Knoll 4K, 6K User Manual

Warranty

Knoll Systems warrants MA1250 amplifiers 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 decision, 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.

Specifications: 4K (eight channel)/6K (twelve channel)

Inputs 8/12 Gold RCA jacks with adjustable gain

Input impedance 50k ohms

Outputs Gold 5 way 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)

Trigger control 12 VDC 35mA on 3.5mm mono jack

Dimensions 17" x 3.5" x 11.5" (432 x 89 x 292mm)

Fan Noise quiet 26 dBA

Power 550/750 watts at 117 VAC or 230 VAC

Weight 21 lbs (9.5 kg)

Note: Specifications subject to change without notice.

Knoll Systems

145 Tyee Drive Point Roberts, WA 98281
12140 Horseshoe Way, Richmond, BC V7A 4V5
Tel: [phone], fax [phone]

Made in Canada

4K and 6K Amplifier

8 and 12 Channel Amplifier Installation Instructions v1.3

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

electrical codes and regulations.

Description: The 4K and 6K are members of the long line of Knoll
multi-channel amplifiers. Designed primarily for the custom install
industry, they are used to power speakers with different or similar
sources in multiple rooms. With 8 or 12 channels rated at 50 watts per
channels at 8 ohms, these amplifiers pack some serious punch. Each
channel has a gain control. The amplifier can be turned on and off via
the front panel power switch or via the 12 VDC trigger. 4K channels 3-8
can be linked to channel 1-2 individually using the link switches. 6K
channels 3-12 can be linked to channel 1-2 individually using the link
switches. 4K and 6K amplifiers designed to meet the amplifier needs of
custom installed systems where high-quality sound is a specific
requirement.

Key Features:

1. Size efficiency. The 4K has eight power amplifiers and the

6K has twelve power amplifiers each in one 3-1/2” high
enclosure. Each power amplifier channel can deliver 50 watts
RMS into an 8-ohm load.

2. Automatic protection circuitry. Each amplifier channel is
individually and fully protected against low impedance,
overheating, overloading, overvoltage and undervoltage. The
protection circuitry automatically restores the amplifier channel
as soon as its parameter returns to the safe operating area.

3. Individual input gain adjustment. Each channel features
an rear chassis input gain adjustment pot to adjust each channel
for gain and speaker sensitivity variations.

4. External power on/off. The 4K and 6K can be turned off
and on by external controllers using the 12 VDC trigger jack.

5. Stackable 17" chassis with 19” EIA rack version option.

6. Link Feature. Certain installations require that some or all of

the stereo channels play the same content. Instead of using Y
cords, "link" cascades any or all of channels 2-6 to channel 1
(l/r) on model 6K. With 4K link channels 2-4 to channel 1 (l/r).

Important Safety Instructions: Hum and noise

1) Read these instructions.

2) Keep these instructions.

3) Read all warnings.

4) Follow all instructions.

5) Do not use this apparatus near water.

6) Clean only with dry cloth.

7) Do not block any ventilation openings. Install in accordance with the manufacturer’s
instructions.

8) Do not install near any heat sources such as radiators, heat registers, stoves, or
other apparatus (including amplifiers) that produce heat.

9) 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 prongs are
provided for your safety. If the provided plug does not fit into your outlet, consult an
electrician for replacement of the obsolete outlet.

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

11) Only use attachments/accessories specified by the manufacturer.

12) 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 combination to avoid injury from tip-over.

13) Unplug this apparatus during lightning storms or when unused for long periods of
time.

14) 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.

15).Under no circumstances should the output terminals of the amplifier be short­circuited.

16).Be sure that the loudspeakers connected can handle the output power of the
amplifier at the loudspeakers rated impedance. The warranty on the amplifier does not
cover damage to loudspeakers that have inadequate power handling capabilities.

17) Where an all-pole MAINS SWITCH is used as the disconnect device, the location
on the apparatus and the function of the switch shall be described, and the switch shall
remain readily operable;

18) A push button is used to turn the power off and on.

19) A LED is used to show when the apparatus is powered on.

CAUTION: These servicing instructions are for use by qualified service personnel only.
To reduce the risk of electric shock do not perform any servicing other than that
contained in the operating instructions unless you are qualified to do so.

WARNING: This product contains chemicals, including lead, known to the
State of California to cause birth defects or other reproductive harm.

Wash hands after handling.

In most cases, one of the following suggestions should help you
solve a hum noise in your system. Please try these steps in the
order shown, proceeding from one step to the next if the prior
suggestion does not eliminate the problem.

Suggestion #1

To determine if a cable TV connection is responsible for the hum, first
turn off all the components. Disconnect the cable TV feed to your
system at the first place where it connects to your components.
Alternatively, disconnect the cable TV wire where it is connected at the
wall outlet. Turn your system back on, and listen if the hum has
disappeared. If removing the cable TV feed has eliminated the hum,
you will need to insert a Ground Loop Isolator (Knoll model GB634)
before reconnecting the cable TV feed, or contact your cable TV
operator to see if they can better isolate your cable feed.

Suggestion #2
Turn off all components in your system and then disconnect the input
cables at the amplifier. Turn the amplifier back on to see if the hum is
still present. If the hum disappears, the fault may be in the input cables
used. Try replacing them with cables that have better shielding, and
make certain that the input cables are not running on top of any AC
power cords. Change the cables one at a time to determine if one or all
cables are responsive. If the hum disappears when the input cables are
disconnected but returns after the cables are changed and the system
reconnected, your source device may be causing the problem.

Suggestion #3

Poor grounding of the electrical system in your home may also cause
ground loop problems, particularly when there are multiple components
with three prong, grounded, power cords. Unplug these components
one at a time, and see if one or all of them is causing the problem. The
ultimate solution to this type of problem is to rewire your house with an
isolated, star type-grounding configuration. Knoll understands that this
may be impractical and expensive. In some instances, the use of an
approved AC Power Isolation Transformer (Knoll model PLB200) of
sufficient capacity may solve this problem.

Warning: If you suspect that the grounding system in your
home’s electrical wiring is causing the hum problem, it is
important that you do not make any changes to the wiring. Only
a licensed electrician should make any changes to household
wiring and they must be made in full compliance with all local
building, safety and electrical codes.