background image

 
When installing, make sure the 21k front panel power switch is 
in the out or “OFF” position. Plug the DC adapter into a switched 
outlet on the source device that will be activated when you want 
to have the amplifier turn on. This may be the switched outlet at 
the rear of an AC receiver or other audio equipment. Connect 
the 3.5mm mini-plug from the adapter to the trigger-input jack 
on the back panel of the amplifier. The amplifier now turns on 
and off automatically, based on the status of the controlling 
device. 
 

Power connection

 

Once all audio system connections have been made, connect the 
supplied power cord to the amplifier first, and then connect it to 
an AC power source. Please make certain that the amplifier is 
turned off and that the device connected to the remote trigger 
input is off when connecting the power cord and plugging it into 
an AC outlet. 
 
 

Amplifier operation

 

After all connections have been made you are ready for 
operation. First, turn on the source component in your system.  
 
 

It is always a good idea to turn on your amplifier LAST.  

 
 
This avoids the possibility of any turn on pops or transients from 
other equipment being amplified and sent to your speakers 
where they may cause damage. Always start with a low volume 
level on your computer or preamp to avoid damage to your 
speakers. 
 

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 (out position). The amp will turn off in a few seconds. 
 
 

Ga in

L R

L

R

IN     O UT

Le ft

R ight

Bridge switch must be in OUT postion.

Connect speakers to RED terminals.

Minimum speaker impedance is
six (6) ohms.

Power
connection.
Observe
correct
voltage.

Speakers

21K

High Current
Power Amplifier

  Power
   8  A
12 0 VAC
~ 6 0 Hz

 2-16 OHM
SPEAK ERS

BRI DGE
 (OU T)

-

+

+

-

S OURC E

1 2 VDC 45 mA
 Tri gg er In put

 

 

Bridge Mode 

The 21K can be put into the mono bridge mode to increase the 
power output.  
 
To do this, first make sure the 21K is powered down or off. 
Speaker damage could occur if it is powered up. 
 
Connect the source RCA jack to the left input. The left RCA 
source output can be sent to another amplifier input. 
 
Make sure the bridge switch is in the out position. 
 
Connect the speaker (minimum 6 ohms) to the two red speaker 
terminals on the 21K. The left red terminal on the 21K is 
connected to the speaker positive (+) input. The black 21K 
speaker terminals are not connected in the bridge mode. 
 
Turn the Left gain on the 21k all the way down (counter 
clockwise). 
 
Turn the source on and the power to the 21k and adjust the Left  
gain as desired. 
 
Enjoy.  
 
 

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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