Mitek Product Development - Amplifiers

1. 1995 1997 1998 1999 1999 2000 2000 2001 2001 2002 2002 2002 2003 2003 2004 2004 2005 2006
MTX MTX MTX MTX MTX Coustic MTX MTX Xtant CousticXtant MTX Xtant MTX CousticMTX MTX MTX
Thunder Blue
Thunder
Thunder Blue
Thunder
Road
Thunder
Thunder Thunder X Series A SeriesRoad
Thunder
Xtant SeriesThunder MXA ThunderThunder
Classic
Xtant1.1i
A3001 RT251d Xtant3.1 600db TA2301 TC3001
PRO250xd Thunder250d Thunder4250d 401db Thunder421d 800db MXA4001 TA3401 TC4001
1 CH TA4501
A6001 Xtant6.1 1200dbMXA6001 TA5601 TC6001
Thunder1500dx PRO500xd Thunder500d Thunder6500d 801db Thunder801d 1600dbMXA8001 TA7801 TC8001
Thunder1000dThunder81000dX1001 Thunder1501d TA81001
TA92001
Thunder240 PRO502
Thunder250
Thunder250x
PRO50x2 RT2120
160se
Thunder102 Thunder4122 161se RT202 Thunder202 400s TA3202 TC2002
Thunder280 PRO752 Thunder275x PRO75x2 RT2200 240se Thunder152 Thunder6152 241se A2002 Xtant2.2Thunder282 600s MXA3002 TA4252 TC3002
2 CH Thunder2160PRO1502Thunder2150x PRO150x2RT2400 Thunder302 Thunder8302 Thunder342 800s MXA4002 TA5302 TC4002
400se 401se TA7402
Thunder502 TA8502
Thunder2300PRO3002Thunder2300x PRO300x2RT2600 600se 601se Thunder942 1200s TA91002
Thunder225HO
3 CH X603
Thunder4160PRO504 Thunder4200x PRO50x4 RT4240 320qe Thunder204 Thunder4244 A4004 RT404 Xtant4.2Thunder404 800q MXA4004 TA3404 TC4004
4 CH Thunder4320PRO754 Thunder4300x PRO75x4 RT4340 480qe Thunder304 Thunder6304 Thunder684 1200q MXA6004 TA5604 TC6004
X604
TA7804
5 CH Thunder5400x PRO400x5 Thunder405 Thunder4405 Thunder895

3. Thunder95 Thunder98 Thunder2000
Thunder2001Thunder2003
Thunder2005
Through hole
Technology
Surface mount
technology with the
PCBA on the bottom
Surface mount technology and bonded
fin forced air cooling. Die cast chassis
and modular assembly.

4. Thunder95
Brand: MTX
Year Released: 1995
Location Produced: Phoenix, Arizona USA
Number of Models: 6 Initial launch of the Thunder amplifier
product line.
•Created the initial Audio
Precision test system.
•Worked as liaison between
engineering and production to
negotiate the optimal test time
to production output.

5. Thunder98
Brand: MTX
Year Released: 1998
Location Produced: Phoenix, Arizona USA
Number of Models: Expanded the Thunder amplifier line
from 6 models to 10. Added a lower priced Thunder250, a
5 channel Thunder5400x, and a Thunder225HO. In 1999
added the Thunder1500dx.
•Led the newly leaderless team
in product development.
•Consolidated mosfets to a total
of 3 types from 9 to leverage
purchasing.
•Changed the fet bars to
accommodate more than 2 fets
for production efficiency.
•Designed the first self
oscillating class d amplifier as
the Thunder1500dx.

6. Thunder2000
Brand: MTX
Year Released: 2000
Location Produced: Phoenix, Arizona USA
Number of Models: Reduced the Thunder amplifier line
from 10 models to 9. Added 2 more class d amplifiers and
removed 3 under performing amplifiers.
•Changed potentiometers to fully enclosed
type for better reliability and lower
production labor cost.
•Changed the remote gain control to THAT
Corp part for better control.
•Changed large capacitors to snap in type
for lower production cost.
•Added a header pcb to the transformers
to lower production cost.
•Created the Thunder1000d using the new
smt line in Phoenix.

