Cerwin-Vega Mobile stroker s2000.1

test report
Cerwin-Vega Mobile
Stroker S2000.1
Text and Measurements by Garry Springgay
Photos by Cerwin Vega Mobile
while back we
reviewed the
Cerwin-Vega
V-Max subwoofer, and in
that review I talked briefly
about how the mobile
product arm of legendary
brand is under all new
management, by a group
of experienced industry
veterans who are totally
focused on car audio. This
group of folks eat, live, and
breathe the 12 volt business,
and in less than a year have
built two all new series of
amplifiers to complement
their “loud” speakers. This
time we’re going to have
a look at the cream of the
crop, from the top of the line
Stroker series, they sent me
a couple of their S2000.1
subwoofer monoblocks.
A
58
PERFORMANCE AUTO & SOUND – WWW.PASMAG.COM
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test report
Cerwin-Vega Mobile
Stroker S2000.1
filter is a must on an amp that gets sold
with so many woofers that work so well
in vented boxes. The development team
seems to have thought the product out
pretty well, and made sure that it was
designed to work in any application of their,
or anyone else’s, woofers.
So far, maybe you’re thinking, big deal,
it sounds just like every other Class D amp
out there, but that’s where you’d be wrong.
The Cerwin-Vega Mobile Stroker S2000.1 is
not a Class D amplifier. Like a good Class D
amp, it is however still highly efficient, and
very powerful. How was this accomplished?
The Cerwin-Vega Stroker S2000.1 is a Class
GH amplifier. A Class GH amplifier is not a
switching amplifier, and does not have to use
large internal filters to remove high frequency
switching noise. Although the Stroker amps are
bandwidth limited by a Low-Pass only crossover,
these types of amplifiers are commonly used
for full range applications as well. Class GH
amplifiers are a more efficient version of class
AB amplifiers, and employ several different “rail”
voltages in the amplifier. A special control circuit
switches back and forth between these rails as the
signal output fluctuates. This allows the transistors
to work in the highest efficiency portions of their
output almost all of the time. In this manner, the
amplifier increases its power efficiency by reducing the amount of “wasted” power at the output
transistors. These types of amplifiers are known as
“rail switching” and they have the ability to decrease
power consumption and increase overall efficiency
to levels within a few percent of those of Class D,
without the sonic handicaps. Why aren’t there more
of these types of amps? Well, the disadvantages to
Class GH amplification include development of a more
complex power supply, and sophisticated precise
control over the switching of the voltage rails must be
accomplished to minimize distortion.
60
PERFORMANCE AUTO & SOUND – WWW.PASMAG.COM
d BIG
parent thloaat dI h(2a ohms to
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a
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m
It was imp, even with a 4 ohm provided by
w
po er onp)tathe amount of author..it.yit’s very cool,
each am of amps was awesome . Overall, the pair
the pair is much power on tapt, the power availa
to have th
att woofer
ounded garnem
s
w
s
0
p
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m
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a
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le
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it was fun to play
the
LISTENING
on
e
s
th
d
wa
te
it
ed that
tests, I connec
EQ. I sort of wish
For my listening
I’m
t
er
bu
of
el,
wo
e
of only lev
s to my referenc
remote instead
pair of S2000.1’
on
ct that
fa
e
th
ned to the cann
ed
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the master ampl
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and I only had to
one of the few tim
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slave amplifier,
of
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the one amplifier
is
th
It
.
ve
ps
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for the pair of am
amps. It’s very co
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control worked
d BIG
ha
I
at
th
p. Overall, the pa
ta
nt
re
on
r
pa
ap
much powe
e
was immediately
th
t,
ea
d
gr
loa
d
sounde
en with a 4 ohm
of Stroker amps
power on tap, ev
e
of
nt
ou
am
was actually mor
e
le
th
ab
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ail
am
power av
(2 ohms to each
s
em
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sy
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er
am
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tt wo
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than my 1,000 wa
authority provid
s and
um
dr
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vin
kic
Ha
e
e.
