Knoll Systems service information

The MX855 amplifier does not contain any user serviceable parts inside. If you suspect a problem that may require servicing, contact us at www.knollsystems.com/contact.html, or by phone at 800 566-5579.

Troubleshooting

If a problem is encountered with the MX855, 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 MX855 is plugged in.

not light - no sound

2.

Test the AC outlet with a lamp.

 

3.

If remote on/off is used, check that

 

 

the trigger voltage is at 12 VDC.

 

4.

Check MX855 power button on (in).

Sound cuts out

1.

Verify speaker impedance is 4-16 Ω.

 

 

Changing speakers may be required.

 

2.

Check if the MX855 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.

 

 

MX855 gain and source output level

 

 

may, have to be adjusted.

 

4.

Speakers may be less than 4 Ω.

MX855 does

1.

Push MX855 power switch off (out).

not turn off

2.

If trigger is being used, power switch

 

 

needs to be set to off (out) position

 

 

or amp is on all the time.

 

3.

Try disconnecting trigger jack.

Trigger does not

1.

Measure the trigger voltage with a volt

work

 

meter. It needs to be 11-15 volts DC

 

 

to work (current is about 35mA total

 

 

per amp). See page 5 for details.

Speaker pops when

1.

Speaker may need resistor placed

amp turned on or off

 

across terminal. Suggest 2k0 1/4 w.

 

 

Discharges speaker internal capacitor.

Installation

Installing the MX855 should be relatively easy. With a bit of planning, it will give trouble free service for years.

1.The most important consideration when installing the MX855 is cooling. The MX855 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.Amplifiers should always be the top components in the system.

3.If MX855 channels frequently shutdown due to overheating, install a fan directed up from the MX855 bottom center.

4.Never operate the MX855 on its side, as the cooling potential drops significantly when operated this way.

5.Connect the MX855 inputs to the source component outputs with good quality, short as possible RCA jack cables. Connect each channel individually.

6.Connect the MX855 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).

Note: Ideally the MX855 likes 6-8 Ω loads. Connecting to 4 Ω loads won't hurt the MX855 but those channels connected to 4 Ω loads may occasionally shutdown due to overloading. Never connect to speaker loads less than 4 Ω. Channel 4 bridged mode minimum 8 Ω speaker.

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

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 trigger if being used to a 12 VDC source (about 35mA) using a 3.5mm mono jack. 5 VDC triggers will not work.

10.Connect the AC power into an outlet that supplies at least EIGHT amps (1000 watts) dedicated to each MX855.

11.If more power is needed, channel 4 can be mono bridged to give 180 watts into an 8 Ω load. Minimum impedance for channel 4 in the bridged mode is 8 Ω. The bridged switch needs to be in the out position. The bridged input is 4L and the 4L gain pot adjusts the bridged gain. The speaker is connected to the 4L+ and 4R+ in the bridged mode.

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Knoll MX855 specifications Knoll Systems service information, Installation, Troubleshooting, Problem Action

MX855 specifications

The Knoll MX855 office chair is a remarkable seating solution that embodies modern design, ergonomic support, and advanced technology, making it a preferred choice for professionals who spend long hours at their desks. Designed with both aesthetics and functionality in mind, the MX855 is ideal for contemporary workspaces.

One of the main features of the MX855 is its adjustable ergonomic design. The chair is equipped with a dynamic lumbar support system that adapts to the user's spine, providing essential support to prevent discomfort during extended periods of sitting. The seat height, depth, and armrests are fully adjustable, allowing users to find their optimal seating position for maximum comfort.

Another significant aspect of the MX855 is its innovative mesh backrest. This feature not only contributes to a sleek and modern appearance but also enhances breathability, ensuring that users remain cool and comfortable throughout the day. The mesh material promotes airflow, reducing the likelihood of sweat buildup and discomfort, especially during warmer months or in heated office environments.

The MX855 also boasts a sophisticated mechanism that allows for smooth recline and tilt functions. Users can easily adjust the tension of the recline to suit their individual preferences, enabling seamless transitions between work and relaxation. This feature supports a range of postures, encouraging active sitting which can improve productivity and reduce fatigue.

Additionally, Knoll incorporates sustainable materials in the MX855's construction, reflecting a commitment to environmental responsibility. The chair is designed with durability in mind, featuring high-quality components that ensure longevity and reduced waste.

The aesthetic appeal of the MX855 cannot be overlooked. Its sleek lines and minimalist design make it an attractive addition to any office environment, seamlessly blending with various interior styles. The availability of different colors and finishes allows for customization, enabling organizations to match their branding or design preferences.

In conclusion, the Knoll MX855 is a state-of-the-art office chair that combines ergonomic support, innovative technologies, and stylish design. With its adjustable features, breathable mesh backrest, and commitment to sustainability, the MX855 stands out as a top choice for those seeking comfort and functionality in their workspace. Whether in a corporate setting or a home office, this chair is designed to enhance the user experience, making it an investment in health and productivity.