YORKVILLE PROFESSIONAL Serie Manuel De L'utilisateur page 4

STEREO MODE
• Channel A and B inputs are separate.
• Two independent amplifiers, Amp A and Amp B.
• Two loads are driven.
• Loads are connected between the BLACK and RED posts
on each channel.
BRIDGE MODE
• Channel A and B inputs are paralleled. GAIN-B has no effect.
• Output signals are equal
in amplitude but oppo-
site in phase.
• One load is driven.
• The load is connect-
ed between the two
RED binding posts.
The BLACK posts are
not used.
Subsonic Filter Switch
The AP800 features a specially designed subsonic filter which
effectively blocks potentially destructive energy in the band below
40-Hz. The filter provides an 12 dB/Oct. 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 AP800 is flat down
to 6-Hz, and rolls off at 12dB/Oct below that.
Limiter Switch
With the internal limiters activated, the AP800's gain is continu-
ously adjusted to fit the signal within the available 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
limiters 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 maxi-
mum clean power output at all times. Setting
the switch to the OUT 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 in about 7 second intervals.
The sound may come on and off at ½ second. In this case, the
fault is in the speakers or the speaker cables and should be located
and remedied. No reset of the AP800 is required to restore proper
operation. The protect LED will stay on
if the amplifier has overheated. Check
the speaker load impedance, the posi-
tion of the load select switch, and any
restrictions to air flow at the air intake or
exhaust vents of the amplifier.
Short Circuit Protection
The AP800 is fully protected against
all possible passive load conditions. It
can operate with a dead short continu-
ously without damage. (However, we
don't recommend that you short your
CAUTION: The AP800 can deliver over 800 Watts of power into a bridged 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 damaged by a bridged AP800. 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 capa-
bility. 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 AP800 in bridged mode!
2
All manuals and user guides at all-guides.com
AP800 "just for fun." Shorts do create a lot of stress on the output
devices). The output stage uses a unique triple slope VL limiting
scheme which is sophisticated enough to remain inert during tran-
sient currents in excess of 40 Amperes and phase angles of more
than 45 degrees, yet is capable of protecting the output stage from
damage due to accidental short circuits and improper loads.
DC Protection
In the unlikely event of the AP800'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 AP800 overheats, the signal will
be sporadically cut off and the PROTECT LED will stay on. If further
heating occurs, (due to some malfunction), an internal thermal break-
er will interrupt the primary circuit. There is no visible indication of
this rare condition. The AP800 is designed and tested to operate
under "worst case" conditions without shutting down, so if you expe-
rience a thermal shutdown you should check for blocked air flow.
Cooling
The fan draws air in from the front and expels hot air through
the rear vents. This is compatible with our other amplifiers and
with most installations. Since hot air rises, the heated air forcibly
expelled from the back tends to rise away from the equipment
rack. This draws cool air from the floor upwards into the front of
the rack. In some cases where the rear of the rack is obstructed it
may be necessary to install rack fans to aid cooling. If there are no
obstructions, no secondary cooling is required.
Fan Filter Maintenance
The AP800 is factory equipped with a fan filter mounted on
the air intake grill on the amplifier's front panel. Regular cleaning
of this filter will increase the amplifier's long term reliability. The
filter should be removed and washed at the first sign of visible
clogging. This will typically occur every four to six weeks depend-
ing on use and environment. Replacement filters are inexpensive
and can be ordered through Yorkville dealers. The foam filter
should be removed if a regular inspection schedule is not going to
be followed. The amplifier can operate without the filter in place,
but the amplifier should be cleaned internally by a qualified ser-
vice technician when dust is visible on the heatsink fins.
Note: In an unusually dusty location, without regular filter
inspections, removing the foam filter can extend the operating
time before thermal shutdown could occur. At that time, the
internal heatsinks should be cleaned thoroughly.
Clip LEDS
The CLIP LEDs on the front panel will visibly indicate any signal
excursion beyond the dynamic headroom of the amplifier.
Reliability
The AP800 is designed and manufactured by Yorkville
Sound. Each unit undergoes a thorough, temperature cycled burn-
in period, and each circuit is tested by both manual and sophisti-
cated computer controlled equipment which is capable of identi-
fying any deviation from the design center parameters. The design
of the AP800 is conservative with respect to the power handling
capabilities of the output devices. The topology guarantees that
thermal stress not secondary breakdown will set the limits of
operation, while the computer optimized heat dissipation system
insures that excessive thermal stress will not occur. Yorkville's
reputation as a manufacturer of reliable equipment will be further
enhanced by the AP800.