GRS44
8 Channel Eco-System™
Controller-Amplifier
Installation Instructions v1.1
3
FCC Warning
Note: This equipment has been tested and found to comply with the limits for a Class B digital device,
pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against
harmful interference in a residential installation. This equipment generates, uses and can radiate radio
frequency energy and, if not installed and used in accordance with the instructions, may cause harmful
interference to radio communications. However, there is no guarantee that interference will not occur in a
particular installation. If this equipment does cause harmful interference to radio or television reception,
which can be determined by turning the equipment off and on, the user is encouraged to try to correct the
interference by one or more of the following measures:
Reorient or relocate the receiving antenna.
Increase the separation between the equipment and receiver.
Connect the equipment into an outlet on a circuit different from that to which the receiver is
connected.
Consult the dealer or an experienced radio/TV technician for help.
Canada
This Class B digital apparatus complies with Canadian ICES-003.
Cet appareil numérique de la classe B est conforme à la norme NMB-003 du Canada.
Caution: To reduce the risk of electrical shock, do not remove the cover (or back).
No user serviceable parts inside. Refer to qualified service personnel.
Warning: To reduce the risk of fire or electric shock, do not expose this appliance to
rain or moisture.
The lightning flash with arrowhead, within an equilateral triangle, is
intended to alert the user to the presence of uninsulated “dangerous
voltage” within the products that may be of sufficient magnitude to
constitute a risk of electrical shock to persons.
The exclamation point within an equilateral triangle is intended to alert
the user to the presence of important operation maintenance (servicing)
instructions in the literature accompanying the appliance.
4
Introduction: Thank you for your purchase of a Knoll GRS44 8 channel
controller amplifier and congratulations on your choice. The GRS44 features
four deluxe digital volume controlled stereo amplifiers with individual four
source selection. This is Knoll's fourth generation of multi-channel, high-
quality power amplifiers. The GRS44 is designed to meet the amplifier needs
of custom installed multi-zone systems where high quality sound is a specific
requirement.
Each of the four zones or rooms can select any of the four inputs, with
individual volume control, bass and treble. Only the power button is located
on the front panel.
The GRS44 is controlled by RS232 commands.
Four input source selection. Each of the four stereo amplifiers is provided
with four input source selection. Selection, volume level, bass and treble is
made using RS232 commands. Rooms can have different source selections,
volumes, etc.
Four internal 80 position stereo volume controls.
GRS44 consists of a total of 8 power
amplifiers in one 3-1/2" high enclosure (two rack spaces). Each power
amplifier channel can deliver 30 watts RMS with peaks of 60 watts. Because
of its unique design the GRS44 delivers exceptional value.
GRS44 amplifier channel is
individually and fully protected against low impedance, overheating,
overloading, over voltage and under voltage. The protection circuitry
automatically restores the amplifier channel as soon as its parameter returns
to the safe operating area.
and treble adjustment. Each channel features adjustments
so installers can preset the room for speaker differences and listener
preferences.
1 has line level outputs so more powerful power amplifiers can be
connected to this output. The line level output is controlled as to volume,
bass, treble and source selection.
5
Unpacking: The carton and packing materials used in shipping your new amplifier
were specially designed to protect it from the shock and vibration of shipping. We
suggest that you save the carton and packing materials to use if you move, or if the
unit ever needs to be shipped back to us for any reason. Should you discover that
your amplifier has been damaged during shipping, please contact your dealer or
Knoll immediately and request the name of the carrier so a written claim can be
made.
The right to a claim against a public carrier can be forfeited if the
carrier is not notified immediately in writing and if the shipping
carton and packing materials are not available for inspection by the
carrier. Save all packing materials until the claim is settled.
