Russound R275HC User Manual

R-Series

R275HC

2-Channel

Power Amplifier

User’s Manual

2

“WARNING” “ TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK, DO NOT

EXPOSE THIS APPLIANCE TO RAIN OR MOISTURE.”

“CAUTION” “ TO REDUCE THE RISK OF ELECTRIC SHOCK, DO NOT REMOVE
COVER. NO USER - SERVICEABLE PARTS INSIDE. REFER SERVICING TO QUALI­FIED SERVICE PERSONNEL.

The lightning flash with arrowhead symbol, within an equilateral
triangle, is intended to alert the user to the presence of uninsu­lated “dangerous voltage” within the products enclosure that
may be of sufficient magnitude to constitute a risk of electric
shock to persons.

The exclamation point within an equilateral triangle is intended
to alert the user to the presence of important operating and
maintenance (servicing) instructions in the literature accompa­nying the appliance.

SAFETY INSTRUCTIONS

1. Read Instructions - All the safety and operating instructions should be read
before the appliance is operated.

2. Retain Instructions - The safety and operating instructions should be retained
for future reference.

3. Heed Warnings - All warnings on the appliance in the operating instructions
should be adhered to.

4. Follow Instructions - All operating and user instructions should be followed.

5. Water and Moisture - Do not use this appliance near water, for example, near
a bathtub, washbowl, kitchen sink, laundry tub, in a wet basement, or near a
swimming pool. Do not expose the appliance to dripping or splashing, and
do not place on the appliance objects filled with liquids such as vases. Do not
touch the amplifier with wet hands. Do not handle the amplifier or power cord
when your hands are wet or damp. If water or any other liquid enters the
amplifier cabinet, take the amplifier to qualified service personnel for inspec­tion.

6. Cleaning - The appliance should be cleaned only as recommended by the
manufacturer. From time to time you should wipe off the front and side pan­els and the cabinet with a soft cloth. Do not use rough material, thinners,
alcohol or other chemical solvents or cloths since this may damage the finish
or remove the panel lettering.

7. Ventilation - The appliance should be situated so that its location or position
does not interfere with its proper ventilation. For example, the appliance
should not be situated on a bed, sofa, rug, or similar surface that may block
the ventilation openings or, placed in a built - in installation, such as a book­case or cabinet that may impede the flow of air through the ventilation open­ings. Place the unit in a well-ventilated location, leaving at least 2 inches (5
cm) of clearance on all sides, top and rear of unit for air flow. If ventilation is
blocked, the unit may overheat and malfunction.

8. Heat - The appliance should be situated away from heat sources such as radi­ators, heat registers, stoves, or other appliances ( including amplifiers ) that
produce heat.

9. Grounding or Polarization - Precautions should be taken so that the grounding
or polarization means of an appliance is not defeated.

10.Power Cord Protection - Power supply cords should be routed so that they
are not likely to be walked on or pinched by items placed upon or against
them, paying particular attention to cords at plugs, receptacles, and the point
where they exit from the appliance.

11.Power Sources - The appliance should be connected to a power supply only

of the type described in the operating instructions or as marked on the appli­ance.

12.Main Power Disconnect - The power switch is a single-pole switch. When the
switch is in the “Off” position, the appliance is not completely disconnected
from the main power. The main power plug is used as the disconnect device
and shall remain readily operable. When installing the product, ensure that the
plug is easily accessible.

13.Non-use Periods - The power cord of the appliance should be unplugged from
the outlet when left unused for a long period of time.

14.Attachments - Only use attachments/accessories specified by the manufac­turer.

15.Carts and Stands - The appliance should be used only with
a cart or stand that is recommended by the manufacturer.
An appliance and cart combination should be moved with
care. Quick stops, excessive force and uneven surfaces
may cause the appliance and cart combination to overturn.

16.Wall or Ceiling Mounting - The appliance should be mounted to a wall or ceil­ing only as recommended by the manufacturer.

17.Location of the Amplifier - Do not mount this unit under a kitchen cabinet. Do
not expose the amplifier to direct sun light or heating units as the amplifier
internal components’ temperature may rise and shorten the life of the compo­nents. Avoid damp and dusty places.

18.Object and Liquid Entry - Care should be taken so that objects do not fall and
liquids are not spilled into the enclosure through the openings.

19.Servicing - The user should not attempt to service the appliance beyond that
described in the operating instructions. All other servicing should be referred
to qualified service personnel.

