dbx 286s User Manual

286

®

Mic Preamp/Processor

Professional Audio Equipment

User Manual

IMPORTANT SAFETY INFORMATION

The symbols shown above are internationally accepted symbols that warn of potential
hazards with electrical products. The lightning flash with arrowpoint in an equilateral triangle
means that there are dangerous voltages present within the unit. The exclamation point
in an equilateral triangle indicates that it is necessary for the user to refer to the owner’s
manual.

These symbols warn that there are no user serviceable parts inside the unit. Do not open the
unit. Do not attempt to service the unit yourself. Refer all servicing to qualified personnel.
Opening the chassis for any reason will void the manufacturer’s warranty. Do not get the
unit wet. If liquid is spilled on the unit, shut it off immediately and take it to a dealer for
service. Disconnect the unit during storms to prevent damage.

Safety InStructIonS

NOTICE FOR CUSTOMERS IF YOUR UNIT IS EQUIPPED WITH A POWER CORD.

WARNING: THIS APPLIANCE SHALL BE CONNECTED TO A MAINS SOCKET OUTLET WITH A PROTECTIVE EARTHING
CONNECTION.

The cores in the mains lead are coloured in accordance with the following code:

GREEN and YELLOW - Earth BLUE - Neutral BROWN - Live

As colours of the cores in the mains lead of this appliance may not correspond with the coloured markings
identifying the terminals in your plug, proceed as follows:

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WARNING FOR YOUR PROTECTION

READ THE FOLLOWING:

KEEP THESE INSTRUCTIONS

HEED ALL WARNINGS

FOLLOW ALL INSTRUCTIONS

THE APPARATUS SHALL NOT BE EXPOSED TO DRIPPING OR
SPLASHING LIQUID AND NO OBJECT FILLED WITHI LIQUID,
SUCH AS VASES, SHALL BE PLACED ON THE APPARATUS.

CLEAN ONLY WITH A DRY CLOTH.

DO NOT BLOCK ANY OF THE VENTILATION OPENINGS.
INSTALL IN ACCORDANCE WITH THE MANUFACTURER’S
INSTRUCTIONS.

DO NOT INSTALL NEAR ANY HEAT SOURCES SUCH AS RA­DIATORS, HEAT REGISTERS, STOVES, OR OTHER APPARATUS
(INCLUDING AMPLIFIERS) THAT PRODUCE HEAT.

ONLY USE ATTACHMENTS/ACCESSORIES SPECIFIED BY THE
MANUFACTURER.

UNPLUG THIS APPARATUS DURING LIGHTNING STORMS OR
WHEN UNUSED FOR LONG PERIODS OF TIME.

Do not defeat the safety purpose of the polarized or grounding­type plug. A polarized plug has two blades with one wider than the
other. A grounding type plug has two blades and a third grounding
prong. The wide blade or third prong are provided for your safety.
If the provided plug does not fit your outlet, consult an electrician
for replacement of the obsolete outlet.

Protect the power cord from being walked on or pinched particu­larly at plugs, convenience receptacles, and the point where they
exit from the apparatus.

Use only with the cart stand, tripod bracket, or table specified by
the manufacture, or sold with the apparatus. When a cart is used,
use caution when moving the cart/apparatus combination to avoid
injury from tip-over.

•

The core which is coloured green and yellow must be connected to the terminal in the plug marked with the

letter E, or with the earth symbol, or coloured green, or green and yellow.

•

The core which is coloured blue must be connected to the terminal marked N or coloured black.

•

The core which is coloured brown must be connected to the terminal marked L or coloured red.

This equipment may require the use of a different line cord, attachment plug, or both, depending on the
available power source at installation. If the attachment plug needs to be changed, refer servicing to qualified
service personnel who should refer to the table below. The green/yellow wire shall be connected directly to
the units chassis.

CONDUCTOR

L LIVE BROWN BLACK

N NEUTRAL BLUE WHITE

E EARTH GND

WIRE COLOR

Normal Alt

GREEN/

YEL

GREEN

WARNING: If the ground is defeated, certain fault conditions in the unit or in the system to which it is connected
can result in full line voltage between chassis and earth ground. Severe injury or death can then result if the
chassis and earth ground are touched simultaneously.

