Hafler XL-600 Owner's Manual - Grounding
Grounding
The XL-600 employs a common ground between the two
channels, which, for the input, is connected directly to
chassis, and for the output, is connected to chassis through
a 5 ohm thermistor to avoid ground loops. This common
ground allows the use of external devices which also have
common grounds, such as headphone or speaker switch-
ing boxes. Make sure that the “-", or black terminal of the
amplifier is connected to the corresponding terminal of the
accessory device.
OPERATION
Power Switch and Pilot Lamp
The red bar above the power switch will glow when the
power is switched on unless excessive, long term, heat
sink temperature has opened a thermal breaker, or the AC
line fuse has blown. If the unit has tripped off thermally,
reduce the input signal to avoid high turn-on level. The red
pilot bar will light a few seconds before operation is auto-
matically restored if the XL-600 has cooled down and the
power switch is left on.
If a second shutdown occurs,
check for inadequate ventilation, continued excessive
input signal, or a severely reduced load impedance.
Belayed Turn On and Protective Relay
To avoid the turn-on transients generated by some
preamplifiers, the XL-600 provides a 3 second delay before
a relay connects the output terminals, If your preamp
requires a longer delay period, consult the factory on
extending the delay. The relay will also disconnect the
load if significant DC is present at the output, or if the short
term heat sink temperature becomes excessive, while
allowing the fan to continue cooling the amplifier.
5