to 600Ω headphones
Volume Control: -80dB to +11dB gain
Mono Mix Input Gain Range: 22dBu (RB-HD1)
Connections
RB-HD1:
Main Stereo Input: 2 x XLR 3 pin female (Balanced, can be wired unbalanced)
Mono Mix Input: 1 x XLR 3 pin female (Balanced, can be wired unbalanced)
Outputs: 2 x ¼” (6.35mm) A/B gauge 3-pole stereo jack sockets
Remote Control: 9-pin D-type socket
Mains Input: Filtered IEC, 110V-120V, or 220-240V switchable, fused,
9W maximum
Fuse Rating: Anti-surge fuse 100mA 20 x 5mm (230VAC)
Anti-surge fuse 250mA 20 x 5mm (115VAC)
RB-HD2:
Main Stereo Input 2 x XLR 3 pin female (Balanced, can be wired unbalanced)
Outputs 2 x ¼” (6.35mm) A/B gauge 3-pole stereo jack sockets
Mains Input Filtered IEC, 110V-120V, or 220-240V, fused, switchable,
9W maximum
Fuse Rating: Anti-surge fuse 100mA 20 x 5mm (230VAC)
Anti-surge fuse 250mA 20 x 5mm (115VAC)
Equipment Type
RB-HD1: Stereo headphone amplifier
RB-HD2: Dual stereo headphone amplifier
11
HEADPHONE DISTRIBUTION AMPLIFIERS-RB-HD1 & RB-HD2
Physical Specifications
RB-HD1:
Dimensions (Raw): 48cm (W ) x 10.8cm (D) x 4.2cm (H) (1U)
Dimensions (Boxed): 53cm (W) x 20.5cm (D) x 6cm
Weight: Nett: 1.35kg Gross: 2.0kg
RB-HD2:
Dimensions (Raw): 48cm (W ) x 10.8cm (D) x 4.2cm (H) (1U)
Dimensions (Boxed): 53cm (W) x 20.5cm (D) x 6cm
Weight: Nett: 1.35kg Gross: 2.0kg
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Redbox User Handbook No 2
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HE AD PH ON E DI ST RI BU TI ON
AMPLIFIERS
12 RB-HD6 6 Way Headphone Distribution Amplifier
Introduction
Fig 12-1: RB-HD6 Front Panel.
The RB-HD6 is a high performance 6-way stereo headphone distribution amplifier for
driving up to 6 pairs of professional stereo headphones from a single stereo or mono input.
A switch on the rear panel enables the distribution of a mono signal to all twelve outputs
(i.e. both earpieces of a pair of stereo headphones) via the left channel input.
Alternatively, the RB-HD6 can be used as six separate stereo headphone amplifiers by
using the override (insert-point, or break-jack) input associated with each outlet. A typical
application might be to provide common headphone feeds for guests around a table in a
radio studio, with a separately derived feed, perhaps including talkback, for the presenter.
The over-ride inputs can also be configured as parallel outputs (to the front outputs) by
altering jumper settings inside the unit.
The XLR-3 inputs are electronically balanced and can be wired unbalanced. There is a master
control that adjusts the level of the master signal to all the outputs. This master control can
be disabled by the use of internal jumpers. Each output is designed to drive 150 mW into
32Ω to 600Ω stereo headphones and is individually buffered with its own volume control.
The input level and output volume controls are all potentiometers on the front panel.
The stereo/mono switch is recessed on the rear panel to prevent accidental knocking.
A LED power indicator on the front panel displays the power supply connection.
HEADPHONE DISTRIBUTION AMPLIFIERS - RB-HD6
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12
System Block Diagram
HE AD PH ON E DI ST RI BU TI ON
AMPLIFIERS
HEADPHONE DISTRIBUTION AMPLIFIERS - RB-HD6
Fig 12-2: RB-HD6 Block Diagram.
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Redbox User Handbook No 2
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HEADPHONE DISTRIBUTION AMPLIFIERS - RB-HD6
HE AD PH ON E DI ST RI BU TI ON
AMPLIFIERS
Rear Panel Connections and Operation
Stereo
Inputs
Stereo/
Mono
Operation
Fig 12-3: RB-HD6 Rear Panel.
