Knoll Systems GS-8 Owners manual

GS8 and GS12 Eco-Drive™ Amplifier specifications:

Inputs: 8 or 12 gold RCA jacks with adjustable gain
Input impedance: 50k ohms
Outputs: 5 way gold binding posts
Output power: 50 watts RMS per channel (8 ohms)
Peak output power: 100 watts per channel (8 ohms)
Ideal impedance: 4 – 8 ohms
Frequency response: 10 Hz – 40 kHz +/- 1dB (1w)
S/N ratio: Over 105 dB A weighted (50 watts)
THD distortion: Less than 0.1% 20 Hz to 20 kHz
IMD distortion: Less than 0.01% 60 Hz 7 kHz 4:1 (SMPTE)
Dimensions: 17” x 3.5” x 11.5” (432 x 89 x 292 mm)
Fan noise: Quiet 28 dBA
Power: Standby in Eco-Drive™ less than 5 watts

Maximum 750 watts at 117 VAC or 230VAC
Weight: GS8 20 lbs (9 kg); GS12 22 lbs (10 kg)
Construction: Steel chassis, powder coated; glass epoxy
printed circuit boards

Warranty

Knoll Systems warrants its products sold in the USA and Canada by authorized Knoll
dealers to be free of defects in materials and workmanship. This warranty extends for
three full years from the date of purchase by the original consumer. Any products returned
to Knoll Systems and found to be defective by Knoll Systems within the warranty period
will be repaired or replaced at Knoll Systems option, at no charge. Knoll Systems will not
be responsible for the actual cost of installation or removal of the product, nor for any
incidental or consequential damages. Some states do not allow the exclusion or limitation
of incidental or consequential damages, so the above limitation may not apply to you.
This warranty gives you specific legal rights. You may have additional legal rights that
vary from state to state.

Knoll Systems www.knollsystems.com

145 Tyee Drive Point Roberts, WA 98281
11791 Machrina Way, #120 Richmond BC V7A 4V3
tel [phone], fax [phone]

Made in Canada GS18 and GS12, 2005, Knoll Systems All Rights Reserved

GS8 GS12

Eco-Drive Power Amplifiers
Installation Instructions v1.1

Warning: To be installed and/or used in accordance with

appropriate electrical codes and regulations.

Introduction: Thank you for your purchase of a Knoll Eco-Drive
multi-channel power amplifier and congratulations on your
choice. This amplifier is specifically designed to save energy
when idling, which can be most of the time. When compared to
similar power amplifiers the GS8 and GS12 uses less than 5%
of the energy required for normal amps to idle.

FEATURES:

• Eco-Drive™ Circuitry saves energy (and money) and
increases power.

• 12 channels x 50 watts RMS at 8 Ohms (over 100W
peak). GS8 8 channels.

• Individual and automatic channel resetting protection
for low impedance, overheating, overloading,
overvoltage and undervoltage.

• Individual gain controls for all channels.

• Electronic Link feature connects stereo inputs

channel 2 through 6 to channel 1. GS8 connects
stereo inputs channel 2 through 4 to channel 1.

• Side-mounted thermostatically controlled fan for
internal cooling.

• Two rack spaces (3-1/2”) with optional rack mount
version.

The eco-friendly choice

The Knoll GS8 and GS12 are class A/B amplifiers that produce 50
watts per channel at 8 ohms and 70 watts per channel at 4 ohms.
While offering unparalleled reliability, power and sound quality the
GS8 and GS12 offers a Knoll exclusive, the Eco-Drive™ circuit. This
patent pending circuit determines which of the 12 stereo channels (6
pairs) are in use and delivers power only to those channels needing it.
The channels that are “off” are truly off, not in “standby” or “mute”.
With this circuit the active channels share more rail voltage resulting
in more reserve power for the stereo channels in use.

The most important feature of the Eco-Drive™ circuit is the
electrical savings that is delivered to the owner over what a
comparable class A/B amplifier will cost to operate. The typical
homeowner will see a savings of a hundred dollars or more per year in
actual electrical costs and that can be multiplied when taking into
account the increased costs of air conditioning the home to extract
unwanted heat produced by a typical multi-channel amplifier. The GS8
and GS12 also feature a very quiet energy saving thermostatically
controlled fan. A comparable amplifier without the Eco-Drive™
circuit (we should know, we make lots of them) uses about 14 times
(65 watts) as much power while idling in standby. By comparison the
GS12 with Eco-Drive™ uses under 5 watts while idling!

For over 10 years Knoll multi-channel amplifiers have sold around the
world because of their legendary reliability and unparalleled sound
quality. The GS8 and GS12 take the next logical step by being eco­friendly. Please consider the environment when choosing your next
system.

Sound cuts out 1. Verify speaker impedance is 4-16 ohms.
Changing speakers may be required.

2. Check if the amp feels hot. If it's
hot, increase cooling - see Installation.

Sound is distorted 1. Turn the volume down.

