Krell Industries 350Mcx - Manual (Page 21)

Krell Full Power Balanced X Series Power Amplifiers 17
HOW TO TROUBLESHOOT
SYSTEM NOISE
AC grounding becomes critical when connect-
ing high performance audio components. When
you mix and match audio components, each
with its own ground potential, a low frequency
hum may occur in one or both speakers. This
often occurs when introducing a new compo-
nent into a system.
If a low frequency hum emanates from the
speakers when you place the Full Power Bal-
anced amplifier into the system, follow these
simple troubleshooting steps:
Note
During these steps, the back panel power
breaker switch remains in the on position.
1. Check all input and output connections,
making sure they are of sound construction.
With the amplifier in stand-by mode, remove
the interconnect cables, then press the front
panel power button. If the hum disappears,
press the power button to return to stand-by
mode, and reinsert one of the interconnect
cables. Press the power button again. If the
hum reappears with one or both intercon-
nects inserted, there may be a defective
cable. Have the interconnect cables checked
before proceeding.
2. If the interconnect cables are sound, you
may be experiencing a ground loop. This
can often be easily eliminated. Please con-
tact your authorized Krell dealer, distributor,
or Krell for suggestions on how to solve this
problem.
HOW TO EVALUATE AMPLIFIER
OPERATION
The amplifiers are protected by a series of non-
intrusive circuits that constantly evaluate the
amplifier’s operation. This circuitry protects
against damaging DC input or output and short
circuits, see also DC Protection Circuitry, on
page 14, and monitors regulator operation,
ensuring constant voltage to the output stage.
The protection circuitry in a Full Power Bal-
anced amplifier is designed to prevent damage
to the amplifiers or speakers caused by other
defective components, faulty wiring, system
mishandling, or amplifier failure.
In addition, when a Full Power Balanced ampli-
fier’s DC protection circuitry senses a problem
within the system, it identifies, then indicates the
problem by illuminating the front panel blue
LEDs, as described in the following table.
Notes
The Krell CAST LED illuminates only if a Krell
CAST input is being used.
There are no output fuses in Full Power Bal-
anced amplifiers.
Amplifier Troubleshooting