Stereo Input (Left and Right)
The XLR-3 input connectors can take balanced professional levels, or unbalanced by using
the front panel master control to increase the input level, and by connecting the nonphase to the signal ground. The input can be configured as either a stereo input with six
stereo outputs or a mono input with six mono paired outputs. The XLR 3 pin input has the
following connections:
Pin 1: Screen
Pin 2: Phase
Pin 3: Non-phase
Stereo/Mono Operation
The mode of operation may be switched between a stereo distributed channel to 6 stereo
channels, or a mono channel to six mono paired outputs (i.e. the same signal to both ear
pieces), by the push button on the rear panel which is recessed to prevent accidental
switching.
Channel Insertion Inputs/Parallel Outputs
Each channel has an unbalanced override/insertion input via a ¼” stereo audio jack socket
on the rear panel, which overrides the master input.
Each connector can also be individually configured as a parallel output providing the same
signal as the output on the front of the unit. To configure the jack connector as an output,
you’ll need to alter some jumper settings inside the unit.
Removing the Equipment Covers
To get inside the RB-HD6, first ensure that it has been disconnected from the mains power
and that the mains IEC lead to the unit has been removed. Observing anti-static precautions,
undo the four cross-head screws on the back panel at the far left and far right of the panel
(2 at each end). Also undo the small brass screws which hold the top and bottom panels to
the rear panel. The rear panel should slide backwards out of the unit together with the main
circuit board.
Channel Insertion Inputs
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12
HE AD PH ON E DI ST RI BU TI ON
AMPLIFIERS
Configuring Insert Inputs/Parallel Outputs
On the main circuit board, you’ll see some jumpers (small black rectangles), the position of
which will define whether a particular jack socket operates as an input or output.
The drawings below show the different jumper settings available. Each input/output can
be configured individually, so you could have three jacks set as inputs and three as outputs
if needed.
Input/Output 1 2 3 4 5 6
Jumpers
to Alter
Fig 12-4: RB-HD6 Jumper Assignments.
Fig 12-5: RB-HD6 Jumper Positions.
Once you’ve set up the jumpers, slide the circuit board back into the Redbox housing using
the slots along the inside edge of the metalwork as a guide. Replace the screws on the top,
bottom and rear panels of the RB-HD6.
Important Note : The screws provide earthing protection to the chassis and grounding
protection for CE approval – it is important that you reinsert all the screws provided.
Left JP1 & 2 JP5 & 6 JP9 & 10 JP13 & 14 JP17 & 18 JP21 & 22
Right JP3 & 4 JP7 & 8 JP11 & 12 JP15 & 16 JP19 & 20 JP23 & 24
HEADPHONE DISTRIBUTION AMPLIFIERS - RB-HD6
Front Panel Connections and Controls
Volume
Controls
Headphone Outputs
Fig 12-6: RB-HD6 Front Panel Controls.
Stereo Outputs 1-6 (Mono Outputs 1-6)
The outputs available on the front panel through ¼” stereo jack sockets are push-pull,
designed to drive 150 mW into 32Ω to 600Ω professional headphones. Each output is
individually buffered.
Master
Volume Control
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AMPLIFIERS
Master Level Control
The master level control will set the maximum level of all channels and will need to be
set high if an unbalanced consumer input level (-10dbu) is used. This level control can
be disabled by setting jumpers within the unit. See Page 46 for details on removing
the equipment covers. The two jumpers JP25 and JP26 can be found near the volume
potentiometer VR1 :
Jumper JP25 JP26
Enable Master Level Control On On
Disable Master Level Control Off Off
Fig 12-7: RB-HD6 Master Level Control.
Channel Volume Controls
Each channel has its own volume control so that you have control of the signal volume to an
individual output whether it is from the master input or the override input.
Technical Specifications
Audio Specifications
Input Impedance: >20kΩ balanced bridging (main),
>10kΩ unbalanced (insert points)
Maximum Input Level: +28dBu
Output Level: Drives 150 mW into 32Ω to 600Ω headphones
Override Inputs: +3dBu for full volume at +18dB gain
Individual Volume Control: -60dB to +18dB gain
Master Volume Control: ±10dB gain
Connections
Main Stereo Inputs: 2 x XLR 3 pin female (Balanced, can be wired unbalanced)
Insert Inputs & 6 x ¼” (6.35mm) A-gauge 3-pole stereo jack sockets
Parallel Outputs: (unbalanced, jumper configured)
Outputs: 6 x ¼” (6.35mm) A-gauge 3-pole stereo jack sockets
Mains Input: Filtered IEC, 110V-120V, or 220-240V switchable, fused,
9W maximum
Fuse Rating: Anti-surge fuse 100mA 20 x 5mm (230VAC)
Anti-surge fuse 250mA 20 x 5mm (115VAC)
Equipment Type
RB-HD6: 6 way stereo headphone distribution amplifier
48
Physical Specifications
HEADPHONE DISTRIBUTION AMPLIFIERS - RB-HD6
Dimensions (Raw): 48cm (W ) x 10.8cm (D) x 4.2cm (H) (1U)
Dimensions (Boxed): 53cm (W) x 20.5cm (D) x 6cm (H)
Weight: Nett: 1.35kg Gross: 2.0kg
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AUDIO DISTRIBUTION
AES/EBU Volume
Control
Stereo Jack
Output
X6
S/PDIF
Digital
Input
Audio
Output
Amp
AES
Receiver
DAC
AMPLIFIERS
13 RB-DHD6 Digital 6 Way Headphone Distribution Amplifier
Introduction
Fig 13-1: RB-DHD6 Front Panel.
