875Z
OWNER’S
MANUAL
IMPORTANT SAFETY INSTRUCTIONS
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 product's 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
product.
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Read these instructions.
Keep these instructions.
Heed all warnings.
Follow all instructions.
Do not use this apparatus near water.
Clean only with dry cloth.
Do not block any 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 (includ
ing amplifiers) that produce heat.
Do not defeat the safety purpose of the polarized or grounding-type 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 the third prong are provided for your safety. If the provided plug does not fit into 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.
Only use attachments/accessories specified by the manufacturer.
Use only with the cart, stand, tripod, bracket, or table specified by the manufacturer, or sold
with the apparatus. When a cart is used use caution when moving the cart/apparatus combi
nation to avoid injury from tip-over.
Unplug this apparatus during lightning storms or when unused for long periods of time.
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 oper
ate normally, or has been dropped.
"WARNING: TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK, DO NOT EXPOSE THIS APPARATUS
TO RAIN OR MOISTURE".
"DO NOT EXPOSE THIS EQUIPMENT TO DRIPPING OR SPLASHING AND ENSURE THAT NO OBJECTS
FILLED WITH LIQUIDS, SUCH AS VASES, ARE PLACED ON THE EQUIPMENT".
"TO COMPLETELY DISCONNECT THIS EQUIPMENT FROM THE AC MAINS, DISCONNECT THE POWER
SUPPLY CORD PLUG FROM THE AC RECEPTACLE".
"THE MAINS PLUG OF THE POWER SUPPLY CORD SHALL REMAIN READILY OPERABLE".
875Z - EIGHT CHANNEL POWER AMPLIFIER
Table of Contents
Important Safety Instructions
Inside front cover
General Introduction
Introduction
Description
Shipping Box & Packing Materials
Installation
Wiring the 875Z
Page 1
Front Panel
Power Switch
LED Indicators
Fuses
Page 2
875Z Rear Panel Connectors & Switches
Input Select Switches
Stereo Bus Inputs
Stereo/Series Switch
Channel Direct Input Connectors
Channel Level Control
Speaker Connectors
Mute Options Switch
Page 3
875Z Rear Panel Connectors & Switches contd..
Signal Sense Threshold
External Zone Mute Connector
Power Inlet
Power-Up Connector
Page 4
Typical Hookup of the 875Z
in a 5.1 Home Theatre Installation
Page 5
Block Diagram
Page 6
AC Power Control
External Control Voltage Power Up
AC Power Input
Page 7
Technical Specifications
Page 8
Important Warranty Information
Back Cover
875Z-MANUAL-2004-03-24
875Z - EIGHT CHANNEL POWER AMPLIFIER
INTRODUCTION
Thank you for choosing the 875 Eight Channel Power Amplifier. Bryston welcomes any suggestions you may have, or
comments regarding the operation of your amplifier. We consider you, our customer, to be Bryston’s most important
resource, and your opinion is very much appreciated.
DESCRIPTION
The 875 series is a modular multi-channel audio power amplifier design of 8 x 75 Watts per channel. Currently the 875 is
available in two different versions.
P
875HT:
A Home Theatre version, the “HT” is essentially 4 stereo amplifiers. Each stereo pair selects from bal
anced or single ended inputs. Each stereo pair may be bridged. The gain of the balanced input is 23dB
and the single ended input is 29dB.
P 875Z:
A Home Install version, the “Z” has 4 stereo amplifiers separated into 4 zones that can be independently
muted or respond to program sense circuitry. Each channel can select from a discrete input, or from a
common stereo input when distribution is wanted. The inputs are single ended with a gain of 29dB. Each
stereo pair may be bridged.
The power up sequence of either 875 model may be controlled from a 12v control voltage. The 875 uses ‘soft start’ power
control circuitry to eliminate high inrush currents when A/C power is applied.
WARRANTY (see back page for details )
SHIPPING BOX & PACKING MATERIAL
Please keep the original shipping box and all packing material. This will ensure the amplifier is protected in future transport. In the unlikely event you have a problem and must return it for service you must use the proper packing material.
Ship the amplifier only in the original packing material, as the unit is not insurable by carriers otherwise.
INSTALLATION
The most important installation consideration is ventilation. The 875 series amplifiers are a convection-cooled.