If you want to dispose this product, do not mix it with general household waste. There is a
separate collection system for used electronic products in accordance with legislation that
requires proper treatment, recovery and recycling.

Private household in the 25 member states of the EU, in Switzerland and Norway may return their used
electronic products free of charge to designated collection facilities or to a retailer (if you purchase a similar
new one).

For Countries not mentioned above, please contact your local authorities for a correct method of disposal.

By doing so you will ensure that your disposed product undergoes the necessary treatment, recovery and
recycling and thus prevent potential negative effects on the environment and human health.

Refer all servicing to qualified service personnel. Servicing is
required when the apparatus has been damaged in any way, such
as power-supply cord or plug is damaged, liquid has been spilled
or objects have fallen into the apparatus, the apparatus has been
exposed to rain or moisture, does not operate normally, or has
been dropped.

POWER ON/OFF SWITCH: If the equipment has a Power switch,
the Power switch used in this piece of equipment DOES NOT
break the connection from the mains.

MAINS DISCONNECT: The plug shall remain readily operable.
For rack-mount or installation where plug is not accessible, an
all-pole mains switch with a contact separation of at least 3 mm in
each pole shall be incorporated into the electrical installation of the
rack or building.

FOR UNITS EQUIPPED WITH EXTERNALLY ACCESSIBLE FUSE
RECEPTACLE: Replace fuse with same type and rating only.

MULTIPLE-INPUT VOLTAGE: This equipment may require the use
of a different line cord, attachment plug, or both, depending on the
available power source at installation. Connect this equipment only
to the power source indicated on the equipment rear panel. To
reduce the risk of fire or electric shock, refer servicing to qualified
service personnel or equivalent.

If connected to 240V supply, a suitable CSA/UL certified power
cord shall be used for this supply.

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IMPORTANT SAFETY INFORMATION

eLectroMaGnetIc

coMPatIBILIty

This unit conforms to the Product Specifications noted on the
Declaration of Conformity. Operation is subject to the following two
conditions:

• this device may not cause harmful interference, and

• this device must accept any interference received, including

interference that may cause undesired operation.

Operation of this unit within significant
electromagnetic fields should be avoided.

• use only shielded interconnecting cables.

u.K. MaInS PLuG WarnInG

A molded mains plug that has been cut off from the cord is unsafe.
Discard the mains plug at a suitable disposal facility.

NEVER UNDER ANY CIRCUMSTANCES SHOULD YOU
INSERT A DAMAGED OR CUT MAINS PLUG INTO A 13
AMP POWER SOCKET.

Do not use the mains plug without the fuse cover in place.
Replacement fuse covers can be obtained from your local retailer.
Replacement fuses are 13 amps and MUST be ASTA approved to
BS1362.

DecLaratIon of

conforMIty

Manufacturer’s Name: dbx Professional Products
Manufacturer’s Address: 8760 S. Sandy Parkway
Sandy, Utah 84070, USA

declares that the product:
Product name: dbx 286s

Note: Product name may be suffixed by the EU.
Product option: None
conforms to the following Product Specifications:
Safety: IEC 60065 -01+Amd 1

EMC: EN 55022:2006 (N/A; Analog Product)
IEC61000-4-2
IEC61000-4-3
IEC61000-4-4
IEC61000-4-5
IEC61000-4-6
IEC61000-4-8
IEC61000-4-11
Supplementary Information:

The product herewith complies with the requirements of the:
Low Voltage Directive 2006/95/EC
EMC Directive 2004/108/EC
RoHS Directive 2002/95/EC
WEEE Directive 2002/96/EC

With regard to Directive 2005/32/EC and EC Regulation
1275/2008 of 17 December 2008, this product is designed,
produced, and classified as Professional Audio Equipment and
thus is exempt from this Directive.