GRS44 placement
During normal home operation the amplifier will become warm. However, there are
instances during high-level playback into low impedance speakers when the amplifier
will become much warmer than normal. To ensure the amplifier’s trouble-free
operation, it is necessary to provide adequate ventilation. Your amplifier should be
kept away from external sources of heat such as radiators and hot-air ducts. The
amplifier should never be placed with other heat-producing components in a cabinet
or enclosure lacking free airflow. Do not stack other components on top of your
amplifier.
Connecting your amplifier
When making connections between any source components and the amplifier, or
when making connections to any speaker, be certain that both the input devices and
the amplifier are turned off. Unplug all equipment before making any connections so
that there will be no unwanted signal transients that can damage equipment or
speakers.
Input connections
Connecting the GRS44 to your source equipment is straightforward. Using the high-
quality RCA audio interconnect cables, match the output channel designations on the
rear of your source equipment to the input jacks on the rear panel of your amplifier
that have the same channel name.
When making connections with RCA type plugs on interconnect cables, make certain
to gently, but firmly, insert the plug into the jack. Loose connections can cause
intermittent sound and may damage your speakers. Some quality RCA plugs may be
very tight, and it is important to secure a proper connection between the
interconnection cable and the input jack.
We suggest starting with the input gains on the rear of the GRS44 set to mid
position. After it is installed and being tested these gains are use to set the different
source input levels so they are roughly the same. Some sources such as DVD players
have a very high output and may cause the GRS44 to send clipped signals to the
speakers even at low volume levels, so we suggest lowering the input gains of that
input in this case to stop the clipping
6
Speaker connections
The GRS44 has four stereo 30 watts per channel amplified outputs. Channel 1 also
has line level outputs to connect to larger powered amplifiers.
To ensure that the high quality signals produced by your amplifier are carried to your
speakers without loss of clarity or resolution, Knoll advises that you use high-quality
speaker wire. Many brands of wire are available — the choice may be influenced by
the distance between your speakers and the amplifier, the type of speakers you use,
personal preferences, along with other factors.
Regardless of the brand or type of speaker wire chosen, we suggest that you use a
wire constructed of fine, multi-strand copper with a gauge of 16 or less (the lower
the number, the thicker the cable). Wire with a gauge of 16 may be used for short
runs of less than 12 feet. We do not recommend that you use any wires with an AWG
equivalent of 18 or higher due to the power loss and degradation in performance.
To connect the amplifiers to your speakers, a removable plug with screws is provided
for each stereo channel output. Strip approximately 1/4 inch of insulation from the
end of each wire and carefully twist the strands of each conductor together. Be sure
not to cut the individual strands or twist them off. All strands must be used for
optimal performance. Insert the wire into the plug and screw the screws very tight.
Inspect that no wire “hairs” that can short circuit are not in the plug.
Correct polarity connections are important to maintain proper speaker phasing.
When speaker phasing is correct, all speakers move in and out at the same time
preserving the imaging of the program material. Out-of-phase connections mean
that some turn off, check your speakers to verify that they are operating properly. If
all other potential sources of trouble check out properly, contact Knoll for further
assistance.
Run the cables to speaker locations. Do not coil any excess cable, as this may
become an inductor that creates frequency response variations in your system.
Lastly, connect the wires to the speakers, again being aware of proper polarity.
Remember to connect the negative, or black wire, to the matching terminal on the
speaker. The positive, or red wire should be connected to the matching terminal on
the speaker.
Note: While most speaker manufacturers follow industry convention of using red
terminals for positive connections and black terminals for negative, some
manufacturers may vary from this configuration. To ensure proper phase
connections, and optimal performance, consult the identification plate on our speaker
terminals, or the speaker’s manual to verify polarity. Contact the speaker’s
manufacturer if you do not know the polarity of your speakers.
7
RS232 Connection
The RS232 connection is used to control the GRS44 by an external controller or
computer and can work with our without keypads. The GRS44 connects to the RS232
controller with a 9-pin db9 connector. The programming reference follows.