The RB-DHD6 digital 6 way headphone distribution amplifier is a 1U rackmount which receives a digital input signal, as either AES/EBU or S/PDIF and
converts it to 6 individually buffered, jack-plug, headphone outputs, each with
their own volume control.
Useful for connection to digital mixing desks, digital routers and matrices, the RB-DHD6
connects directly to an AES/EBU or S/PDIF output to provide the highest quality audio
directly to the headphones. The input connectors consist of a single balanced XLR-3 for the
AES/EBU input and a single unbalanced phono connector for the S/PDIF input.
A button located on the rear panel is used to select either the AES/EBU, or S/PDIF, input and
de-emphasis on the output can be controlled via dipswitch. If de-emphasis is selected, the
RB-DHD6 will decode 50/15µs emphasis when indicated by certain channel status bits in the
incoming digital audio data.
When operating, the front panel power LED flashes red and amber whenever the unit is not
synchronised to the incoming digital signal.
13
AUDIO DISTRIBUTION AMPLIFIERS - RB-DHD6
System Block Diagram
Fig 13-2: RB-DHD6 System Block Diagram.
Front Panel Indicators & Controls
Sync & Power LED
Fig 13-3: RB-DHD6 Front Panel Controls.
Redbox User Handbook No 2
Headphone Outputs
Volume
Controls
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AUDIO DISTRIBUTION
AMPLIFIERS
Sync & Power Indicator
The LED on the front panel is normally red to indicate that power is present on the unit.
However, it also has a secondary role to indicate the status of the digital inputs
Flashing between red and amber – indicates a loss of a valid digital input signal.
Headphone Outputs
The headphone outputs on the front panel consist of six ¼” stereo jack sockets, designed to
drive 150 mW into 32Ω to 600Ω professional headphones.
Volume Control
The headphone outputs each have their own volume control and have a maximum output
level of +12dBu.
Rear Panel Connections and Operation
Fig 13-4: RB-DHD6 Rear Panel.
AES/EBU Input
The digital input XLR 3 pin socket has an impedance of 110Ω. It has the following
connections:
Pin 1: Screen
Pin 2: Phase
Pin 3: Non-phase
The signals on this connector should meet the IEC 60968 specification
S/PDIF Input
The S/PDIF digital phono input has an impedance of 75Ω.
Status Select Switches
AUDIO DISTRIBUTION AMPLIFIERS - RB-DHD6
Status
1 On De-emphasis On
1 Off De-emphasis Off
2 Reserved
3 Reserved
4 Reserved
Fig 13-5: RB-DHD6 Status Select Switches.
Status
Select
Switches
AES/EBU
Input
Digital
Input
Select
S/PDIF
Input
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HE AD PH ON E DI ST RI BU TI ON
AMPLIFIERS
If de-emphasis is ‘on’ (switch 1) the RB-DHD6 will decode 50/15µs emphasis when indicated
by certain channel status bits in the incoming digital audio data. When ‘off’, no de-emphasis
is applied. The switch is ‘on’ when it is down.
Digital Input Select Button
This button is used to switch the digital input between the AES/EBU XLR connector (button
out) and the S/PDIF phono connector (button in).