7. Thunder2001
Brand: MTX
Year Released: 2000
Location Produced: Phoenix, Arizona USA
& Mumbai, India
Number of Models: Maintained the models to 9.
•Converted the entire Thunder amp
line to smt technology.
•Out sourced the industrial design
and changed the design to have the
PCBA on the bottom.
•Quoted the entry level models in
China, Korea, and India. Launched
production in India at mid life with a
cost reduction of 35%.
•The Thunder81000d became an
industry leader in SPL competitions.

8. Thunder2003
Brand: MTX
Year Released: 2003
Location Produced: Phoenix, Arizona USA
& Mumbai, India
Number of Models: Maintained the models to 9.
•Re-skinned product
from the Thunder2001 to
extend the extremely
successful 2001 line.
•Achieved industry
leading reliability.
•Peak sales of $50
million.

9. Thunder2005
Brand: MTX
Year Released: 2005
Location Produced: Longhua, China
Number of Models: Expanded the Thunder
amplifier line to 16 models to maximize all price
points in the declining market.
•Radical redesign of the thunder
amplifier line to change the
cooling from high mass to
forced air in light of the rising
aluminum costs.
•Created a platform of 4 die cast
tooled sizes and a modular
design to accommodate the
same PCBA for 2 models per
size.
•Launched in the new joint
venture factory in Longhua,
China.

10. Road Thunder

11. RoadThunder99
Brand: MTX
Year Released: 1999
Location Produced: Phoenix, Arizona USA
Number of Models: 6
•Re-skinned select group of
models from the Thunder98
line as entry models.

12. RoadThunder2002
Brand: MTX
Year Released: 2002
Location Produced: Mumbai, India
Number of Models: 3
•Leading product line to
launch in the new Mumbai,
India contract manufacturer.
•Slim line designed to meet the
promotional needs of dealers.
•Utilized a cost down
assembly method to use the
sheet metal as the cover and
the logo.

14. Blue Thunder96
Brand: MTX
Year Released: 1996
Location Produced: Phoenix, Arizona USA
Number of Models: 6
•Re-skinned product from
Thunder95 for exclusive sale
by Circuit City.

15. Blue Thunder99
Brand: MTX
Year Released: 1999
Location Produced: Phoenix, Arizona USA
Number of Models: 10
•CoDeveloped with Phier and
Vimex ultra low torque
trimmers for greater crossover
control.
•Launched the Pro250xd and
Pro500xd self oscillating class
d amplifiers.
•Utilized new Ultra Blue LED to
make the product visible from
the entrance of a Circuit City
store with the product
mounted at the rear of the
store.

17. MXA 2004
Brand: MTX
Year Released: 2004
Location Produced: Mumbai, India
Number of Models: 7
•Re-skinned product from
Thunder98 for exclusive sale
to Circuit City
•Launched the Pro250xd and
Pro500xd self oscillating class
d amplifiers.

18. TC2005
Brand: MTX
Year Released: 2006
Location Produced: Longuha, China
Number of Models: 9
•Re-skinned version of MXA
made in China.

19. LSB1
Brand: MTX
Year Released: 1997
Location Produced: Phoenix, Arizona USA
Number of Models: 1
•First designed product.
•330+ thru hole components in
a high density design.
•Winner of many awards and
coveted by audio
competitors.

21. X-Series2001
Brand: Xtant
Year Released: 2001
Location Produced: Phoenix, Arizona USA
Number of Models: 3
•High end designed Xtant
product line.
•X1001 modeled after the
Thunder81000d.

22. A-Series2002
Brand: Xtant
Year Released: 2002
Location Produced: Phoenix, Arizona USA
Number of Models: 4 models with a cosmetic
change in the the first year.
•Xtant mid line designed with
the reliable Thunder amp
circuitry.
•First die cast heatsink design.

