Alphasonik PMA640HCE Stereo Amplifier User Manual


 
Turning On The Amplier
The amplier automatically turns on a few seconds after you turn vehicle’s igni-
tion switch to ACC ON or turn on your auto sound system, depending upon how
you wired the system. The POWER indicator on the top of the amplier illumi-
nates when the amplier is on.
Important: Your amplier requires 90 amps or more of power from your vehicle’s
battery during operation. To protect your battery from your battery from discharg-
ing, do not operate the amplier unless your vehicle us running.
Adjusting The Audio Level (“Gain Matching”) By Ear
For best performance, you must match the amplier’s input sensitivity to your
source unit’s maximum output level. The GAIN CONTROL (MIN / MAX) located
on the side of the amplier is designed to do this. It is Not a volume control. It
adjusts the incoming signal level so that the source unit and amplier reach
maximum output at the same time. This assures that maximum system is
achieved with minimal distortion.
1. Turn the GAIN CONTROL (MIN / MAX) fully counterclockwise to MIN.
2. Play full frequency music that has continuous high levels (FM pop music is a
good choice).
3. Turn up the source unit’s volume control until just before you hear the source
unit’s distortion or 90% of full output (which ever comes rst).
4. SLOWLY turn the GAIN CONTROL clockwise until just before you hear ampli-
er or speaker distortion, until you reach a maximum comfortable listening level
(which ever come rst).
5. Turn the source unit’s volume control back to a desire comfortable listening
level and enjoy.
Note: Raising the LPF frequency allows higher frequencies to reach the bass
speakers while blocking lower frequencies from midrange speakers. Lowering
the LPF frequency allows lower frequencies to reach the midrange speakers
while blocking higher frequencies from bass.
+ 10dB
+ 20dB
0dB
- 10dB
- 20dB
- 30dB
10 50 100 500 1K 5K 20K 50K
RESPONSE (dB)
FREQUENCY RESPONSE BASS BOOST ON
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