20.Damage Requiring Service - The appliance should be serviced by qualified
service personnel when:

A. The power - supply cord or the plug has been damaged; or
B. Objects have fallen, or liquid has been spilled into the appliance; or
C. The appliance has been exposed to rain; or
D. The appliance does not appear to operate normally; or
E. The appliance has been dropped or the enclosure is damaged.

IMPORTANT SAFEGUARDS

3

INTRODUCTION

The Russound R275HC is a 2-channel high-current power
amplifier capable of driving low impedance loads and
incorporates selectable volume control protection circuitry.

This amplifier can be used for power upgrades in specif­ic zones, for large speaker selector or volume control
systems and for long series-parallel speaker runs
(e.g., large outdoor zones).

The R275HC is rated at 75 watts per channel into 8
ohms and 100 watts into 4 ohms. With the
Stereo/Bridge Mono switch in the Bridge Mono position,
both amplifier channels are combined for a higher pow­ered mono output. In Bridge mode the R275HC is rated
at 200 watts of power into a single 8-ohm load. All this
power is backed by a high output toroidal transformer.
Each amplifier output channel incorporates robust pro­tection circuitry for safety and reliability under extreme
circumstances.

FRONT PANEL

RACK MOUNTING

The R275HC amplifier can be rack mounted using the included rack-mount ears and hardware to attach the ears to
the amplifier. The amplifier will take 2 rack spaces with the feet removed.

R275HC AMPLIFIER

Tri-color Indicator LED: The LED will illuminate red when the power is on and the amplifier is in standby,

green when the amplifier is active and orange when in short circuit protection.

1

1

R275HC Side View

Rack Ear
Screw Holes

+

+

Rack Ear
Front View

Rack Ear
Side View

4

1 2 3

4

3

6

58

Power Switch: Turns the amplifier on/off. This

switch does not disconnect the main power feed
from the amplifier; this requires that the power cord
be unplugged from the outlet.

Low Cut (High Pass) Switch: Enables/disables the
filter that reduces very low frequency energy and
protects autoformer-based volume control/speaker
selectors. When “on,” the filter is set to -3dB at 40
Hz. When off, the frequency response is flat from
20Hz to 20kHz.

Gain Controls: Left and Right gain controls inde­pendently adjust the sound level for each channel.
When used in the bridged mode only the Left control
is used.

Loop Output: The loop output is a passive
passthrough of the line input. These jacks can be
used to daisy chain the input signal to another
amplifier in the system.

Speaker A/B Outputs: The A and B speaker out­puts are in parallel to the amplifier output. The mini­mum load in stereo mode is 4 ohms. This can be
used to drive up to 2 pairs of 8-ohm speakers or 1
pair of 4-ohm speakers. The minimum load imped­ance for bridged mode operation is 8 ohms,
Speaker B only.

Stereo/Bridge Mono Switch: Sets the pair of
amplifier channels for stereo or bridge mono opera­tion.

Line Input: The line audio input is a sensing input
that will activate the amplifier when an audio signal
from a source is present. When there is no audio
the zone will go into standby. The Left input is used
for bridged mono operation only.

AC Input: The AC voltage input for the North
American model is 120VAC at 60Hz (for the
European model, 230VAC at 50Hz). This receptacle
accepts a 3-prong IEC 320 type connector. A
detachable 3-terminal power cord is included.

1

2

3

4

5

6

7

5

R275HC AMPLIFIER

7

8

5

R275HC AMPLIFIER

BRIDGED OPERATION

When the amplifier is in Bridged mode operation, both
the left and right channels are combined for a higher
power mono output.

For bridged amplifier operation, turn off the power to the
amplifier and connect an 8-ohm minimum load to the
Speaker B output.

Following the Bridge mode markings in red on the back
of the amplifier: Connect the negative lead (-) of the
speaker cable to the R+ terminal. Connect the positive
lead (+) of the speaker cable to the L+ terminal. Set the
Stereo/Bridge Mono switch to Bridge Mono, connect the
Line In feed from a source to the Left Line In connection
and restore power to the amplifier.

THERMAL PROTECTION

All Russound amplifiers are designed with special circuit­ry to safeguard the amplifier under a thermal overload
condition. Thermal protection mode can only engage
when the unit has been run at high volume for extended
periods of time without adequate ventilation and/or when
speaker impedances are below the minimum levels for
the amplifier. If this fault occurs, turn off the amplifier,
and check that the speaker impedance rating is above
the minimum rating. Also check for adequate ventilation
around the amplifier and make adjustments if necessary.
Once the unit has cooled to safe operating tempera­tures, the amplifier may be powered back on.

