Transcript Amps - Pacific Audio Visual Institute

AMPS


An amplifier is any device that changes,
usually increases, the amplitude of an input
signal.
The “Input signal" is usually voltage or
current.
Clipping




When the input signal to the amp gets too hot the
output circuitry cannot keep up with the input
demands
This causes clipping to occur
Generally clipping will not cause damage to the
amplifiers but will cause damage to speakers,
especially high frequency drivers in a passive
cabinet
The odd flash of a clip light is ok but if it’s on
steady reduce the input.
Protect




Amplifiers have built in protection circuitry to
automatically stop them from being damaged
If an amp over heats it will go into “Protect Mode”
or “Thermal Protect”
The Amp will shut off its output in protection
mode
When the temperature decreases back to normal
operating range the amp will turn on the outputs.
Protect Cont.






If the amplifier feels very hot check to see if the fan is
working properly
Amplifiers also have short circuit protection.
If there is a dead short the amp will shut down its
output
A blown speaker can cause a dead short
If possible setup the amps so the protection and signal
lights can be seen from the FOH mix position or
monitor mix position
Keep them out of direct sunlight
Stereo

Two inputs, one for each channel, controls both
sides of the amp.
Parallel

Mono, one input controls both sides of the
amp.
Bridge Mono








Bridge mono mode combines two amp channels into one
mono, much more powerful amp channel. This is most
often used for subwoofers.
The advantage of bridge mono is that you have a much
higher power rating;
The disadvantage is that you have only one amp channel.
Amplifiers have separate stereo and bridged mono power
handling specifications.
Connecting speakers to an amp in bridge mono mode is
different from stereo mode.
Usually you connect a banana plug to the middle two
positive banana outputs. You must also flip the amp into
bridge mono mode, using dip switches on the back of your
amp.
Power is Approximately Quadrupled
Never switch to bridge mono mode when speaker are wired
separately to each output.