Knoll 21K Stereo Amplifier User Manual


 
Hum and noise
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.
Potential ground loops in a complex A/V system
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 our 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.
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
with any sophisticated device, there may be occasional
problems upon initial installation, or during the life of the amp.
The items on the list below are a brief guide to the minor
problems that you may be able to correct yourself. If these
solutions do not help, or if the problem persists, contact us for
assistance.
Problem Solutions
Amplifier won’t turn on Master power switch turned off (No
power light LED). Turn on Master Power
Switch.
Amplifier won’t turn off Remote trigger cable not properly
connected. Verify connection of trigger
cable at both ends.
Amplifier turns on, but no Input plugs not connected to proper
audio from one or more jack or are loose. Check input
channels connections.
No audio from one or more Speakers are not connected
channels properly. Check speaker connections at
amp and speaker.
Audio levels differ Improper settings or output levels
from source device. Check the settings on your preamp,
processor or controller. Also verify
settings of the rear panel gain controls
on your amp.
Audio plays and then cuts off Amplifier may be shorted. Check
speaker connections for short-circuit at
amp and speaker.