lik
at
ts
hi
could toler
awesome. Bass
t
gh
ou
th
I
d
is just so much
ht and hard, an
power available
tympani were tig
g
isp
cr
d
an
d
kick out of havin
more controlle
fun! I get a real
generally a little
ve
I
ha
at
’t
th
p
dn
ta
di
om on
D amplifiers. I
so much headro
than some Class
however,
on
ris
til even I think it’s
pa
un
m
up
co
it
ct
can turn
time to do a dire
al
on
rs
amps just want
as merely a pe
too loud, and the
so I’ll leave that
,
ile
wh
a
you have never
at on them for
to keep going. If
observation. I be
of
er
ifi
pl
am
er
with thousands
t warm, neith
heard a system
and while they go
of
wo
ich
e
th
wh
to
able
ring my testing,
clean watts avail
got hot at all du
e
ar
Th
he
.
to
cy
lf
ien
se
your
the overall effic
ers, you owe it to
speaks again to
was sitting
I
as addicted to
t
bu
be
e,
on
bl
so
di
ll
au
u’
it… Yo
fan was slightly
g
in
th
no
th
wi
from the amp
it as I am.
less than 5 feet
ntrols and
co
e
Th
.
rs
ea
y
m
between it and
test report
Cerwin-Vega Mobile
Stroker S2000.1
MEASURED PERFORMANCE SPECIFICATIONS - amp
Manufacturers
Rated Power
Actual Measured
Power
@ 1.0% THD+N
@ 12.6V Battery
Actual Measured
Power
@ 1.0% THD+N
@ 14.4V Battery
500 x 1 @ 4 Ω
571 x 1 @ 4 Ω
750 x 1 @ 4 Ω
1000 x 1 @ 2 Ω
1013 x 1 @ 2 Ω
1190 x 1 @ 2 Ω
2000 x 1 @ 1 Ω
1662 x 1 @ 1 Ω
2160 x 1 @ 1 Ω
Signal to Noise Ratio referenced to 2V output.
(CEA-2006A) (1 watt @ 4 ohms)
-93.5dBA
Signal to Noise Ratio referenced to full output.
-122.3dBA
0.02%
Distortion at rated power
CEA-2006A rated 4 ohm Power (minimum power per channel
developed over the entire audio bandwidth)
720 watts/ch
Maximum Efficiency at full 2 ohm power per ch.
Maximum Current @ full power 2 ohms per ch.
76%
1.8A
131mV- 6.1V
221A
Frequency Response (-3dB)
21Hz – 190Hz
Idle Current (warm)
Input Sensitivity
High Pass Crossover
n/a
Low Pass Crossover
40Hz – 250Hz
-24dB/oct
Bass EQ boost
Phase Adjustment (degrees of shift @ 100Hz)
PERFORMANCE/BENCH MEASUREMENTS
On the bench, I decided to measure the amps as single units,
simply because that’s how most people will probably use them.
The Stroker amplifier performed as well on the bench as it did in
the listening room, delivering more power than advertised, and in
fact meeting it’s 4 ohm and 2 ohm power ratings even at a battery
voltage of 12.6V. Compared to a conventional Class D amplifier,
the signal to noise ratio was excellent, and the output impedance
was also very low, thanks to no large inductors in the output circuitry. The phase adjustment is advertised to be 180 degrees, and
I measured 180.1 degrees at 100 Hz. The amplifier turned on and
off with no popping from the woofer, and when a dead shorted the
outputs, the protection circuitry activated, and the amp recovered
automatically when the short was removed.
+12dB @ 30-125Hz
180
Conclusion
www.cerwinvegamobile.com
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PERFORMANCE AUTO & SOUND – WWW.PASMAG.COM
I’m a fan of the concept of Class GH amplifiers as subwoofer amps. I
think the sound quality is generally improved, and the efficiency is almost
as good as a Class D amp. I’m also a fan of BIG power on the subs. A
system with scads of headroom on the bottom end is just so much fun to
play with, everybody should experience it. Cerwin-Vega Mobile is back,
and it seems like their reputation for delivering products that play LOUD
is certainly not at risk.