23. Xtant Series
Brand: Xtant
Year Released: 2002
Location Produced: Phoenix, Arizona USA
Number of Models: 4 models with a cosmetic
change in the the first year.
•Xtant mid line designed with
the reliable Thunder amp
circuitry.

24. Military intelligence. Jumbo shrimp. Microsoft works. These are called
oxymorons, words that seem to contradict each other, put together for the
amusement of those who know better. Many audio enthusiasts might even
consider "Audiophile Full-Spectrum Class D" an oxymoron; until now, that is.
The engineering team at Xtant, world famous for doing things differently, has
dared to introduce the first full-range Class D designed for sound quality in
the new Xtant 1.1i Mono Amplifier.
Xtant rates the output power of the 1.1i at 100 watts into 4 ohms and 100
watts into 2 ohms. That's not a typo, and it grabbed my attention, too. Current
limiting to keep the amplifier operating within its optimum range? Perhaps.
Rail switching, like some other Xtant models? Maybe. Xtant also claims a
frequency response of 17Hz to 20kHz, +2dB. Seems a bit ambitious for a
Class D.
Cosmetics As I mentioned, the 1.1i is a 100-watt mono amplifier, so I received
a pair of them for testing. They arrived in boxes seeming to contain more air
than amplifier. Of course you probably think I am kidding, yet at 6.5"L x
5.81"W x 1.63"H (about the size of a 20-disc CD wallet), these amps are
unbelievably small. However small, though, these guys are surprisingly
weighty. Xtant Series 2003
Brand: Xtant
Year Released: 2003
Location Produced: Phoenix, Arizona USA
Number of Models: redesigned from the A-series
with the addition of the xtant1.1i
•Converted the A-Series Xtant
product to an extrusion based
with the annealed stainless
steel cover of the traditional
Xtant product.
•Added the Xtant1.1i as a
mono full range class d
amplifier. This utilized the
Broadley class d patent and
pushed the frequency of
operation to over 1MHz.

