AT500NC Manual
Rev-10/17
process is complete, the front panel switch will illumi-
nate fully, the
STANDBY LED
will turn off and the
amplifier will enter playback mode. To turn the unit
off, press the Power button again. The power switch
indicator light will dimly illuminate and pulse slowly.
Automatic On
Make certain that the connection to the controlling de-
vice is correct. Whenever the controlling device is
turned on, the amplifier will automatically turn on after
a short pause. This pause is intentional, and it protects
your speakers from damage while the amplifier stabi-
lizes. You may also hear a relay click as during start
up. This is also normal.
To turn off your amplifier, simply turn off the device
feeding the amplifier it’s audio signals. The amplifier
will automatically go into a standby mode in a few mo-
ments.
Peak Indicator Light
This indicator circuit continually monitors the output
level of your amplifier. This light will come on if the
amplifier exceeds its maximum output capability on
any channel. While this will not harm the amplifier, it
does warn of potential harm to your loudspeakers if the
light stays illuminated continuously for more than ten
seconds. The volume setting from your preamp or
source device must be turned down if this occurs.
AC Line Connector and Power Cord
Your amplifier is supplied with an internationally ap-
proved (IEC) power line connector that accepts the sup-
plied detachable, high-current capacity power cord.
WARNING:
Under no circumstances should the round
third prong on the plug be cut, bent or in any other way
defeated as this may result in severe shock.
WARNING:
Always turn off the amplifier and unplug
the power cord before making any electrical connec-
tions.
ATI Service Information
The AT500
NC
series does not contain any user service-
able parts inside. If you suspect a problem that may
require service assistance, contact us at support@ati-
amp.com, or by phone at 323-278-0001. It is important
that only an authorized service agent carry out any re-
pairs. This will assure proper service and preserve the
protection of your Limited Warranty. Keep your sales
slip or receipt in a safe place with this manual so that it
will be available to verify the purchase date, should you
experience a problem covered by out warranty.
8
Care and Maintenance
Cleaning
When the unit becomes dirty, wipe it with a clean, soft,
dry cloth. If necessary, first wipe the surface with a soft
cloth slightly dampened with a mild soapy water, then
with a fresh cloth dampened with clean water. Wipe
dry immediately with a dry cloth. Never use benzene,
thinner, alcohol or any other volatile cleaning agent. Do
not use abrasive cleaners, as they will damage the fin-
ished of the metal parts. Avoid spraying insecticide,
waxes, polishing agents, or any aerosol product near
the unit.
A Few Words About Hum and Noise
Audible hum, or a discernable low frequency noise, is
one of the most common problems in audio/video sys-
tems. This hum, which may be present even when the
volume is at a low level, is usually caused by a problem
known as “ground loops”. A ground loop occurs when
there is a difference in ground voltages between two or
more components that are connected electrically. This,
in turn, creates multiple current paths and causes the
low-level noise, or hum.
The growing sophistication and complexity of home
audio/video systems, and the increased number of com-
ponents used to create these systems has dramatically
increased the potential for the possibility of ground
loops. While it is natural to suspect that the components
in your system are the cause of the hum, in many cases
the cause may be due to other conditions. In particular,
cable TV connections from outside the house have be-
come a major source of hum.
In most cases, one of the following suggestions should
help you to solve a hum problem in your system. Please
try these steps in the sequence 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 all components off. 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 before reconnecting the cable TV
feed, or contact your cable TV operator to see if they
can better isolate your cable feed.