Unrestricted air-flow across its heat sinks is a must. For this reason do not install anything directly above it. Allow 3.5” (2u)
to 5” (3u) inches of space above and to the sides of this amplifier. Do not install directly above other heat generating equipment. Should your installation conditions be constricted, then additional forced air-cooling may be necessary. Any 875
channels thermally shutting down during operation indicates insufficient cooling, and a remedy must be found for cooling
the amplifier. Provide a minimum 6” space to the rear of the 875 for ventilation and dressing cables to and from the amplifier.
Never operate the 875 in a vertical position.
WIRING THE 875Z (also see rear panel description )
Speaker wires should be as short as practical. Use quality wire, and if runs are more than 3 meters use at least 12 gauge
wire. The speaker binding posts will accept wire up to 3 gauge in size. Bryston can custom build cables for your application.
P A/C power:
Before plugging in the power cord be sure your 875 is specified for the correct A/C voltage for your locality. The
voltage is listed by the power input connector. Never lift the safety ground to the amplifier or remove the ground pin
from the plug.
P
Power line conditioners:
The 875’s performance will not improve with the use of power line conditioners. In fact most of the time they restrict
the flow of current in the power line to the amplifier thereby reducing performance at high output levels.
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875Z - EIGHT CHANNEL POWER AMPLIFIER
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FRONT PANEL of 875Z-Blk
FRONT PANEL
POWER switch
The front panel label '875Z POWER’ is a switch used to apply or remove A/C line power to the 875 soft start circuitry.
Push the switch and the 875 will initiate the start up sequence. The switch cap remains indented when circuits are on.
Push the switch again the 875 will initiate the power off sequence.
LED Indicators:
Each 875 channel has a single multi-colour LED indicator to monitor the following conditions:
P
Unlit LED: no power
The 875 channel LED, when unlit, indicates no A/C mains power is present at the channel. If all channel LED indica
tors are unlit the 875 probably needs only to be powered on. A group of 4 LEDs not lighting possibly indicates a
blown group fuse. When checking fuses, unplug the power cord. Use only the specified fuses for your operating volt
age. See FUSES section below.
P
Red LED: muted
Each channel normally mutes momentarily during power up and power down sequences.
P
Green LED: operating normally
P
Flashing Red LED: Clipping
Clipping occurs when the channel output level no longer can follow the level increase at the input (Over driven input
condition). When a 875 channel is driven into clipping the channel led will change from green to red then back to
green when the level is reduced ( Flashing Red ). Momentary clipping can be tolerated, however it indicates that
maximum un-distorted power has been surpassed and potential speaker damage may result if over load conditions
persist. Any amplifier that is constantly operated into clipping indicates a more powerful amplifier is needed for that
application.
P
Orange LED: Thermal Shutdown
The 875 channel has thermal shutdown circuitry to prevent damage due to over heating. Should thermal shutdown
occur, the both stereo channels will mute, and the channel leds will turn orange indicating this condition. When the
channels have cooled to a safe operating condition the channels will return to normal operation. Persistent Thermal
shutdown indicates steps need to be taken to increase airflow across the channels heat sink.
(Also see installation section on ventilation ).
FUSES
There are two fuse holders located at the front edge of the top panel. When checking fuses, power down the unit and disconnect the power cord. Use only the specified fuses as indicated on the label located between the two fuse holders on
the top panel. See photo at top of page.
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875Z - EIGHT CHANNEL POWER AMPLIFIER
875Z REAR PANEL CONNECTORS & SWITCHES
The following is a description of the rear panel switches for the 875 Zone Amplifier and their function. There are 8 x 75
watt amplifiers in the 875B Zone amp. The channels are split into 4 zones each with 2 channels. Each zone will operate
in stereo or the channel outputs may be connected in series to achieve a mono channel of 250 watts. Both channels in
each zone have 4 input options
1) ODD NUMBERED CHANNEL INPUT SELECTORS (Channels 1, 3, 5 or 7):
This four position slide switch selects input signals for this channel and, in SERIES (bridged) mode, it is the sole
input used for the combined channel 1+2, 3+4, 5+6 or 7+8 amplifier channel.
P 1st position (top):
left stereo bus
nd
P 2 position:
right stereo bus
P 3rd position:
sum of left and right stereo bus (mono of stereo bus)
P 4th position (bottom): direct input from RCA jack. (.875 v = 75watts/8ohms)
EVEN NUMBERED CHANNEL INPUT SELECTOR:
Similar to above INPUT SELECTOR SWITCH but only controls the input to channel 2, 4, 6 or 8 when the pair of
adjacent channels is in STEREO mode. In SERIES mode this switch has no effect.