PROTECTION CIRCUITRY

All Russound amplifiers are designed with special circuit­ry to safeguard the amplifier under a short-circuit condi­tion. A faulty speaker can also cause a short circuit con­dition.

The front panel LED illuminates orange when the amplifi­er is in short circuit protection. If this fault condition
occurs, turn off the amplifier and check speakers for
short circuit conditions when appropriate.

(+)Positive

(-)Negative

Audio RCA Cable from source

Speaker
cable

8-ohm Speaker

6

POSSIBLE SYSTEM CONFIGURATIONS

The R275HC can be configured for large autoformer­based volume control systems/speaker selectors. When
using the R275HC for this application, set the Low Cut
switch to the “On” position. Turning this filter “on”

enables a filter that reduces the low frequency energy
which protects the volume controls/speaker selectors
and increases the efficiency of the system.

R275HC AMPLIFIER

The R275HC can also be configured as a power upgrade for specific zones, for use with large speaker selectors and
for long series-parallel speaker runs (e.g., outdoor zones).

Line out from Source

IN

Low Cut switch
in “On” position

SPEAKERS SPEAKERS

RUSSOUND

RUSSOUND

SPEAKERS SPEAKERS

INPUT

INPUT

SPEAKERS SPEAKERS

SPEAKERS SPEAKERS

EXPANSIONS

EXPANSIONS

EZB-1SC Modular
Connecting Block

Autoformer-based
volume control

CAM6.6

R275HC Amplifier

RCA Cable

CAM6.6T Controller

8-ohm Speaker

Speaker Cable

Speaker Cable

8-ohm Speaker

8-ohm Speaker

7

SPECIFICATIONS

Stereo Continuous Output Power: 75W per channel at 8 ohms

100W per channel at 4 ohms

Bridged Output Power: 200W at 8 ohms, 2 channels bridged

THD+N: <0.05% from 20Hz to 20kHz

Signal-to-Noise Ratio: >100dB A-weighted

Frequency Response: 20Hz to 20KHz +/- 0.3dB

Input Sensitivity: 70mV for 1W at 8 ohms

610mV for 75W at 8 ohms

Input Impedance: 47kohms Line Input

Voltage Gain: 32dB

Power Requirements:

North American Model:

120VAC 60Hz 2.5A
IEC 320 type connector with 3 terminal detachable power cord.

Power Requirements:

European Model:

230VAC 50Hz 1.2A
IEC 320 type connector with 3 terminal detachable power cord.

Dimensions: 17" W x 14"D x 4.125"H (43 x 35.5 x 10.5 cm)

Weight: 20.3lbs. (9.2kg)

WARRANTY

The Russound R275HC is fully guaranteed for two (2) years from the date of purchase against all defects in materials
and workmanship. During this period Russound will replace any defective parts and correct any defect in workman­ship without charge for either parts or labor. For this warranty to apply, the unit must be installed and used according
to its written instructions. If service is necessary, it must be performed by Russound. The unit must be returned to
Russound at the owners expense and with prior written permission. Accidental damage and shipping damage are not
considered defects under the terms of the warranty. Russound assumes no responsibility for defects resulting from
abuse or servicing performed by an agency or person not specifically authorized in writing by Russound. Damage to
or destruction of components due to improper use voids the warranty. In these cases the repair will be made at the
owners expense. To return for repairs, the unit must be shipped to Russound at the owners expense, along with a
note explaining the nature of the service required. Be sure to pack in a corrugated container with at least 3 inches of
resilient material to protect the unit from damage in transit.

Russound sells products only through authorized Dealers and Distributors to ensure that customers obtain proper
support and service. Any Russound product purchased from an unauthorized dealer or source, including retailers,
mail order sellers and online sellers will not be honored or serviced under existing Russound warranty policy. Any sale
of products by an unauthorized source or other manner not authorized by Russound shall void the warranty on the
applicable product.

R275HC AMPLIFIER

5 Forbes Rd. Newmarket, NH 03857, USA
Tel [phone] • Fax [phone]
e-mail: [e-mail] 28-1167 03/22/05

R-Series

R275HC

2-Channel

Power Amplifier

User’s Manual