Technical Specifications
Audio Specification
Input Impedance: 110Ω ± 20% AES/EBU
75Ω ±5% S/PDIF
Sample Freq. Range: 30kHz – 100kHz
Dynamic Range: >100dB
Headphones: Drives 150 mW into 32Ω to 600Ω headphones
Max Output Level: +12dBu
Headphone Gain Range: -80dBu to +12dBu
Connections
Digital Inputs: 1 x AES/EBU XLR 3 pin female
1 x S/PDIF RCA phono
Headphone Outputs: 6 x ¼” (6.35mm) A/B gauge 3-pole stereo jack sockets
Mains Input: Filtered IEC, 110-120V, or 220-240V switchable,
fused 10W max
Fuse Rating: Anti-surge fuse 100mA 20 x 5mm (230VAC)
Anti-surge fuse 250mA 20 x 5mm (115VAC)
Operational Controls
Digital Input Select: AES/EBU or S/PDIF, via push-switch
De-emphasis: DIP switch
Equipment Type
RB-DHD6 Digital 6 way stereo headphone distribution amplifier
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AUDIO DISTRIBUTION AMPLIFIERS - RB-DHD6
Physical Specifications
Dimensions (Raw) 48cm (W) x 10.8cm (D) x 4.2cm (H) (1U)
Dimensions (Boxed) 53cm (W ) x 20.5cm (D) x 6cm (H)
Weight Nett: 1.6kg Gross: 2.2kg
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14
CONNECTORS & CABLING
14 Connectors & Cabling
Many of the problems associated with installing and maintaining studio equipment are due
to the use of poor cables or faulty connections. It is recommended that, wherever possible,
pre-wired cables are purchased from recommended manufacturers. If you need bespoke
cables making, please ensure that a qualified engineer carries out the work.
The main types of connectors used with the Redboxes are the following:
XLR 3 Pin Connectors
The following diagram shows the pin details for the 3 pin XLR sockets and plugs:
Male Female
Pin 2
Phase Signal (Hot)
Pin 1
Screen Signal
Pin 3
Non Phase Signal (Cold)
Fig 14-1: XLR Connectors.
RCA Phono Connectors
The following diagram shows the connection details for the RCA phono connectors:
Pin 2
Phase Signal (Hot)
Pin 1
Screen Signal
Pin 3
Non Phase Signal (Cold)
CONNECTORS & CABLING
52
Ground
Fig 14-2: RCA Phono Connector.
Signal
¼” Jack Connector
The following diagram shows the connection details for the jack connector:
¼” ‘A’ Gauge Stereo Jack Plug
(In Phase) Tip-Hot Signal
(Non Phase) Ring-Cold Signal
Sleeve-Ground (Screen) Signal
¼” ‘A’ Gauge Stereo Jack Plug
Used For Headphones
Tip-Left Signal
Ring-Right Signal
Sleeve-Ground (Screen) Signal
Fig 14-3: ¼” Jack Connector.
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CONNECTORS & CABLING
D-Type Connectors
The following diagram shows the connection details for the D-type connectors as viewed
from the rear of a Redbox :
14
Pin 1
Pin 14
Fig 14-4: 25 Way D-Type Connectors.
Pin 1
Pin 10
Fig 14-5: 15 Way D-Type Connectors.
Pin 1
Pin 6
Fig 14-6: 9 Way D-Type Connectors.
Male Pin 13
Male Pin 9
Male Pin 5
Pin 13
Pin 25
Pin 9
Pin 15
Pin 5
Pin 9
Pin 25
Pin 15
Pin 9
Female
Female
Female
Pin 1
Pin 14
CONNECTORS & CABLING
Pin 1
Pin 10
Pin 1
Pin 6
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15
GLOSSARY
GLOSSARY
15 Glossary
1kHz 1000Hz or 1 kilohertz tone of 1kHz is often used for line-up and testing.
ADSL Asynchronous Digital Subscriber Link - a broadband delivery system over
standard telephone lines (between the exchange and the user).
AES Audio Engineering Society.
AES/EBU Professional digital audio standard covering frame format, connections
and interfaces. Interface is usually on XLR sockets and plugs.
AM Amplitude Modulation - older analogue modulation standard used on
long, medium and short wave.
APT-X Data reduction process for reducing the amount ofstorage or bit-rate
need for audio.
ATRAC Adaptive Transform Acoustic Coding - the data reduction of compression
scheme used in Mini-disk machines.
Attenuation The reduction of a signal level. Attenuation is usually measured in dB.
B-Channel Bearer Channel - the main carrier channels used in ISDN.
Balance The relative levels of the left and right channels of a stereo signal.
Balanced A way of sending audio over cable that protects it from induced
Audio interference.
CAR See racks room.
CAT 5 Category 5 - type of cabling/connectivity standards used in
computer networking.
CD Compact Disc.
Cleanfeed A cleanfeed is a signal produced by a telco module on a mixer which is
used as the output to be fed back to a caller on a telephone line.