2) STEREO BUS INPUTS:
2 daisy-chained RCA connectors for the left (white) bus input and two daisy-chained RCA connectors for right (red)
bus input. Sensitivity is 875 mV for an ouptput of 75 watts into 8 ohms.
3) STEREO/SERIES SWITCH:
Controls the two channels in this zone.
P STEREO (top position):
individual channels
P SERIES (bottom position):
bridged mode wherein channels 1+2 (using only Ch1 input), or channels 3+4
(using only Ch3 input) or channels 5+6 (using only Ch5 input) or channels 7+8
(using only Ch7 input) are combined into a single, higher power channels.
Sensitivity in SERIES mode = 1.8v input at 250 watts output into 8ohms
4) CHANNEL DIRECT INPUT CONNECTORS:
Sensitivity: 875mV for an output of 75watts into 8ohms
5) CHANNEL LEVEL CONTROL:
Normal or maximum is fully clockwise. Minimum is fully counter clockwise which fully attenuates the input signal.
6) SPEAKER BINDING POST CONNECTORS:
P STEREO mode:
Use the red terminal to feed the + red terminal on the loudspeaker.
Use the black terminal to feed the - black terminal on the loudspeaker
P SERIES mode:
Use the Ch1 red terminal to feed the + red terminal on the loudspeaker and Use the
Ch2 red terminal to feed the - black terminal on the loudspeaker
7) MUTE OPTIONS SWITCH:
P ON (Left position):
P SIG (Centre position):
P EXT (Right position):
Each zone has individual muting options.
Zone will remain on as long as power is on in the amplifier.
Mutes the Zone when the signal is absent for more than 8 minutes.
Zone will mute when 12v is present at the External Zone Mute connector (9).
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875Z - EIGHT CHANNEL POWER AMPLIFIER
8) SIGNAL SENSE THRESHOLD:
When the MUTE OPTIONS SWITCH of any of the four zones is set to the SIG position, that zone is muted unless
the input signal exceeds the threshold level set by the SIGNAL SENSE THRESHOLD control. Only the input levels
of the ODD numbered channels is measured by the sense circuitry (ie ch1 in zone 1, ch3 in zone 2, ch5 in zone 3
and ch7 in zone 4) although both channels in the zone will be muted and un-muted by the SIGNAL SENSE
THRESHOLD mute circuitry. The minimum setting for this threshold is 20mV and is at the fully counter-clockwise
position of the SIGNAL SENSE THRESHOLD control. The maximum threshold is approximately 100mV and is at the
fully clockwise position.
9) EXTERNAL ZONE MUTE CONNECTOR:
When 12 volts is applied between the ‘COM’ pin and a ‘Z’ pin the corresponding Zone will be muted. When the 12
volt control signal is removed, the channel will be un-muted.
10) POWER INLET:
Primary or mains power cord input connector (IEC 320 inlet). Connect the supplied power cord to this connector only
after checking the unit label and verifying that the amplifier is set for your local power requirements for A/C voltage
and line frequency.
11) POWER-UP CONNECTOR:
When an external 12v control signal is applied between the 2 ‘IN’ pins on the connector, the amplifier will power up.
When the 875 has powered up the incoming 12v is handed to the ‘OUT’ terminals to turn on other equipment. This
circuit draws 2 ma to turn the 875 on.
REAR PANEL of 875Z
SPEAKER BINDING POST CONNECTORS
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875Z - EIGHT CHANNEL POWER AMPLIFIER
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875Z - EIGHT CHANNEL POWER AMPLIFIER
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875Z - EIGHT CHANNEL POWER AMPLIFIER
A/C POWER CONTROL
External control voltage power up ( Local / external switch)
To power-up the 875 using an external control voltage, supply a 4v to 12v AC or DC control voltage to the ‘IN’ terminals
of the “Power-Up” connector. The front panel ‘Power’ switch needs to be off for remote operation.
Use paired wire of 22 gauge to 18 gauge between the source device and the 875. The amplifier will now power-up when
the control voltage is present.
Immediately following power up, the control voltage will appear at the ’OUT’ terminals of the “Power-Up” connector for
the control of other equipment.
