Line Level Audio Input
CAUTION! THE AMPLIFIER MUST BE OFF WHENEVER YOU MAKE CHANGES
TO THE INPUT CONNECTIONS.
Cascade Audio Outputs
The "Cascade Audio Outputs"enable you to connect another amplifier to your
preamplifier output. The connectors are gold-plated RCA phono jacks. Connect
them to another amplifier’s inputs with a standard audio patch cable. The outputs
are not buffered; if you wish to daisy-chain more than 5 Niles amplifiers you will
need a Niles ADA-6 buffered distribution amplifier. A single ADA-6 will allow
you to daisy-chain 5 amplifiers from each of its six outputs, allowing 30 SI-245
power amplifiers to be fed from the same master preamplifier. If your preamp has
a vacuum tube output stage, you must use a Niles ADA-6 to drive more than a
single SI-245.
STEP
1. Label all of the interconnecting
cables for the sources they connect to.
2. Connect the sources by inserting the
RCA plugs into the amplifier’s jacks.
DESCRIPTION
Use audio patch cables with RCA phono
plugs attached to the ends.
Connect outputs from your sources to
inputs on the amplifier. Never connect a
source or preamplifier’s input (e.g., record
inputs) to the inputs of your SI-245.
13
INSTALLATION
Turn-On Modes
The SI-245 draws more current than a preamplifier’s switched AC outlet can safe-
ly supply. Also, your preamplifier may "thump" at dangerous volumes if the
amplifier is already on when the preamp turns on. It is usually best to turn the
amplifier on only when it is needed. The Turn-On Mode selector switch gives you
three options for turning the SI-245 on and off.
Constant - The auto turn-on circuitry is off. The front panel master power switch
operates the amplifier. In is "On", out is "Off".
Audio Sense - The master switch on the front panel must be in the "On" position.
The amplifier is off when there is no audio signal present at either the left or the
right input, but the sensing circuitry is on. The turn-on sensing circuitry looks for
a tiny amount of audio signal present at any of the audio inputs. If it detects a sig-
nal, the amplifier is turned on. Once the audio signal stops, the sensing circuit
waits three minutes, then turns the amplifier off.
3-30 Volt AC/DC Opto-Isolated Voltage Trigger - The master switch on the front panel
must be in the "On" position. The amplifier is off when there is no 3-30V AC or DC volt-
age detected at the trigger input. Once the sensing circuitry detects a voltage and a line-
level audio signal is detected at the input, the amplifier is turned on. Once the voltage
stops, the sensing circuit instantly turns the amplifier off. Voltage triggers can be sup-
plied by Niles automated switchers, some video projectors, some surround sound
processors, or something as simple as a 16 volt AC wall adapter (Niles XF00008) plugged
into the switched outlet of your stereo receiver. DO NOT USE A DC WALL ADAPTER.
The long discharge time of the DC adapter’s filter capacitor will delay the turn-off of the
amplifier.
If you are using a wall adapter or external power supply to provide the trigger, it
doesn't have to be very large (a minimum current capability of 2.5 milliamps for a
3 volt trigger increasing up to a minimum of 38 milliamps for a 30 volt trigger).
INSTALLATION CONSIDERATIONS
6
DS00284BMY-SI-245.qxp 6/27/05 2:14 PM Page 13