The cleanfeed is a sum of all the other signals which constitute the
programme output, except for the caller’s audio. A cleanfeed signal will
generally be of a better quality than a mix-minus signal.
Clipping The onset of severe distortion in the signal path, usually caused by the
peak signal voltage being limited.
CMRR Common Mode Rejection Ratio. This is the ratio of the extent to which a
differential amplifier will cancel noise, which is present on both inputs,
compared to its ability to amplify the signal.
CODEC COder-DECoder - used to change a signal from one format to another
and back again.
Codecs Using digital circuits being offered by telecom providers, usually ISDN
(Integrated Services Data Networks) or other data transfer methods,
audio can be transferred with good to excellent quality over what almost
amount to dial-up telephone lines. The units operate by Coding the
audio into a digital data stream that can be transferred over the digital
circuit which is Decoded at the receiving end (Thus CoDec).
By using single or multiple circuits, very high quality audio can be
transferred from one place to another, even internationally.
Cross-talk This is the amount of a signal from a bus which appears, or is induced,
on a different signal. The problem is usually most prevalent with
adjacent channels.
DA Distribution Amplifier.
DAB Digital Audio Broadcasting = now called Digital Radio.
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GLOSSARY
DAT Digital Audio Tape.
dB (decibel) A ratio of two voltages or signal levels, expressed by the equation
dB=20LOG(V1/V2)
Adding the suffix “u” denotes that the signal is relative to 0.775V RMS.
Adding the suffix “v” denotes that the signal is relative to 1V RMS.
DCF This is radio code signal sourced from Mainflingen, near Frankfurt in
Germany, which can be used to automatically synchronize the
Sentinel+ audio logger and PC time to an accurate atomic clock,
European Time.
DDS & DDS and DDS-2 are world-wide standards established by Sony and
DDS-2 Hewlett-Packard which introduce many levels of error checking as data
is written to a DAT tape. DDS(-2) drives and tapes are used in security
products all over the world. 120m DDS-2 DAT tapes are more accurate
and reliable than DDS tapes and are able to store twice as much
audio data.
DI Direct Inject - a means of driving audio, usually from an instrument such
as a guitar, to allow the audio signal to be fed directly into a sound
desk input.
DLS Dynamic Label segment - a text message scheme used in digital radio,
usually to carry information about the programme. Like the radio-text
scheme used in RDS.
DSP Digital Signal Processing.
EBU European Broadcasting Union.
EIN Equivalent input noise. It is the ratio of output noise to the gain. It
describes the level of noise which would need to be fed into an ideal
amplifier to produce the measured output noise.
ENG (Electronic news gathering). Machines that can record audio and
video information digitally.
EON (RDS) Enhance Other Networks - a scheme for switching a listener’s radio
to another Effective Radiated Power.
EQ (Equalisation). This is a method of cutting or boosting selected bands of
frequencies in a signal.
FM Frequency Modulation - a way of sending audio or data over a radio
carrier, the 88 - 108 Broadcast Band is often known as the FM Band.
FSD Full Scale Digits - This is the analogue representation of the maximum
digital value that the converter in question can see before digital
clipping occurs.
3G Third generation mobile telephone system that may allow broadband
transmission of Global Positioning System.
Gain The degree of amplification, or attenuation, applied to a signal.
GRAM Gramophone Reproducer - a turntable with a ‘pick-up’ amplifier and
remote start interface.
HDLC High Speed Data Link.
Hybrid See TBU
IEC International Elecrotechnical Commision - often used to refer to a mains
connectivity standard, i.e. A type of plug/socket similar to that of a kettle,
used on most pro-audio equipment.
ISDN Integrated Services Digital Network - a system for sending high bandwidth
material over standard telephone lines.
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GLOSSARY
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GLOSSARY
kbps Kilo-bits per second - the number of 1s or 0s transmitted or transferred in
one second.
kHz Kilo Hertz (samples per second).
LAN Local Area Network - scheme where several computers on the same
premises are connected together so that they can exchange data.
LCD Liquid Crystal Display (grey displays e.g. on calculators).
LED Light Emitting Diode (small lights e.g. on computers).
LNB Low Noise Block - the RF amplifier attached to a satellite dish.
MCR See racks room.
MDU Mains Distribution Unit - a panel of mains outlets for power distribution.
MF Medium Frequency - another name for Medium Wave - roughly
frequencies between 300kHz and 3MHz.
MHz Mega-hertz - One million cycles per second.
