3
12. Thermal Protection
In the unlikely event that the
A4.4
overheats, the signal will be sporadically cut off and the PROTECT LED
will stay on. The
A4.4
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.
13. Cooling
The fan draws air in from the front and expels hot air through the
rear vents. This is compatible 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.
14. Fan Filter Maintenance
The
A4.4
is factory equipped with a fan filter mounted on the air-intake grill located 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
depending 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.
15. Clip LEDS
The CLIP LEDS on the front panel will visibly indicate any signal excursion beyond the dynamic
headroom of the amplifier.
16. Reliability
The
A4.4
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 sophisticated computer controlled
equipment which is capable of identifying any deviation from the design center parameters. The design of
the
A4.4
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 reputa-
tion as a manufacturer of reliable equipment will be further enhanced by the
A4.4
.
The
A4.4
is not only suitable for use in both heavy duty touring sound reinforcement systems but also
when high headroom and low distortion are needed to fully reproduce the dynamic range and clarity of
today’s CD recordings. It is built to survive grueling road conditions and constant 4 ohm operation. Its reli-
ability in a fixed installation running 4 or 8-Ohm studio monitors is without parallel.
17. Output Connections
WARNING:
When driven to full power in Bridge Mode, there is more than 100Vrms appearing between the binding
posts. This represents a significant shock hazard and due care should be taken when making any speaker connec-
tions. Ensure that no strands of bare conductor are exposed after inserting the speaker wire into the hole in the side
of the binding post terminals.
The
A4.4
has 5–way binding posts and Neutrik four contact Speakon™ connectors for output speaker con-
nections. Connection to the binding posts can either be made with a banana plug inserted into the end of the
post, a spade connector or bare wires.
There are two Speakon™ connectors. The Speakons™ are connected to the amplifier’s outputs whether
the amplifier is in stereo, mono, or bridge modes. Each Speakon™ output connector (output A and output
B) is wired in parallel with it’s respective binding posts for two channel two cable connections (figure 1).
Speakon™ output A also doubles as the A & B/Bridge connector. This Speakon™ contains both chan-
nels on one connector. This is convenient when connecting one speaker to the amplifier in bridge mode
where the speaker is connected across the positives of each amplifier output. Configure the mode switch
for bridge and connect the speaker to pins +1 and +2 of the bridge/bi-amp Speakon (figure 3).
To connect a bi-amp speaker, configure the amplifier for stereo and connect to the bridge/bi-amp con-
nector but use all four terminals in the Speakon™ connector which will connect A and B outputs separately
to the speaker (figure 2). Connection configurations are labeled on the back panel.
YS Part #8381 Foam Filter
CAUTION:
The
A4.4
can deliver over
2400 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
A4.4
. 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 con-
sequence 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
A4.4
in Bridge Mode!