Removal of the control voltage causes the 875 to turn ‘off’ and the control voltage at the ‘OUT’ terminals is interrupted.
AC power input
This is a high current plug for the power cord receptacle. Check that the voltage rating at the right of the connector conforms with your locality. With the front panel power switch in the off position, insert the power cord into the 875, then plug
the other end to an appropriate A/C power outlet.
Note:
The ‘OUT’ terminals of the “Power-Up” connector are connected to the ‘IN’ terminals once the 875 has powered-up.
The control current across the “OUT” terminals is determined by the source equipment. The carrying current of the
‘OUT’ relay is 2 amps. The 875 itself draws less than 3 mA from the control current when operating.
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875Z - EIGHT CHANNEL POWER AMPLIFIER
Technical Specifications
Power Output
75 watts per channel into 8 ohms
100 watts per channel into 4 ohms
Gain Select and Sensitivity
29dB - .850Vin = 75W @ 8 Ohms - single ended input
23dB - 1.7Vin = 75W @ 8 Ohms - balanced input
Input Impedance
20 Kohms single ended
40 Kohms balanced
Distortion
IMD or THD+noise
< 0.007% 20Hz to 20kHz at 75 watts into 8 ohms,
< 0.010% 20Hz to 20kHz at 100 watts into 4 ohms
Noise
Measured with input shorted - 20Hz to 20kHz.
>105dB below rated output 29dB gain (- 68dBu)
>107dB below rated output 23dB gain (- 70dBu)
Slew Rate
>60 volts per microsecond
Power Bandwidth
<1 Hz to over 100 kHz
Damping Factor
Over 500 at 20 Hz, ref. 8 ohms
Dimensions
W D H: - 19 (or 17) x 19 x 3.5 inches ( 2 rack spaces )
Weight:
approx.. 25kg - 55 lbs.
Power Consumption &Heat Load
max power
typical use
single channel 75W @ 8 ohms 8 channels @ 75W @ 8 ohms Max. Heat Dissipation 8 ohms -
150 Watts
1200 Watts
2400 Btu/Hr.
15 Watts
120 Watts
240 Watts
single channel 100W @ 4 ohms 8 channels @ 100W @ 4 ohms Max. Heat Dissipation 4 ohms At Idle -
210 Watts
1680 Watts
3500 Btu/Hr.
110 Watts
21 Watts
168 Watts
350 Watts
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BRYSTON 20 -YEAR WARRANTY
Bryston products are warranted to be free from
manufacturing defects for a minimum of twenty
years from the original date of manufacture. This
includes parts, labour and return shipping to the
first owner and all subsequent owners. Warranty
coverage is automatic and commences with the
original date of manufacture which is kept on file at
Bryston.
In the event of a defect or malfunction, Bryston will
remedy the problem by repair or replacement, as
we deem necessary, to restore the product to full
performance.
This warranty is considered void if the defect, malfunction or failure of the product or any component
part was caused by damage ( not resulting from a
defect or malfunction ) or abuse while in the possession of the customer. Tampering by persons
other than factory authorized service personnel, or
failure to fully comply with Bryston operating
instructions, voids the warranty.
This warranty gives you specific legal rights and
you may also have other rights which may vary
from province to province and country to country.
BRYSTON SERVICE CANADA:
24 STEINWAY BLVD., UNIT 48
ETOBICOKE, ONTARIO
CANADA M9W 6T8
BRYSTON SERVICE USA:
79 COVENTRY ST., SUITE #5
NEWPORT VERMONT.
U.S.A. 05855-2100
PHONE: 416-675-2585
FAX: 416-675-3103
E-mail: cdnser@gta.igs.net
PHONE: 802- 334-1201
FAX: 802-334-6658
E-mail: usaser@bryston.ca
BRYSTON SERVICE OUTSIDE CANADA & the USA:
CONTACT YOUR LOCAL DISTRIBUTOR
OR
CHECK OUR WEB SITE: www.bryston.ca
E-MAIL BRYSTON DIRECTLY: info@bryston.ca
FAX BRYSTON DIRECTLY:
705-742-0882
PHONE BRYSTON DIRECTLY:
705-743-5325
BRYSTON LTD., 677 NEAL DRIVE, P.O. BOX 2170, PETERBOROUGH, ONTARIO CANADA K9J 7Y4