Jensen POWER 400 - POWER 400 AMPLIFIER, Installation And Operation Manual

POWER Amplifiers

10

Indicators and Controls

Power Indicator (POWER)

The power indicator provides a visual indication that the amplifier is turned on.

Input Level Control (LEVEL)

The input LEVEL control matches the output of your radio to the input of the 
amplifier. After the installation is complete, make sure the input level control on 
the amplifier is turned down all the way (counter-clockwise or all the way to the 
left). Play a tape or CD (make sure bass and treble settings or Bass EQ are 
flat) and turn the volume up slowly until you just start to hear distortion. Back 
the volume down just a bit. On the amplifier, slowly turn up the input level 
control (clockwise or to the right) until you just start to hear distortion, then 
back it down a bit. Now your radio and amplifier levels are matched.

BASS EQ

The Bass EQ is continuously adjustable from 0 to +12dB @ 45Hz. Adjusting 
the Bass Boost level allows different subwoofer/enclosure combinations to be 
equalized. Use this control to increase the level of low bass available from your 
subwoofer/enclosure combination. Ported and Band Pass enclosures should 
be limited to about +6dB to +9dB of boost. Sealed enclosures should be able 
to accept the full +12dB of boost, if necessary. The full +12dB of boost should 
be reserved for special applications since improper use of the Bass Boost 
could damage your subwoofers at high volumes.

Low Pass Filter (LPF)

The Low Pass Filter controls adjust the crossover point. Typical crossover is 
between 60Hz and 80Hz for ported and sealed enclosures. Bandpass boxes 
will typically use a higher crossover setting between 125Hz and 150Hz. Since 
musical tastes vary, you should play music that you would normally listen to in 
your vehicle, with the above settings as a starting point. If necessary, set the 
crossover by ear.

High Pass Filter (HPF)

The high pass filter will limit the low frequencies being transmitted to your 
speakers. This can be useful in number of situations. For example, if you 
selected the high pass filter and set the crossover to 40Hz, then you would 
have an infra-sonic (sub-sonic) filter at 40Hz, which would be useful with 
certain enclosure/subwoofer combinations that were tuned between 45Hz and 
50Hz. Other uses might include limiting the low frequencies to smaller 

speakers (6 1/2", 6 X 9", etc.) by adjusting the crossover to a higher setting 
(80–100Hz).

Crossover (X-OVER)

The Jensen Power series of amplifiers have built-in low-pass and high-pass 
crossover filters for bi-amplifying the system. Adjust the crossover to 
accommodate your chosen installation method. Select LPF (low pass filter) 
when the amplifier will be driving woofers or subwoofers. Choose FULL when 
crossover mode is not active and the amplifier is in “full range” mode. Select 
HPF (high pass filter) when the amplifier will be driving full-range or separate 
speakers, and you want to limit the “bass” being transferred to these speakers.

Mode Switch

Power 400.2

The 400.2 comes equiped with a MONO/STEREO MODE switch. Use 
STEREO mode when you have a 2-channel input from the source unit. Use 
MONO mode when you have a single input from the source unit. See “Input 
Wiring” on page 8.

Power 760.4

The 760.4 comes equiped with a 2/3/4 MODE switch and can be configured for 
three different input modes: 2 channel, 3 channel or 4 channel.