25. Military intelligence. Jumbo shrimp. Microsoft works. These are called oxymorons, words that seem to contradict each other, put together for the amusement of those who know better. Many audio enthusiasts might even consider "Audiophile Full-
Spectrum Class D" an oxymoron; until now, that is. The engineering team at Xtant, world famous for doing things differently, has dared to introduce the first full-range Class D designed for sound quality in the new Xtant 1.1i Mono Amplifier.
Xtant rates the output power of the 1.1i at 100 watts into 4 ohms and 100 watts into 2 ohms. That's not a typo, and it grabbed my attention, too. Current limiting to keep the amplifier operating within its optimum range? Perhaps. Rail switching, like some
other Xtant models? Maybe. Xtant also claims a frequency response of 17Hz to 20kHz, +2dB. Seems a bit ambitious for a Class D.
Cosmetics As I mentioned, the 1.1i is a 100-watt mono amplifier, so I received a pair of them for testing. They arrived in boxes seeming to contain more air than amplifier. Of course you probably think I am kidding, yet at 6.5"L x 5.81"W x 1.63"H (about
the size of a 20-disc CD wallet), these amps are unbelievably small. However small, though, these guys are surprisingly weighty.
On one side of the amplifier are three fins, part of the black, extruded aluminum heatsink. Atop the black heatsink is a polished stainless steel cover that immediately proclaims, "I am Xtant!" The power, speaker and input connections are all on one side,
accompanied by the gain control and an electric blue power indicator LED. It is clean, classic and unapologetic in appearance. When you take the cover off to gain access to the mounting screw holes (wrenches and screws provided), the "Black Box"
mystery continues inside, where Xtant purposely removed part number markings on the ICs.
Design and Layout All the connections are on the front of this amplifier and the flow from the power side to the signal side makes good sense. Battery power enters through terminal blocks large enough for 4awg cable on the right-hand side of the panel
and runs straight back to the primary caps (3000uF total) and on to the switching devices mounted to the heatsink. The transformer is a little forward and to the right, while the rectifiers and thermal sensor occupy the center area of the heatsink. Signal
input is front and to the left of center, adjacent to the speaker outputs, which are capable of handling 8-gauge cable. The output FETs are on the left side of the heatsink and feed the output filter directly forward and on to the output terminals.
Xtant uses little standard circuitry in the 1.1i. The input section isolates the ground (or shield) side sufficiently to treat it as the negative side of a balanced line input. The negative side ultimately runs into a differential amplifier (op amp). Even if you don't
have a balanced line source unit there are at least three advantages to using it with standard RCAs. First, the signal clarity and definition is much greater. Second, most of the noise that can be radiated into your signal cables will be eliminated through
common mode rejection. Third, you can connect virtually any head unit directly to the amplifier.
Nearly all of the components are surface mount, even some of the large resistors, lending itself to tighter tolerances. The board itself is double sided, and there are no jumpers or buss bars present. All of the components are on one side of the board,
and everything is tight and neatly laid out. We applaud Xtant for using 105-degree C rated capacitors in both the primary and secondary portions of the power supply rather than the more common 85-degree C caps that, because of heat, degrade
more quickly over time.
The power supply in the Xtant 1.1i is self-oscillating, switching at 1.06MHz. This is one of the keys to the extended frequency range for any class D amplifier. To have a high frequency range the switching frequency must be at least twice the highest
frequency that you want to reproduce. Additionally, you have to have a low-pass filter on the output to get rid of the switching frequency (noise) itself. If you want frequency response out to 20kHz, and the switching frequency is 40kHz, you now have to
come up with a sharp enough filter (crossover if you prefer) to reduce the 40kHz noise sufficiently in a single octave. To have a signal (20kHz) to noise (40kHz) ratio of 100dB, you would need a 100dB/octave low-pass crossover, and it has to be
passive! Obviously this is not going to work at 40kHz, because a practical passive filter will only attenuate 6-, 12-, 18-, or 24dB (that's really pushing it). In fact, we want to use a lower slope if possible to preserve the sound quality. So we need more
octaves, and therefore a higher switching frequency so that we can use a passive output filter to eliminate the noise. As an example: using a 6dB/octave filter, a switching frequency of 1.28MHz would result in a mere 60dB attenuation from a 20kHz
signal.
"But wait," you say, "the 1.1i shows a 105dB signal-to-noise ratio and response out to 34kHz!" They're obviously using a higher slope for their output filter, but, alas, there's more going on here than they want known at this point. (They'd have to kill me if I
told you.)
