Level Setting - Soundstream Reference Series 644S Installation Manual

INSTALLATION STEP 5

LEVEL SETTING

The input levels are adjusted by means of the individual channel input level
controls located on the front of the amplifier. This is a unique dual-stage
circuit that adjusts both level and gain. This topology maintains better Signal
to Noise ratios even when using sources with minimal output.
In the ideal situation, all components in the audio system reach maximum
undistorted output at the same time. The reason is because an amplifier will
only make what comes into it bigger. So, if you send it a distorted signal from
the head unit, the amplifier is going to amplify distorted information.
same thing holds true if an outboard processor or crossover begins to distort
before you have maximum output from the amplifier.
components to reach clipping at the same time, you can maximize the output
of your system. For the REFERENCE644s amplifier, follow the steps below
for the quickest, easiest means of setting the levels.
1. Turn the amp's input levels to minimum position (fully counter-
clockwise). If any channel is in low pass mode, set the subwoofer level
pot to the 0 dB position (12 o'clock).
2. Begin with the input level switches in the 0.5 - 5.0 Volt position.
3. Set source unit volume to approximately 3/4 of full volume.
4. While playing dynamic source material, slowly increase the amplifier's
input levels until a near maximum undistorted level is heard in the
system.
5. If you can't get enough gain out of the amplifier, set the input level switch
to the 0.2 - 2.0 Volt position, and repeat steps 3 and 4.
6. If any channel is in low pass
mode, you may have to adjust
NOTE: It may be necessary to adjust
the balance between low and high pass
levels after listening to the system.
These settings are dependent upon
personal preference.
If your preamplifier / source unit has an extremely high output level, be sure to
pay attention to the clipping indicators located on the top of the amplifier.
These indicators will notify you if you are clipping the PREAMPLIFIER stage of
the amplifier. If the amplifier's output is distorted and the clipping lights are
not blinking, you are most likely clipping the OUTPUTS of the amplifier, or
driving the speaker to distortion.
There is an additional control for subwoofer level adjustment. The purpose of
this control is to provide additional range of adjustment for the subwoofer
signal in relation to the high pass signal. This control adjusts the level of any
By setting all
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INSTALLATION STEP 3
POWER AND GROUND
To ensure maximum output from your REFERENCE644s amplifier, use high
quality, low-loss power and ground cables. The REFERENCE644s amplifier
will accept up to 4 gauge power and ground cables. Determine from the chart
REFERENCE644s
The
The Soundstream REFERENCE amplifiers have extensive internal power
supply capacitance, called the Ultra-Low ESR Capacitance Bank. Multiple
small input power capacitors act as an internal "stiffening capacitor". Because
of the large amount of internal capacitance, there may be a sizable spark
when connecting the power and ground lead to the amplifier for the first time.
In order to charge the capacitor bank without a spark, we suggest you do the
following:
1. Connect the +12 volt cable to the amplifier and to the battery.
2. Connect one end of the ground cable to the chassis of the vehicle.
3. We have supplied a 150 ohm, 2 watt resistor with the amplifier. One leg
of the resistor has been connected to the ground terminal of the amplifier.
4. To charge the capacitor bank, touch the loose end of the ground cable to
the open leg of the resistor for at least 45 seconds.
CIRCUIT BREAKERS/FUSES
EXTERNAL
Like all audio components, the REFERENCE644s amplifier must be fused
near the battery. A fuse or circuit breaker must be located within 18" of the
battery. This will prevent a fire in the event of a shorted cable. See the chart
on the next page to determine the correct fuse value.
INTERNAL
The REFERENCE644s amplifier is fused with automotive-type fuses. In the
WIRING
up to 10'
Soundstream Power40 or
Power80
Read this, or sparks will fly!
11
up to 20'
Soundstream Power40 only
(4 ga.)
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