Mix-minus A mix-minus is similar to a cleanfeed except that the caller’s voice is
removed from the signal electronically. Due to phasing problems at the
signal band edges, the mix-minus method often produces a lower
grade signal.
Mono Monophonic sound (system of broadcasting, recording or reproducing
GLOSSARY
sound) using only one channel between source and loudspeaker.
MP3 MPEG 1 Layer 3 - see MPEG.
MPEG (ISO MPEG) Motion Picture Experts Group. For audio, this is used to refer
to a framing format standard. There are several layers and variants. Most
common ones are listed below.
MPEG 1 Layer 1 Used for Digital Compact Cassette.
MPEG 1 Layer 2 (Musicam) used in digital radio, digital terrestrial
television, ISDN and many hard-disk storage systems.
MPEG 1 Layer 3 Known as MP3. A more elaborate version of
MPEG 1 Layer 2 that allows for audio storage using low bit-rates.
MSF This is radio code signal sourced from Rugby in England, which can be
used to automatically synchronize the Sentinel+ audio logger and PC
time to an accurate atomic clock, UK Time.
Musicam Masking Pattern Universal Sub-Band Encoding.
MUX Short for Multiplex - a ‘package’ of digital radio services.
Pan This controls the levels sent to the left and right outputs and is an
abbreviation of ‘panorama’.
PFL (Pre Fade Listen, or Cue). This is a method of auditioning audio material
independently of the programme output, without routing the signal
to air. The PFL button on each channel routes the signal to the PFL bus,
where it can be monitored.
PI Code (RDS) Programme Information Code used to identify an FM RDS station.
PPM Peak Performance Meter (BBC Specification).
Promo Something used to promote a product.
PS Name Programme Service Name - 8 characters used for naming an
(RDS) FM RDS station.
PSU Power Supply Unit.
PTY (RDS and DAB) Programme Type. A code transmitted to describe the
overall programme content of a radio station (Static PTY) and/or the
moment by moment content (Dynamic PTY). RDS has 32 codes although
3 are used in special circumstances only.
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GLOSSARY
Racks Room Often called the Master Control Room (MCR) or Central Apparatus Room
(CAR), the racks room is an engineering area containing studio routing
to transmitter equipment. Outside sources, phone-in equipment, off-air
and transmitter status monitoring and logging equipment (or the
transmitter itself !) are stored here with limited access.
RDS Radio Data System.
Reverb An echo (in very basic terms).
RF Radio Frequency.
RJ-45 A connection standard used in computer networking.
S/PDIF Sony/Phillips Digital Interface. Domestic digital audio interface standard
using phono connectors or optically using fibre-optic connectors.
SPL Sound Pressure Level.
TA Traffic Announcement (flag) - a means of signalling to a radio with FM
RDS indicating that traffic/travel news is being broadcast.
T/B Talk-back (and reverse talk-back). This is the ability for two or more
studios to communicate with each other off-air.
TBU See Telephone Balance Unit
TCP/IP Transmission Control Protocol / Internet Protocol. Computer
interconnection methodology used on the internet and LANs.
Telephone Telephone hybrids provide the interface between professional audio
Balance equipment and the public telephone network. They provide protection
Unit (TBU) for your equipment and the public telephone lines, allowing for varying
or Hybrid line signals and line conditions. Automatically cancelling out the
unwanted signal they also facilitate two-way communication down a
single telephone line. In most European countries, including the UK, the
TBU must be approved for connection to telephone company lines. Sonifex
TBU’s carry British Telecom and pan European approval.
THD The Total Harmonic Distortion is the percentage presence of signals
outside the measured reference frequency.
TMC (RDS) Traffic Message Channel.
TP Traffic Programme (flag) - a means of indicating to an RDS radio that a
station will carry traffic announcements.
U A height measurement for rack-mount equipment:
1U = 1.75 inches
2U = 3.5 inches
3U = 5.25 inches
4U = 7 inches
UPS Uninterruptible Power Supply. A device which maintains power to
equipment when the electricity supply fails.
VHF Very High Frequency - frequencies between 30MHz and 300MHz.
VP Vertical Polarisation i.e. of FM radio transmission.
VSWR Voltage Standing Wave Radio
VU Voltage units
WAP Wireless Application Protocol - a system for delivering mini-web pages to
mobile phones from the Internet.
X21 A data communications protocol used in synchronous connections.
XLR Professional, robust lockable audio connector - sometimes known as a
‘Cannon’ after one of the earlier manufacturers.
GLOSSARY
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