2. Check speakers for damage.

3. Check inputs for proper levels.
GS8 or GS12 gain and source output level
may have to be adjusted.

4. Speakers may be less than 4 ohms.

GS8 or GS12 does not 1. Turn GS8 or GS12 power switch off (out).
turn off 2. With the power switch on, and all input
channels music source turned on, very slowly
adjust “SENS” on rear of amplifier in a
clockwise direction until amp turns off.

Speaker pops when 1. Speaker may need resistor placed
amp turned on or off across terminal. Suggest 2k0 1/4 w.
This discharges the speaker internal cap.

8. Make sure the speakers in each room are connected in phase with
the amplifier + going to the speaker +. Out of phase speakers give
unstable imaging and poor bass response.

9. Connect the AC power into an outlet than can supply at least six
amps (750 watts) dedicated to each GS8 or GS12.

10. After the amp has been turned on adjust the “SENS” pot on the
rear of the amplifier if necessary. The “SENS” adjustment can be
adjusted up (clockwise) to make the amp less susceptible to be turned
on due to nuisance noise and hum. If it is adjusted too high, the amp
may delay turn on or turn off during a quiet music or speech passage.

Caution: Never listen to sound that is distorted. If distorted sound is
heard, turn the volume down immediately or speaker and/or amplifier
damage could occur that is not covered by the warranty. If this
problem persists, contact your dealer.

User Adjustments and Service: There are no user adjustments
inside the GS8 or GS12. Your installer may make certain gain and
sensitivity level adjustments on the rear panel.

Caution: The GS8 or GS12 contains no user serviceable parts, so do
not attempt to open or repair the GS8 or GS12.
Refer servicing to a qualified technician only or contact the factory
for information.

Troubleshooting

If a problem is encountered with the GS8 or GS12 amplifier, the
most expedient procedure is to locate the problem and if possible
repair it before requesting service. Be sure to carefully check other
system components such as controllers, CD players, volume controls,
wiring, speakers, etc. that may be at fault.
Problem Action
Power led does 1. Check that the GS8 or GS12 is plugged in.
not light - no sound 2. Test the AC outlet with a lamp.

3. Check GS8 or GS12 power button on (in).

4. Slowly turn down the “SENS” adjustment
(counterclockwise) on the amplifier rear,
until the amplifier just turns on.

Installation

Installing the amplifier should be relatively easy. With a bit of
planning, this amplifier will give trouble free service for years.

1. The most important consideration when installing the GS8
and/or GS12 is cooling. This amplifier has a lot of power packed into

a small chassis size. When installing it in an equipment stack, it should
be the top component. It needs at least 3"-5" of space above the
amplifier to allow for adequate convection cooling.

2. When installing the GS8 and/or GS12 in a rack we suggest adding
a 3-1/2" blank above and below the amplifier. In multiple GS8 and
GS12 installations, plan for a 3-1/2" blank (double) between each
amplifier and a 3-1/2" blank on the top and bottom. Amplifiers should
always be the top components in a rack system.

3. The GS8 and GS12 are available as an optional 19" EIA rack mount
style.

4. Never operate a GS8 or GS12 on its side, as the cooling potential
drops significantly when operated on the side.

5. Connect the GS8 or GS12 RCA inputs to the source component
outputs with good quality, short as possible RCA jack cables. Connect
each channel individually.

6. Connect the GS8 or GS12 speaker outputs to speakers using good
quality speaker wire. Minimum 16 gauge copper wire is recommended
with 14 gauge minimum for runs over 30' (10m). Fire-rated wire may
be required if installing wires inside walls, ceilings or floors.

Note: Ideally the GS8 and GS12 amplifiers like 6-8 ohm loads.
Connecting to 4-ohm loads won't hurt the amplifier, but the channels
connected to 4-ohm loads may occasionally shutdown due to
overloading. Never connect any GS8 or GS12 amplifier to less than 4
ohms.

7. Individually adjust the channel gains as required. Ideally, all gains
are fully on (fully clockwise).

GS12 Rear Panel

The Link button is normally set to the in position to give all six
stereo inputs individual sources. When a channel Link button is
set to the out position, that channel is (Left/Right) linked or
cascaded to input #1 (without the use of Y cords). Any or all
combinations of linked inputs 2 to inputs 6 are possible. When
all inputs are linked to input one, the input impedance is about
8500 ohms.

Note: When linked unused RCA inputs can be used as outputs to
other amplifiers.

Note 1: Ideal speaker impedance is 6-8 ohms.

Caution: NEVER connect the GS8 or GS12 to impedances less
than 4 ohms or amplifier damage not covered by the warranty
may occur.

The “SENS” pot controls the level threshold setting of the
automatic power on and off to all channels. Each channel turns
on and off individually.

Power On

Initially adjust the “SENS” on to about 1/3 level. Turn on a
source to one or more channels and see if the channel turns on
(observe the front panel led). With soft music on, the channel
should sense the music and turn on. If it does not turn on, try
turning the “SENS” adjustment counter clockwise slowly until
the channel turns on.

Power Off

If the channel does not turn off about 3-30 seconds after a
source has been muted or shut off, adjust the “SENS” slowly
clockwise and wait 30 seconds. If it still does not turn off,
turn it a bit more clockwise and wait another 30 seconds. Keep
doing this until the channel turns off in 3-30 seconds.