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speaker cones will be moving in, while others move out. This 
will cause indistinct or confusing imaging, and muddled and 
cloudy sounds. To avoid incorrect phasing or polarity, be sure to 
use wire that has distinct markings, colors, stripes, wording, or 
grooves on each side of the speaker cable. When making 
connections to the amp and speakers, follow a consistent 
pattern of using one side of the wire to the red terminals and 
the other side to the black. When using cable with markings on 
one side only, standard convention is to consider the marked 
side of the wire as the red, or positive (+) connection, and the 
non-marked side as the black or negative (-) connection.  
 
Next loosen the knobs of the amplifier’s speaker output 
terminals far enough so that they pass through hole is revealed. 
Follow the proper connection instruction for your system with 
regard to which terminals are used. Once the connections are 
made, twist the cap back so that the connection is secured but 
do not over tighten or use tools, as this may break the delicate 
wire strands and decrease system performance. 
 
If you are using spade lugs, connect them to the speaker wire 
using the manufacturer’s instructions, and then loosen the caps 
on the speaker terminals. Place lugs between the plastic cap 
and the back of the terminal. Be sure to observe proper polarity. 
Use your fingers to tighten to obtain a positive contact. 
 
When using banana plugs, connections may be made by 
inserting the jack affixed to your speaker wire into the hole 
provided on the rear of the colored screw caps on the binding 
posts. Before using banana –type jacks, make certain that the 
plastic screw caps are firmly tightened down by turning them in 
a clockwise direction until they are snug against the chassis. 
This ensures that the maximum surface area of the plug is in 
contact with the jack. Watch for proper polarity. 
 
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. 

 
 
Making rear panel connections

 

When connecting the amplifier to your source equipment, 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. Correct polarity connections 
are important to maintain proper speaker phasing. When 
making connections to the amp and speakers, follow a 
consistent pattern of using one side of the wire to the red 
terminals and the other side to the black terminals.  
 

Power control connections

 

The 21k amplifier features a built-in remote turn-on system that 
can automatically switch the amplifier on when another device 
in the system is switched on. 
 

Remote turn-on using products equipped with a low-
voltage trigger jack

:

 

Make sure the 21k front panel power 

switch is in the out of “OFF” position. Use an accessory cable 
with a 3.5mm mono mini-plug on each end to connect the 
trigger output jack on the rear of the source device to the 
trigger input jack on the back panel of the amplifier. The trigger 
needs to be 12 VDC and about 35 mA. When trigger power is 
switched on, the amplifier will automatically turn on at the same 
time. 
 

Remote turn-on using external AC to DC power converter

If your source device does not have a dedicated trigger jack, it 
is still possible to activate the unit for automatic turn on when a 
Switched Outlet is available on the rear of the source device. To 
control the 21k amplifier this way, you will need a small AC to 
DC power converter like our PS1202, capable of delivering 12 
volts DC and over 35 mA. The DC voltage should terminate in a 
standard 3.5mm type mini plug (this will have to be added to 
the PS1202). This type of converter may be obtained as a power 
adapter from many electronic retailers. 

Summary of Contents for 21K

Page 1: ...ome 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 warranty gives you specific legal rights You may have additional rights which vary from state to state Knoll products sold outside of the USA and Canada may be covered by warranties provided by an authorized Knoll distributor Please contact the d...

Page 2: ...e 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 tha...

Page 3: ...e Our engineers and designers spent years of pain staking research and testing to perfect the sound quality We hope you will appreciate this effort and enjoy the amp 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...

Page 4: ...r 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 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...

Page 5: ...rt 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 Speaker connections To ensure that the high quality signals produced by your amplifier are carried to your speakers without loss of clarity or resolution ...

Page 6: ...izes You may also hear a relay click during start up This is also normal To turn off your amplifier just turn off the device feeding the amplifier its audio signals The amplifier will automatically turn off which takes a few moments Gain controls Level adjustments may be made at the rear of the amplifier The circuitry in your new amplifier may be different from your previous one Check the output l...

Page 7: ...e 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 iden...

Page 8: ...kers 21k Manual on Press the 21k front power switch to the on position There will be a short pause from the time the power is turned on until power is applied to the speakers This is intentional and protects your speakers from damage while the amplifier stabilizes The red protect lamp will glow and when the amp is ready a blue light will switch on To turn the unit off press the power button again ...

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