The output section uses two N-channel Phillips devices rated at 150-watts dissipation each, more than adequate per this amplifier's rating. Looking at the layout, it is notable that this is a true mono amplifier. This is not your typical mono amplifier that
consists of two individual channels that have been bridged internally, but with only a single channel output. And, these amplifiers are designed to be used on your full-range speakers.
Performance The frequency response was an astounding 3Hz to 34kHz at -1dB, better than many class A/B amplifiers and far greater than any class D I've come across. How did Xyant do this? I can see why they painted out the marks on all of the ICs
inside! Power was higher than rated, even at 12.5V, and did in fact increase substantially from 4 ohms to 2 ohms. Apparently the current limiting isn't too restrictive, but seriously, wouldn't you really rather have the extra power? The owner's manual
indicates a regulated power supply, but again it's not very tight as the power definitely increases from 12.5VDC to 14.4VDC.
Very curious was the relationship between the THD and SNR (signal-to-noise ratio). With a THD of 0.7 percent, I would not have expected the SNR to measure much over 85dB, and yet it was actually over 105dB (double checked and verified by
another lab nearby). The Output Power to THD was not the typical gentle rise towards maximum power, then rising sharply as the amplifier begins to clip. Instead it rises to about 75 percent power, then drops off before rising sharply at clipping, never
exceeding 0.7 percent throughout its range.
The thermal protection circuit consists of progressively reducing the power until the amplifier begins cooling down. My tests showed two steps of power reduction and then eventual shutdown under continuous extreme thermal stress. I am a big fan of
the power-reduction format because the music virtually never stops. Chances are very good that in a system your amplifier will recover from heat build-up without you ever noticing the power reduction. And on those long trips nobody wants their music
shutting off!
The over-current protection works in the same manner -- that is, the power is reduced if the amplifier is playing into a lower than allowed impedance or short circuit.
The owner's manual does a great job of taking you step-by step through the installation. The "Connections and Controls" page makes use of small black and white illustrations that are hard to distinguish, but with only four items to contend with you could
always look at the amplifier itself. Xtant offers a four-year materials and workmanship warranty when the unit is installed by an authorized dealer, otherwise it's one year. As always, keep your sales receipt, and Xtant offers on-line registration to keep
things easier if you ever need warranty service.
Listening test The two amplifiers were first installed in my car to power the front separates that utilize prototype passive crossovers. I am happy to announce that there was no noticeable engine noise, so I went straight for the volume knob for some fun.
The big item of concern was the high frequency range, which is the weak link for a Class D. I have to admit to being a little dismayed at finding no issues here, so I moved on to imaging, tonal balance and the like.
After the in-car audition, the Xtant duo was connected to a pair of Clements Audio prototypes in the Redrock theater room. This round was geared for slightly more serious listening. My initial instinct again was to audition the high frequencies. As in the
car, I was met with exceptional performance. One item to note: there is a very slight turn-on pop due to a minute DC offset. However, this pop was detectable only in the Redrock theater room, not in the car.
The following is a cumulation of both in-car and in-theater listening experiences: from my trusty Car Audio Nationals competition CD (from the dawn of car stereo civilization), I listened to Jennifer Warnes' "Bird on a Wire." The vocals, which can sound
thin and out of phase on some systems, sounded full and rich, and the triangle could be heard clearly. The fanfare's dynamic range and the snare hits sounded as real as I've ever heard.
Robben Ford's "Talk To Your Daughter" and "Eyes Of Love" by Michael Ruff have the ability to reveal low frequency equalization or imbalance in an amplifier's performance, but both tracks were pleasantly uncolored when played through the Xtant 1.1is.
Finally, I consider "Tomorrow's Girls" from Donald Fagen's Kamakiriad to contain some of the most well played and recorded cymbal work of all time. Each tap and slip was clearly evident, crisp and smooth in all the right places. When pushed too far,
though, there was a distinct graininess affecting the upper ranges. With a typical class A/B amp you notice a muddiness in the lower mid-range section of this track, revealing that the clipping signature is very different on this amplifier. Military intelligence. Jumbo shrimp. Microsoft works.
These are called oxymorons, words that seem to contradict
each other, put together for the amusement of those who
know better. Many audio enthusiasts might even consider
"Audiophile Full-Spectrum Class D" an oxymoron; until
now, that is. The engineering team at Xtant, world famous for
doing things differently, has dared to introduce the first full-
range Class D designed for sound quality in the new
Xtant 1.1i Mono Amplifier.
Review of the Xtant1.1i