1.0 Terminal Settings
To control the GRS44 amplifier via other control systems, connect a RS-232 cable to the serial
control connector on the rear of the GRS44 and set your computer’s or control unit port settings
to match the following configuration:
SETTING
VALUE
Bits per second
Data bits
19,200
8
Parity
Stop bits
None
1
Flow control
Emulation
None
Auto detect
1.1 Command Summary
All commands are enclosed in parentheses. The request can be in some cases a read request
(followed by a “?”), or a write request (followed by 0-2 ASCII digits). A read command will return
the current setting, and write command will change the setting.
Read request format: (nAA?) where:
(
starts the command
n
AA
?
denotes amplifier channel (if required)
denotes the command (may be 1 or 2 letters)
denotes the read request
)
ends the command
Read Request Example 1.1:
Function
Command
Response
Volume
(1vl?)
returns the volume on channel 1 (0-87)
Write request format (nAA$$) where:
(
starts the command
n
denotes the amplifier channel (if required)
AA
$$
)
denotes the command (may be 1, 2 or 3 letters !!)
denotes the value to be written if required (leading zero’s ARE necessary)
ends the command
Write Request Examples 1.2:
Function
Command
Response
Turn Channel On
Select Input
Set Volume
(1on)
(1sl4)
(1vl50)
turns on amplifier channel 1 on
turn amplifier channel 1 to input 4
turn amplifier channel 1 to volume 50
(of 87)
8
Supported Commands
Command Summary
# = numerical zone or amplifier channel value
$$ = second numerical value (may be one or two digits)
Function
Command
Range
Read/Write
Remarks
Version
Reset
Channel On
Channel Off
Mute
Un-mute
Mute All
Un-mute All
Volume Request
Volume Set
Volume All
Input Request
Input Set
Input Select All
All Channels On
All Channels Off
All Channels Vol up
All Channels Vol dn
Channel Vol up
Channel Vol down
Bass adjustment
Treble adjustment
Display treble
Display bass
(vr?)
(rx)
(#on)
(#of)
none
none
1-4
1-4
1-4
read only
write only
write only
write only
write only
write only
write only
write only
read only
write only
write only
read only
write only
write only
write only
write only
write only
write only
write only
write only
write only
write only
read only
read only
1 second
(#mu)
(#um)
(amu)
(aum)
(#vl?)
(#vl$$)
(avl$$)
(#sl?)
(#sl$)
(asl$)
(aon)
(aof)
(avlu)
(avld)
(#vlu)
(#vld)
(#b$)
(#t$)
1-4
Note 3
Note 3
none
none
1-4
1-4 / 0-87
0-87
1-4
1-4 / 1-4
1-4
none
none
none
none
1-4
Note 3
Note 1
Note 1
Note 1
Note 1
Note 2
Note 2
1-4
1-4 / 0-F
1-4 / 0-F
1-4
(#b?)
(#t?)
1-4
Note1: Volume up or down requests increase or decrease volume level by 5
Note 2: Treble and bass commands use hexadecimal values 0-F, default (flat) is 8.
Note3: After “ALL Channels Off” command an “Un-mute” must be sent to each channel to
restore a channel volume.
Also, it is best to leave about a ½ second between commands, as some integrators may miss
commands if they are entered too quickly.
All commands also send a message back to the terminal after they have been completed, so that
it is easy to keep track of the previous commands that were sent.
Note: Some commands are read or write only and some are both – for example:
Mute All is a write only command and Version is a read only command.
Supported Command Messages
Function
Command
Message
Version
Reset
(vr?)
(rx)
Version Number
“Resetting...”
Channel On
Channel Off
Mute
Un-mute
Mute All
(#on)
(#of)
(#mu)
(#um)
(amu)
“Zone # on”
“Zone # off“
“Zone # muted”
“Zone # unmuted”
"All channels muted"
9
Un-mute All
Volume Request
Volume Set
Volume All
Input Set
Input Request
Input Select All
All Channels Off
All Channels On
All Channels Vol up
All Channels Vol dn
Channel Vol up
Channel Vol down
Bass adjustment
Treble adjustment
(aum)
(#vl?)
