Amplifier - Lightning Audio

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R E P O R t
Lightning Audio
LA-8004
TEXT AND MEASUREMENTS by GarRy Springgay
// Photos by Manufacturer
Amplifier
fter almost disappearing from the mainstream car audio marketplace for about a year, the Lightning Audio brand
has re-invented itself and is back stronger than ever with a series of competitive high performance amplifiers
and speakers. A subsidiary brand of Rockford Corporation, the Lightning Audio colors are again flying high and
proud at specialty independent car audio retailers all over the country. To show us what they’ve been working on, a top of
the line LA-8004 amplifier showed up here at the lab. We put it through the paces, and here is what we found.
A
FEATURES
The Lightning Audio LA-8004 is a conventional
Class AB four channel amplifier. But while the
internal topology may be conventional, there are
quite a few details that aren’t. First, at just 9.9” x
7.5” x 2.7”, the LA-8004 is a fairly compact unit,
especially when you consider that it is rated for
80x4 into 4 ohms, and 110 x 4 into 2 ohms per
channel. It has a sort of industrial look to it, with
smooth surfaces and rounded corners, finished in
a matte gray powdercoated top plate, with contrasting gloss black sides. The result is a purposeful looking amplifier, especially when it’s turned
on and the Lightning Audio badging is illuminated
from the backside in white light.
Unlike many of its competitors, the LA-8004
manages to place all of the wiring and signal
connections on one long edge of the amplifier,
which simplifies a tidy installation. The signal
controls are mounted under a clear removable
acrylic cover on the top of the unit. Top-mounted
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PERFORMANCE AUTO & SOUND – PASMAG.COM
controls like this are pretty handy when tuning,
allowing easy access to crossover and EQ tuning
controls without having to do a lipstand on the
floormat. Adjustments include 10Hz to 150Hz
high pass crossovers, and 30 to 150Hz low pass
crossovers. There are also separate bass EQ pots
for the front and rear channels, and a 2ch/4ch
input selector switch.
Power cable and speaker connections are handled by nicely finished, angled set screw terminals,
which will handle 8 and 12 gauge wire respectively,
but I’ll never understand why you need three
different sizes of hex wrenches to do the wiring
on an amp like this. Sure, they are supplied, but
a liberal application of the old KISS principle (Keep
It Simple, Stupid!) would be welcomed. Also on the
business side of the amplifier is a pair of 25A ATC
style fuses, 2 pairs of RCA inputs, as well as a pair
of pass through type RCA outputs.
Inside the LA-8004 I found a very nicely designed PCB with zero tolerance surface mount
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Lightning Audio LA-8004
TECHNICAL DATA
The following power measurements were obtained using industry standard methods.
(1kHZ @ 1.0% THD+N - Battery voltages shown +/- 0.2V)
MEASURED PERFORMANCE SPECIFICATIONS
parts used wherever possible. Crossover
distortion is eliminated by individual channel
bias pots, instead of compromising performance with a cheaper fixed resistor. Four high
current MOSFETs are used for power supply
switching, and each channel uses a matched
pair of MOSFET devices as outputs. A total
of twelve 1000µF caps are used, four for the
power supply storage, and the remaining
eight to stiffen the output rails. The amplifier’s controls and switches are mounted on
a daughterboard that floats longitudinally
over the main PCB. Build quality looks very
good and the amplifier uses high quality
components throughout.
LISTENING
With the LA-8004 driving a pair of component speakers with the front channels, and a 4
ohm 12” subwoofer bridged to the rear channels, I made a few adjustments to the crossover
and gain, and did some critical listening. The
new flagship multi-channel amp did a very good
job driving my loudspeakers, and proved to have
plenty of power for all but the most enthusiastic volume levels. The amplifier sounded
quite transparent and clean, and it was also
dead quiet between tracks or during very soft
passages. Bottom end response was fat and
warm sounding, with good authority. The bass
may have been just ever so slightly muddied,
but to be fair, I’m talking about seeds and stems
here, not likely the kind of thing you’d even
notice while driving down the road. I played all
sorts of music through the LA-8004 for about
3 hours, and during the entire time did not note
one complaint with its performance. It did get
good and warm during my listening session, so
I’d make sure this amp gets mounted in a well
ventilated area if you plan on using most of the
power it makes available.
Lightning Audio
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PERFORMANCE AUTO & SOUND – PASMAG.COM
Manufacturers
Rated Power
Actual Measured Power
@ 1.0% THD+N
@ 12.6V Battery
Actual Measured Power
@ 1.0% THD+N
@ 14.4V Battery
80 x 4 @ 4 Ω
61 x 4 @ 4 Ω
81 x 4 @ 4 Ω
110 x 4 @ 2 Ω
85 x 4 @ 2 Ω
112 x 4 @ 2 Ω
220 x 2 @ 4 Ω
172 x 2 @ 4 Ω
224 x 2 @ 4 Ω
Signal to Noise Ratio referenced to 2V output. (CEA-2006A) (1 watt
@ 4 ohms)
-83.7dBA
Signal to Noise Ratio referenced to full output.
-102.8dBA
THD+N at rated 4 ohm power
1.0%
CEA-2006A rated 4 ohm Power (minimum power per channel
developed over the entire intended audio bandwidth)
77 Watts
Maximum Efficiency at full 4 ohm power per ch.
64.1%
Maximum Efficiency at full 2 ohm power per ch.
53.3%
Efficiency at 10 watts per channel, 4 ohms
21.7%
Idle Current
0.9A
Input Sensitivity
180mV- 5.6V
Maximum Current @ full power, lowest rated impedance
58.4A
Frequency Response (-3dB)
<10Hz – 89kHz
High Pass Crossover
Low Pass Crossover
10Hz – 150Hz
-12dB/Oct
30Hz – 150Hz
-12dB/Oct
Subsonic Filter
None
Bass Boost
0 to +9dB @ 45Hz
PERFORMANCE / BENCH MEASUREMENTS
On the bench, the LA-8004 met the power specifications found in the online owner’s
manual, but without a lot of power headroom, coming in at just a couple of watts over
rated power. Signal to Noise ratio was very good, as I had expected it to be from the
listening session. Being a Class AB amplifier, overall power efficiency isn’t its strong suit,
but then again, it’s a lot less money than most of the ultra efficient Class D four channels
available. While measuring the crossover functions, I found out that the high pass filter
is also engaged when the amp is in low pass mode, so something of a low frequency
bandpass filter can also be arranged. The amplifier has well-designed protection circuitry
for thermal, short circuit, and high battery voltage conditions. I would deliberately cause
a fault, and the amp would simply protect itself until the fault was corrected.
CONCLUSION
Priced right around US$349.95, the new Lightning Audio LA-8004 amplifier is
a well-made, quality product that delivers good power, great sound, is compact enough to
be easily installed and looks good too. To find out more about the LA-8004 and all the other
new Lightning Audio products, visit them on the web at www.lightningaudio.com
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www.lightningaudio.com