26. Performance The frequency response was an astounding
3Hz to 34kHz at -1dB, better than many class A/B
amplifiers and far greater than any class D I've come
across.Military intelligence. Jumbo shrimp. Microsoft works. These are called oxymorons, words that seem to contradict each other, put together for the amusement of those who know better. Many audio enthusiasts might even consider "Audiophile Full-
Spectrum Class D" an oxymoron; until now, that is. The engineering team at Xtant, world famous for doing things differently, has dared to introduce the first full-range Class D designed for sound quality in the new Xtant 1.1i Mono Amplifier.
Xtant rates the output power of the 1.1i at 100 watts into 4 ohms and 100 watts into 2 ohms. That's not a typo, and it grabbed my attention, too. Current limiting to keep the amplifier operating within its optimum range? Perhaps. Rail switching, like some
other Xtant models? Maybe. Xtant also claims a frequency response of 17Hz to 20kHz, +2dB. Seems a bit ambitious for a Class D.
Cosmetics As I mentioned, the 1.1i is a 100-watt mono amplifier, so I received a pair of them for testing. They arrived in boxes seeming to contain more air than amplifier. Of course you probably think I am kidding, yet at 6.5"L x 5.81"W x 1.63"H (about
the size of a 20-disc CD wallet), these amps are unbelievably small. However small, though, these guys are surprisingly weighty.
On one side of the amplifier are three fins, part of the black, extruded aluminum heatsink. Atop the black heatsink is a polished stainless steel cover that immediately proclaims, "I am Xtant!" The power, speaker and input connections are all on one side,
accompanied by the gain control and an electric blue power indicator LED. It is clean, classic and unapologetic in appearance. When you take the cover off to gain access to the mounting screw holes (wrenches and screws provided), the "Black Box"
mystery continues inside, where Xtant purposely removed part number markings on the ICs.
Design and Layout All the connections are on the front of this amplifier and the flow from the power side to the signal side makes good sense. Battery power enters through terminal blocks large enough for 4awg cable on the right-hand side of the panel
and runs straight back to the primary caps (3000uF total) and on to the switching devices mounted to the heatsink. The transformer is a little forward and to the right, while the rectifiers and thermal sensor occupy the center area of the heatsink. Signal
input is front and to the left of center, adjacent to the speaker outputs, which are capable of handling 8-gauge cable. The output FETs are on the left side of the heatsink and feed the output filter directly forward and on to the output terminals.
Xtant uses little standard circuitry in the 1.1i. The input section isolates the ground (or shield) side sufficiently to treat it as the negative side of a balanced line input. The negative side ultimately runs into a differential amplifier (op amp). Even if you don't
have a balanced line source unit there are at least three advantages to using it with standard RCAs. First, the signal clarity and definition is much greater. Second, most of the noise that can be radiated into your signal cables will be eliminated through
common mode rejection. Third, you can connect virtually any head unit directly to the amplifier.
Nearly all of the components are surface mount, even some of the large resistors, lending itself to tighter tolerances. The board itself is double sided, and there are no jumpers or buss bars present. All of the components are on one side of the board,
and everything is tight and neatly laid out. We applaud Xtant for using 105-degree C rated capacitors in both the primary and secondary portions of the power supply rather than the more common 85-degree C caps that, because of heat, degrade
more quickly over time.
The power supply in the Xtant 1.1i is self-oscillating, switching at 1.06MHz. This is one of the keys to the extended frequency range for any class D amplifier. To have a high frequency range the switching frequency must be at least twice the highest
frequency that you want to reproduce. Additionally, you have to have a low-pass filter on the output to get rid of the switching frequency (noise) itself. If you want frequency response out to 20kHz, and the switching frequency is 40kHz, you now have to
come up with a sharp enough filter (crossover if you prefer) to reduce the 40kHz noise sufficiently in a single octave. To have a signal (20kHz) to noise (40kHz) ratio of 100dB, you would need a 100dB/octave low-pass crossover, and it has to be
passive! Obviously this is not going to work at 40kHz, because a practical passive filter will only attenuate 6-, 12-, 18-, or 24dB (that's really pushing it). In fact, we want to use a lower slope if possible to preserve the sound quality. So we need more
octaves, and therefore a higher switching frequency so that we can use a passive output filter to eliminate the noise. As an example: using a 6dB/octave filter, a switching frequency of 1.28MHz would result in a mere 60dB attenuation from a 20kHz
signal.
"But wait," you say, "the 1.1i shows a 105dB signal-to-noise ratio and response out to 34kHz!" They're obviously using a higher slope for their output filter, but, alas, there's more going on here than they want known at this point. (They'd have to kill me if I