(#vl$$)
(avl$$)
(#sl$)
(#sl?)
(asl$)
(aof)
(aon)
(avlu)
(avld)
(#vlu)
(#vld)
(#b$)
(#t$)
"All channels un-muted"
"Zone # volume level = $$"
"Zone # volume level set"
"All volume levels successfully changed"
"Zone # input set"
"Zone # is currently using input channel $”
"All zones set to source $"
"All zones turned off"
“All zones turned on”
“All zones volume levels increased”
“All zones volume levels decreased”
“Zone # volume increased”
“Zone # volume decreased”
“Bass successfully set to $”
“Treble successfully set to $”
Example 1.3: We will use the example commands from before, and show you an example of
what the responses may look like
Function
Command
Response Window
On/Off
(1on)
(1sl3)
(1vl50)
(1baf)
(2ta)
Zone 1 on
Zone 1 input 3 set
Zone 1 volume level = 50
Zone 1 Bass successfully set to 15
Zone 2 Treble successfully set to 10
Zone 2 volume increased
Select Input
Set Volume
Set Bass
Set Treble
Increase Volume
(2vlu)
Knoll Systems service information
The GRS44 amplifier does not contain any user serviceable parts inside. If you suspect a
phone at 800 566-5579. It is extremely important that only an authorized service dealer make
any repairs. This will ensure proper service and preserve the protection of your warranty.
Keep your receipt in a safe place so that it will be available to verify the purchase date, should
you experience a problem covered by Knoll System’s warranty.
10
Troubleshooting
Your Knoll amplifier is designed from trouble-free operation. If you follow the
instructions in this manual, you should enjoy many years of high-quality listening
enjoyment. However, as with any sophisticated device, there may be occasional
problems upon initial installation, or during the life of the amp. The items on the list
below are a brief guide to the minor problems that you may be able to correct
yourself. If these solutions do not help, or if the problem persists, contact us for
assistance at 1800 566 5579 in Canada or the USA or 604 940 1689. We are in the
Pacific time zone.
Problem
Solutions
Amplifier won’t turn on
Master power switch turned off (No power light LED).
Turn on Master Power Switch.
Amplifier turns on, but no audio
from one or more channels
Input plugs not connected to proper jack or are loose.
Check input connections.
No audio from one or more
Channels
Speakers are not connected properly. Check speaker
connections at amp and speaker.
Audio levels differ from sources
Improper settings or output levels from source device.
Check the settings on your preamp, processor or
controller. Also verify gain settings on the source
inputs on the GRS44 rear panel.
Audio plays and then cuts off
Amplifier may be shorted. Check speaker connections
for short-circuit at amp and speaker.
Care, maintenance, and cleaning
When the GRS44 amp becomes dirty, wipe it with a clean, dry, soft cloth. If necessary, first
wipe the surface with a slightly dampened soft cloth with mild soapy water, then with a fresh
cloth dampened with clean water. Wipe dry immediately with a dry cloth. NEVER use benzene,
thinner, alcohol, or any other volatile cleaning agent. Do not use abrasive cleaners, as they
will damage the finish of the metal parts. Avoid spraying insecticide, waxes, polishing agents,
or any aerosol product near the GRS44.