Roger Johnsen
Vice-President of Engineering
8760 S. Sandy Parkway
Sandy, Utah 84070, USA
Date: September 10, 2010

European Contact: Your local dbx Sales and Service Office or
Harman Music Group

8760 South Sandy Parkway
Sandy, Utah 84070, USA
Ph: [phone]
Fax: [phone]

Table of Contents

Section 1 - Introduction ........................................1

1.1 Service Contact Info ......................................2

1.2 Warranty ......................................................3

Section 2- Operating Controls ................................4

2.1 Rear Panel ...................................................4

2.2 Front Panel .................................................. 5

Section 3 - Basic Operation ...................................10

3.1 Connecting the 286s to Your System ...............10

3.2 Understanding the 286s Mic Preamp ................10

Section 4 - Problems, Possible Causes, Solutions ......16

Section 5 - Technical Support and Factory Service .....18

Section 6 - Technical Specifications ........................19

Section 7 - Block Diagram .....................................21

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Introduction

Section 1 - Introduction

Congratulations on choosing the dbx 286s Mic Preamp/Processor. The 286s is a powerful,
user-friendly unit, providing concise and intuitive controls for all your mic processing needs,
whether you use a microphone to record vocals and acoustic instruments, sample acoustic
sounds, or for a public address system installation. The 286s is also capable of providing
effective processing for electronic instruments, individual mixer tracks, and other mono sound
sources.

You can think of the 286s as two separate processors, a Mic Preamp Section and a Processing
Section. These two sections can be used together, or the 286s can be used as a dedicated
Mic Preamp by defeating the Processing Section via the front panel BYPASS switch.
Furthermore, the Processing Section provides four specific types of processing: Compression,
De-essing, Enhancement and Expansion/Gating. These four controls can be used in any
combination, as appropriate to your requirements. External audio processors (e.g., equalizer,
delay unit, etc.), can be placed in the signal chain directly between the Mic Preamp Section
and remaining 286s processing via the rear panel INSERT jack. We recommend that you take
a moment and read through the 286s manual to better understand the power of the 286s
processing, and how you can use the 286s to its fullest potential.

Section 1

1

Section 1

286

Introduction

286s

1.1 Service Contact Info

If you require technical support, contact dbx Customer Service. Be prepared to accurately
describe the problem. Know the serial number of your unit - this is printed on a sticker
attached to the bottom panel. If you have not already taken the time to fill out your warranty
registration card and send it in, please do so now.

Before you return a product to the factory for service, we recommend you refer to the manual.
Make sure you have correctly followed installation steps and operation procedures. If you are
still unable to solve a problem, contact our Customer Service Department at [phone]
for consultation. If you need to return a product to the factory for service, you MUST first
contact Customer Service to obtain a Return Authorization Number.

No returned products will be accepted at the factory without a Return Authorization Number.

Please refer to the Warranty information on the following page, which extends to the first
end-user. After expiration of the warranty, a reasonable charge will be made for parts, labor,
and packing if you choose to use the factory service facility. In all cases, you are responsible
for transportation charges to the factory. dbx will pay return shipping if the unit is still under
warranty.

Use the original packing material if it is available. Mark the package with the name of the
shipper and with these words in red: DELICATE INSTRUMENT, FRAGILE! Insure the package
properly. Ship prepaid, not collect. Do not ship parcel post.

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Introduction

1.2 Warranty

This warranty is valid only for the original purchaser and only in the United States.

1. The warranty registration card that accompanies this product must be mailed within 30
days after purchase date to validate this warranty. Proof-of-purchase is considered to be the
burden of the consumer.

2. dbx warrants this product, when bought and used solely within the U.S., to be free from
defects in materials and workmanship under normal use and service.

3. dbx liability under this warranty is limited to repairing or, at our discretion, replacing
defective materials that show evidence of defect, provided the product is returned to dbx
WITH RETURN AUTHORIZATION from the factory, where all parts and labor will be covered up
to a period of two years. A Return Authorization number must first be obtained from dbx by
telephone. The company shall not be liable for any consequential damage as a result of the
product’s use in any circuit or assembly.

4. dbx reserves the right to make changes in design or make additions to or improvements
upon this product without incurring any obligation to install the same additions or
improvements on products previously manufactured.

Section 1

5. The foregoing is in lieu of all other warranties, expressed or implied, and dbx neither
assumes nor authorizes any person to assume on its behalf any obligation or liability in
connection with the sale of this product. In no event shall dbx or its dealers be liable for
special or consequential damages or from any delay in the performance of this warranty due to
causes beyond their control.

