Short Circuit Protection; Thermal Protection - YORKVILLE Professional Serie Manuel De L'utilisateur

Ground Switch
Switching the ground switch on the rear panel will
disconnect chassis ground from circuit ground. Safety
(earth) ground is still connected to the chassis. We do
not recommend lifting the ground strap unless you are
experiencing problems with ground loop hum in mul-
tiple amplifier setups where lifting the ground straps of
all but one amplifier cures the hum problem.
CAUTION: Sometimes hum problems are an indication of
improper AC wiring somewhere else in your system. Don't
just doctor the symptom by lifting grounds. Fix the cause
by making sure that the proper electrical wiring safety
regulations have been adhered to.
Modes
The AP6040 can be configured for dual-MONO or
STEREO operation via the rear panel MODE switch. The
following is a description of each mode:
Mono Mode
• Channel A and B inputs are paralleled.
• Each gain control adjusts the signal level for its
respective channel,
• Output signals are of equal phase.
• Two loads are driven.
• Loads are connected between the BLACK and
RED post on each channel.
Stereo Mode
• Two independent amplifiers, Amp A and Amp B.
• Two loads are driven.
• Loads are connected between the BLACK and
RED posts on each channel.
Subsonic Filter Switch
The AP6040 features a specially designed subsonic filter
which effectively blocks potentially destructive energy
in the band below 40 Hz. The filter provides a 12 dB/
octave. skirt below 40 Hz. It is implemented with a two
pole network designed to minimize phase shift down to
40 Hz. We recommend using this filter in conjunction
with some subwoofers and with all high power full range
cabinets. With the filter disabled, the AP6040 is flat down
to 20-Hz, and rolls off at 12dB/Oct below that.
CAUTION: The AP6040 can deliver over 2000 Watts of power into a speaker load. Yorkville's own high power speaker
systems have circuit-breaker protection built in. Although these speakers will protect themselves, they are unlikely to be dam-
aged by a AP6040. However, many other speaker manufacturers make "high power cabinets" with no protection features at
all.
Yorkville Sound is not responsible for any damage which may result as a consequence of exceeding such a speaker's power
handling capability. Yorkville's two year unconditional warranty does not cover any consequential damages to non-Yorkville
equipment. Please consider these facts carefully before you choose to run your AP6040!
2
Limiter Switch
With the internal limiters activated, the AP6040's gain
is continuously adjusted to fit the signal within the avail-
able dynamic range. Occasional clipping is permitted.
The limiters will not only help to protect your system's
horns and tweeters, but will automatically make the best
use of the available dynamic headroom. With the limit-
ers activated, all you need to do is turn up the signal
level until you start to see some clipping. The limiters
will make sure that you are getting the maximum clean
power output at all times. Setting the switch to the IN
position completely disables both limiters.
Protect LED
In the event of a shorted load or a load which is of
too low an impedance for the amplifier to handle the
PROTECT LED will flash alternately on and off at about
3 second intervals. The sound may come on and off
at ½ second intervals. In this case, the fault is in the
speakers or the speaker cables and should be located
and remedied. No reset of the AP6040 is required to
restore proper operation. The PROTECT LED will stay on
if the amplifier has overheated. Check the speaker load
impedance and any restrictions to air flow at the air
intake or exhaust vents of the amplifier.

Short Circuit Protection

The AP6040 is fully protected against all possible pas-
sive load conditions. It can operate into a dead short
continuously without damage. (However, we don't
recommend that you short your AP6040 "just for fun."
Shorts do create a lot of stress on the output devices).
The output stage uses a unique triple slope VI-limiting
scheme which is sophisticated enough to remain inert
during transient currents in excess of 100 Amperes and
phase angles of more than 45 degrees, yet is capable of
protecting the output stage from damage due to acci-
dental short circuits and improper loads.
DC Protection
In the unlikely event of the AP6040's outputs going DC,
a thyristor circuit will short the output terminals and
divert all potentially harmful currents away from your
speakers.

Thermal Protection

In the unlikely event that the AP6040 overheats, the
signal will be sporadically cut off and the PROTECT
LED will stay on. The AP6040 is designed and tested to
operate under "worst case" conditions without shutting
down, so if you experience a thermal shut down you
should check for blocked air flow.