Unbalanced Inputs
The
SR300
will accept an unbalanced 1/4" connector, however the benefit of balanced inter-
connection will be lost.
Mono Operation
The
SR300
may be operated in mono by plugging into either of the inputs. This signal will be sent to
both amplifiers. Each amplifier will be controlled by its corresponding level control. You cannot use the
remaining input jack to "loop through" since the amplifier will take this jack as the input for that
channel
.
To connect a bi-amp
able
speaker, configure the amplifier for
ste r eo
and connect to the
appropriate
connector
s.
(e.g. CH A For the Low frequencies and CH B for the High frequencies.)
Short Circuit Protection
The
SR300
is fully protected against all possible passive load conditions. It can operate with a
“dead” short continuously without damage. (However, we don’t recommend that you short your
SR300
“just for fun”). Shorts do create a lot of stress on the output devices. The limiting allows for up
to 30 degrees of phase shift at 4 ohms or a load impedance of 2.6 ohms with no phase shift.
Cooling & Thermal Protection
The
SR300
protects itself against over temperature operation by advancing the current limit
until the power output is limited to a safe operating point. With the limiter engaged the level
will drop to prevent distortion. This will not occur except at very high temperatures. If the
SR300
is to be used for continuous operation at maximum output and into 4 ohms the installer
should ensure that adequate ventilation is provided.
Clip LED’s
The clip LED’s on the front panel will visibly indicate any signal excursion beyond the dynamic
headroom of the amplifier.
Signal LED’s
The signal LED’s will indicate that a signal of low listening level is reaching the amplifier. This
is useful when troubleshooting the system. If the LED’s are active and no signal is heard from
the speakers then the speaker wiring or the speakers are not working. The activity LED’s are
connected after the level controls, the level controls must be up for the LED’s to light.
Limiter LED’s
The limiter LED’s indicate that the limiter has reduced the gain of the amplifier. If the limiter is
engaged but the signal level is below the threshold and the amplifier is not clipping the limiter
LED’s will not light. This is the normal mode for reference monitor operation.
The limiter in the
SR300
serve a dual purpose, keeping the signal level below clipping and
preventing excessive continuous power from damaging the speakers. The operation is fast for
clipping prevention and slow for continuous power. The continuous power limit is 30 watts
into 8 ohms. With normal music the amplifier can easily reach clipping without exceeding this
limit. Use of the limiter in conjunction with the filter will prevent the most common damaging
signals from reaching the speakers. Current limiting due to over heating or incorrect loads will
also trigger the limiter just like clipping.
In applications where it is desired to operate the amplifier at full output the input can be
driven about 6 dB higher than required to reach clipping and the limiter will automatically
adjust the gain to maintain full output.
Setting the limiter switch out will disable the limiter action. This will not however disable the
current limit circuit that protects the output devices.
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