TECHNICAL DESCRIPTION
In order to reach the high line level voltage desirable at the output of the
PA-II
©
,
and to isolate the preamp from the vehicle's electrical system in the interest of
eliminating noises, a self-oscillating power supply is employed. The power supply
operates at an ultrasonic frequency and provides a 30-volt split supply to power
the circuitry involved.
The
PA-II
©
incorporates a double-sided fiberglass epoxy circuit board to help
keep the size to a minimum, to insure years of trouble free operation, and to
allow us to build a preamp equalizer with incredible bandwidth without fear of
oscillations or noise.
The
PA-II
©
has reverse polarity protection, and can be adjusted to accept input
levels from 150mV to 5V while providing up to 5V of line level output. The
dynamic capability of your source is greatly affected by the loading effect
presented by the input impedance of an amplifier. The input and output
impedances of the
PA-II
©
were carefully chosen to optimize the transfer of
information from source to amplifier without sonic degradation. The load is taken
off of your source and placed on the very strong output buffer preamp in the
PA-
II
©
. The four bands of equalization were carefully chosen to provide help in the
regions of a car audio system that most often have problems.
The low bass area is the most troublesome in most installations. Even the best
low frequency speakers being used in the mobile environment tend to roll off too
soon, leaving a void at the low end of the spectrum. The Sub Bass control on the
PA-II
©
is centered at 45 Hertz, providing the ability to boost the real low
frequency information missing most often.
The Mid Bass control is fixed at 180 Hertz, and provides a chance for the
removal of some of the extra information built up by the natural resonance of the
average vehicle.
The Midrange control follows a curve that matches the response characteristics
of the human ear. This allows the system's overall sound balance to be set to
where it sounds natural.
The High frequency control is set at 16 Kilohertz. This gives you the ability to
bring up the output of the tweeters at a point where most are rolling off.
© 2008 Linear Power, Inc. - ALL RIGHTS RESERVED
LINEAR POWER™ is a trademark of Linear Power, Inc.
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