told you.)
The output section uses two N-channel Phillips devices rated at 150-watts dissipation each, more than adequate per this amplifier's rating. Looking at the layout, it is notable that this is a true mono amplifier. This is not your typical mono amplifier that
consists of two individual channels that have been bridged internally, but with only a single channel output. And, these amplifiers are designed to be used on your full-range speakers.
Performance The frequency response was an astounding 3Hz to 34kHz at -1dB, better than many class A/B amplifiers and far greater than any class D I've come across. How did Xyant do this? I can see why they painted out the marks on all of the ICs
inside! Power was higher than rated, even at 12.5V, and did in fact increase substantially from 4 ohms to 2 ohms. Apparently the current limiting isn't too restrictive, but seriously, wouldn't you really rather have the extra power? The owner's manual
indicates a regulated power supply, but again it's not very tight as the power definitely increases from 12.5VDC to 14.4VDC.
Very curious was the relationship between the THD and SNR (signal-to-noise ratio). With a THD of 0.7 percent, I would not have expected the SNR to measure much over 85dB, and yet it was actually over 105dB (double checked and verified by
another lab nearby). The Output Power to THD was not the typical gentle rise towards maximum power, then rising sharply as the amplifier begins to clip. Instead it rises to about 75 percent power, then drops off before rising sharply at clipping, never
exceeding 0.7 percent throughout its range.
The thermal protection circuit consists of progressively reducing the power until the amplifier begins cooling down. My tests showed two steps of power reduction and then eventual shutdown under continuous extreme thermal stress. I am a big fan of
the power-reduction format because the music virtually never stops. Chances are very good that in a system your amplifier will recover from heat build-up without you ever noticing the power reduction. And on those long trips nobody wants their music
shutting off!
The over-current protection works in the same manner -- that is, the power is reduced if the amplifier is playing into a lower than allowed impedance or short circuit.
The owner's manual does a great job of taking you step-by step through the installation. The "Connections and Controls" page makes use of small black and white illustrations that are hard to distinguish, but with only four items to contend with you could
always look at the amplifier itself. Xtant offers a four-year materials and workmanship warranty when the unit is installed by an authorized dealer, otherwise it's one year. As always, keep your sales receipt, and Xtant offers on-line registration to keep
things easier if you ever need warranty service.
Listening test The two amplifiers were first installed in my car to power the front separates that utilize prototype passive crossovers. I am happy to announce that there was no noticeable engine noise, so I went straight for the volume knob for some fun.
The big item of concern was the high frequency range, which is the weak link for a Class D. I have to admit to being a little dismayed at finding no issues here, so I moved on to imaging, tonal balance and the like.
After the in-car audition, the Xtant duo was connected to a pair of Clements Audio prototypes in the Redrock theater room. This round was geared for slightly more serious listening. My initial instinct again was to audition the high frequencies. As in the
car, I was met with exceptional performance. One item to note: there is a very slight turn-on pop due to a minute DC offset. However, this pop was detectable only in the Redrock theater room, not in the car.
The following is a cumulation of both in-car and in-theater listening experiences: from my trusty Car Audio Nationals competition CD (from the dawn of car stereo civilization), I listened to Jennifer Warnes' "Bird on a Wire." The vocals, which can sound
thin and out of phase on some systems, sounded full and rich, and the triangle could be heard clearly. The fanfare's dynamic range and the snare hits sounded as real as I've ever heard.
Robben Ford's "Talk To Your Daughter" and "Eyes Of Love" by Michael Ruff have the ability to reveal low frequency equalization or imbalance in an amplifier's performance, but both tracks were pleasantly uncolored when played through the Xtant 1.1is.
Finally, I consider "Tomorrow's Girls" from Donald Fagen's Kamakiriad to contain some of the most well played and recorded cymbal work of all time. Each tap and slip was clearly evident, crisp and smooth in all the right places. When pushed too far,
though, there was a distinct graininess affecting the upper ranges. With a typical class A/B amp you notice a muddiness in the lower mid-range section of this track, revealing that the clipping signature is very different on this amplifier.
Review of the Xtant1.1i
Even with its diminutive frame, the Xtant1.1i is a mighty
mite with the heart and soul of a giant. Maybe jumbo
shrimp isn't an oxymoron after all.

28. Coustic 2001
Brand: Coustic
Year Released: 2001
Location Produced: China
Number of Models: 4
•China factory designed.
•Oversaw project.

29. Coustic2004
Brand: Coustic
Year Released: 2004
Location Produced: Mumbai, India
Number of Models: 6
•Re-skinned version of
MXA2004 for Coustic