11
Limited Warranty Knoll Systems, Inc. (“Knoll”) warrants that each GRS44 (“the Product”)
sold hereunder will conform to and function in accordance with the written specifications of
Knoll. Said limited warranty shall apply only to the first person or entity that purchases the
Product for personal or business use and not for the purpose of distribution or resale. Said
warranty shall continue for a period of three years from the date of such purchase. Knoll does
not warrant that the Product will meet the specific requirements of the first person or entity
that purchases the Product for personal or business use. Knoll’s liability for the breach of the
foregoing limited warranty is limited to the repair or replacement of the Product or refund of
the purchase price of the Product, at Knoll’s sole option. Replacement Product may be re-
furbished in “like-new” condition, at Knoll’s sole discretion. To exercise the Purchaser’s rights
under the foregoing warranty, the Product must be returned at the Purchaser’s sole cost and
expense, to Knoll or to any authorized Knoll service center provided, and the Product must be
accompanied by a written letter explaining the problem and which includes (i) proof of date of
purchase; (ii) the dealer’s name; and (iii) the model and serial number of the Product. When
sending your unit in for repair, please ship your unit in its original packing material or a Knoll
approved ATA Shipping Case, or have a professional packaging company pack the unit. Please
insure your shipment for its full value. A return authorization number, issued by the Knoll
customer service department, must also be clearly displayed on the outside of the shipping
carton containing the Product.
Note: Remanufactured Products are exempt from the foregoing Limited Warranty. Please refer
to the Remanufactured Product Warranty for applicable warranty information.
WARRANTY LIMITATION AND EXCLUSION Knoll shall have no further obligation under the
foregoing limited warranty if the Product has been damaged due to abuse, misuse, neglect,
accident, unusual physical or electrical stress, unauthorized modifications, tampering,
alterations, or service other than by Knoll or its authorized agents, causes other than from
ordinary use or failure to properly use the Product in the application for which said Product is
intended.
DISCLAIMER OF UNSTATED WARRANTIES THE WARRANTY PRINTED ABOVE IS THE ONLY
WARRANTY APPLICABLE TO THIS PURCHASE. ALL OTHER WARRANTIES, EXPRESS OR
IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. THERE ARE NO
WARRANTIES THAT EXTEND BEYOND THE FACE HEREOF AND THE FOREGOING WARRANTY
SHALL NOT BE EXTENDED, ALTERED OR VARIED EXCEPT BY WRITTEN INSTRUMENT SIGNED
BY KNOLL. SOME STATES DO NOT ALLOW LIMITATIONS ON HOW LONG AN IMPLIED
WARRANTY MAY LAST, SO SUCH LIMITATIONS MAY NOT APPLY TO YOU.
LIMITATION OF LIABILITY IT IS UNDERSTOOD AND AGREED THAT KNOLL’S LIABILITY
WHETHER IN CONTRACT, IN TORT, UNDER ANY WARRANTY, IN NEGLIGENCE OR OTHERWISE
SHALL NOT EXCEED THE RETURN OF THE AMOUNT OF THE PURCHASE PRICE PAID BY
PURCHASER AND UNDER NO CIRCUMSTANCES SHALL KNOLL BE LIABLE FOR SPECIAL, INDI-
RECT, INCIDENTAL OR CONSEQUENTIAL DAMAGES OR LOST PROFITS, LOST REVENUES OR
LOST SAVINGS. THE PRICE STATED FOR THE PRODUCT IS A CONSIDERATION IN LIMITING
KNOLL’S LIABILITY. NO ACTION, REGARDLESS OF FORM, ARISING OUT OF THE AGREEMENT
TO PURCHASE THE PRODUCT MAY BE BROUGHT BY PURCHASER MORE THAN ONE YEAR
AFTER THE CAUSE OF ACTION HAS ACCRUED. SOME STATES DO NOT ALLOW THE EXCLUSION
OR LIMITATION OF INCIDENTAL OR CONSEQUENTIAL DAMAGES SO THE ABOVE LIMITATION
OR EXCLUSION MAY NOT APPLY TO YOU. THIS LIMITED WARRANTY GIVES YOU SPECIFIC
LEGAL RIGHTS, AND YOU MAY ALSO HAVE OTHER RIGHT WHICH VARIES FROM STATE-TO-
STATE.
Copyright 2013 Knoll Systems. All Rights Reserved.
Knoll Systems
14-7163 Vantage Way, Delta BC V4G 1N1 Canada
145 Tyee Drive, Point Roberts, WA 98281 USA
Made in Canada
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