3

Section 2

Operating Controls

Section 2 - Operating Controls

2.1 Rear Panel

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286s

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MIC INPUT Jack

The 286s MIC INPUT jack supports professional and home studio microphones by accepting
either balanced or unbalanced signal through an XLR connector. Pins 2 and 3 are
symmetrically balanced and floating; thus, either can be used as “HOT” without difficulty. Pin
2 is in phase with the TIP of all 1/4” connectors. Pin 1 is connected to the 286s chassis
ground.

Note: Use a low impedance mic or a high-to-low impedance matching transformer with a
high impedance mic.

LINE INPUT Jack

Use a 1/4” TRS phone plug to connect line level sources to the 286s (e.g., mixer outputs,
effects loops, electronic keyboards, etc.). The 286s LINE INPUT jack accepts either balanced
or unbalanced signals. Input impedance is 10kΩ unbalanced, 20kΩ balanced.

Note: In general, this jack does not support microphones with 1/4” plugs. Use an
appropriate 1/4”-to-XLR adapter and plug the microphone into the MIC INPUT jack.

s

s

LINE OUTPUT Jack

The 286s LINE OUTPUT jack accepts either balanced or unbalanced 1/4” phone plugs.
Nominal output signal levels is 0dBu into 600Ω, and maximum output signal level is >+21dBu
into 600Ω. Output impedance is 100Ω unbalanced, 200Ω balanced. The output is tip HOT.

INSERT Jack

The 286s INSERT jack allows you to either add an effects loop directly into the 286s circuitry
chain or take a separate mic preamp signal out.

To connect one or more external processors or effects devices (e.g., an equalizer, delay unit,
etc.) between the Mic Preamp Section and the Processing Section, insert a 1/4” TRS plug
carrying the external device’s output signal fully into the 286s INSERT jack; the TIP acts as
a Send, carrying the signal from the Mic Preamp Section at an impedance of 100Ω, while
the RING acts as a Return for external devices to feed the 286s processing circuitry (i.e.,
286s compressor, de-esser, etc.). This operation requires a Y-cable. When using INSERT as a
direct-in to the Processing Section, MIC GAIN control, HIGHPASS button and PHANTOM POWER
will not be active.

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286s

To use the INSERT jack to MULT the preamp out (i.e., to provide an output with a buffered
version of the signal after the Mic Preamp circuitry, but before the Processing Section), insert
a Mono 1/4” plug fully into the INSERT jack, then pull the plug out one click. Plug the other
end of the cable to the appropriate load. This will still allow the original signal path to
continue to the Processing Section without interruption.

Note: If the plug is accidentally pushed fully into the INSERT jack, it will break off the
connection between the Mic Preamp and Processing Sections; in this case, there would be
no signal at the 286s LINE OUTPUT jack.

AC Power

Connect the AC power cord to the AC receptacle on the back of the unit. Route the AC power
cord to a convenient power outlet away from audio lines. The unit may be turned on and off
from a master equipment power switch.

Operating Controls

2.2 Front Panel

Section 2

Note: To reduce the risk of damage to your system, set the MIC GAIN control fully
counterclockwise and lower your playback monitor levels before you connect a microphone,
power on the unit, or press the PHANTOM button. This will eliminate spikes and surges,
acoustical feedback, loud pops, momentary hiss, or other unwanted sounds.

Mic Preamp

MIC GAIN (dB) and LEVEL (dBu) LEDs (including CLIP LED)
Use this control to set the level of gain added to the microphone input signal (or a line-level
input). Note that the 286s processing controls, or an external processor connected to the
286s INSERT, can provide additional gain. Try to set the MIC GAIN control so that you
do no have to reset it repeatedly; allow headroom for the maximum expected levels. For
microphones (connected to the XLR MIC INPUT connector), the 286s can provide +0dB to
+60dB of input gain. For line-level inputs (connected to the LINE INPUT jack), the gain is
from -15dB to +45dB.

Note: To get the lowest noise possible from the 286s, set the input attenuators (if any) on
your recorder or mixer for nominal levels (often about 3/4” of the way up or at the detent
position; refer to the device’s operating manual). Then, set the 286s MIC GAIN so that your
recorder or mixer is at its optimal operating level.

The red CLIP LED (located to the left of the MIC GAIN control) indicates that the combination

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