How a pair of the $25,000 XLH M-2000
Self-Analyzing Balanced Mono Power Amplifier
brings out a self-analyzing Ed Momkus

October, 2006

This is a review of the XLH M-2000 Self-Analyzing monoblock amplifiers. Most audio reviews start with a description of the physical appearance of the product. I generally skim over those parts of the review, except where they provide information about features and number of inputs and outputs. As a result, I’m going to change things around and leave the description for last. The M-2000’s matching preamplifier, the XLH SL-11 XS Balanced Dual Mono Preamplifier is also in for review and will be addressed in a separate review.


 

ESSENTIALS TO KNOW FIRST

My principal speakers are B&W Nautilus 800Ds. There are many highly-admired speakers that I haven’t auditioned, but I love the 800Ds especially for the kind of music I listen to (which is heavily rock, followed by blues and jazz, and a little smattering of classical). However, they need power to really shine. More specifically, they need current. The higher the current delivery, the better the sound. This means that the 800Ds are good speakers with which to test power amps. On paper, the XLH M-2000 definitely seems to fit the bill: It puts out 600/1200/2400 watts RMS into 8/4/2 Ω!  

I like to test amplifiers without a preamp by running my Teac D-70 DAC’s analog output directly into the amp’s input, using EVS Ultimate Nude Attennuators (UNA’s) to control volume. An amp’s input impedance and input sensitivity are important factors in whether it will work well in this setup. Again, on paper, the XLH M-2000 would seem to fit the bill, with an input sensitivity of 1.0V and an input impedance of 10kΩ, although this latter figure seemed a bit borderline – on paper.


 

COMPARISONS AND CONCLUSIONS BEFORE THE DETAILS

How would you like to check out some amps that are 1) very dynamic, 2) very transparent, 3) very uncolored, 4) have a very wide soundstage, 5) have a deep and layered soundstage, 6) have a very low noise floor, and 7) have (as a practical matter) unlimited power capability? Sounds interesting you say? Well….read on….

I won’t keep you in suspense. The M-2000’s just about made me jump out of my seat when I first got them going. Well, maybe that’s a slight exaggeration – my Electrocompaniet Nemo monos are not exactly dainty amps, and I have had a lot of first-hand experience with some muscle amps. However, the M-2000’s character is definitely dynamic, with superb bass. It is in this regard very convincing. It makes you feel the music the way it hits you when you listen to it live in a good listening venue. It is also very quiet, both subjectively and according to its published specs. It creates a layered sound stage that is very good. Finally, it can handle delicate music as good as the best lower-power “nimble” amps. In short, it is a very excellent amplifier that is top notch by any measure.

As is the case with all world-class amplifiers, the sound/character/presentation of the XLH M-2000s is what is of real interest. All of the best amps have specifications and abilities which, in “objective” terms are impossible to fault. It is usually more useful to compare them to each other to ascertain the sound they will tend to produce in any particular system. Consequently, I’m going to compare the M-2000s with a few other amplifiers which I have heard extensively in my own system. (WARNING/DISCLAIMER: these amps are all big, heavy and draw a lot of juice from the wall. A direct A-B is just not possible in my setup – I would need to duplicate power and cabling, and that’s not in the cards. I have had to rely on sonic memory after wrestling the amps around the room.)

Most of the time I will compare the XLH M-2000’s to three other amps: the dual-mono Mark Levinson 336, the Classe CA-M400 monos and the Electrocompaniet Nemo monos. I will also make a few comparisons to the VTL MB-450 Signature monoblocks, though these will by necessity reach back into old sonic memory.

We all know that it’s hard to get overall dynamics right if the bass isn’t up to par. To start with, the M-2000 produces very clean dynamics, particularly dynamic chest-thumping bass. That’s not to say that it does so indiscriminately, as not all bass is meant to be “chest-thumping”. However, not many amps can realistically reproduce the ultra-low vibrating bass of organ solos, the rumbling electric bass that shows up on Sting’s "Brand New Day", the tight and fast electric bass played by Jaco Pastorius and the acoustic sounds of an acoustic double bass played in a jazz club. The M-2000 does this with ease, with all components of large-scale dynamics - including attack and decay – clearly audible. In fact, if I were to look for a nit to pick, I’d say it’s almost too real. By that I mean you can hear every note – even those that are tough to hear live in an intimate musical venue. By comparison, the Electrocompaniet Nemos, which produce a somewhat richer overall sound, reproduce very low bass with slightly less distinctiveness (however, this could in part be the result of the power cords – see below). By further comparison, the Mark Levinson 336, which is not as rich as the Nemos, just doesn’t have the power to drive the B&W 800D’s lowest bass with the authority of the M-2000 or the Nemos. Finally, the Classe CA-M400s are tighter and more detailed than the other three, but not as tonally rich.

Second, the XLH M-2000 produces a multi-layered soundstage that is very transparent. In doing this it is slightly more forward than either the Nemos or the Levinson 336. I normally prefer a slightly laid-back or neutral presentation, but the slightly forward nature of the XLH M-2000’s is more than offset for me by the depth it adds to the presentation. It’s as though the instruments located at the back of the stage remain there, but the instruments that are closer to the edge of the stage come forward. I suspect that this could be especially beneficial in a room where the speakers can be placed eight or more feet from the wall (mine are out about 5 feet from the wall and can’t really go further given my room configuration). The Classe has nearly as good depth, but produces a more ephemeral sound than the M-400s. By that I mean that the Classe’s soundstage is “airier” than the other three, which impart more solidity to the images. Only the VTL MB-450’s produced a better soundstage depth, while maintaining a solidity and richness to the music. However, it didn’t have the bass punch of its solid state competitors (although it was still quite good in that respect).

Third, all of the amps referred to here have very low noise floors, and I had a very hard time subjectively distinguishing one as being better than the others. However, all were superb in this respect, and you would really have to look at the specs to choose one over the other in this criteria.

Finally, for sheer raw power, the XLH M-2000 and the Nemos clearly surpassed the others. This is only to be expected based on their power specifications. However, the M-2000’s (I suspect that because of the Nemo’s richer texture) were the more dynamic of the two. However, it is at this point that I have to interject more physical details about the M-2000 and my setup.


 

TIME TO ADD SOME DETAILS

I didn’t want to put you off by starting with these facts. First, the XLH M-2000s are 176.37 pounds each. You heard me right. That’s 352.74 total pounds of amplifier. (Remember when I said that these types of amps are hard to A-B easily?) I received, unpacked and set them up all by myself, but I recommend that you get a buddy to help. Second, like the old Levinson 336, the M-2000 comes with its own dedicated power cord, so you will need to tweak some other part of your system to adjust its sound. This may put some of you off, but don’t let it. If you are looking for a top-notch high power amp, make sure you check these out. Third, the power cord plug is a 20-amp plug, which means that one of the two blades is perpendicular to the other (not parallel, as with 15 amp plugs). If you don’t have the right type of outlet, you’ll either need an adaptor, or you’ll need to change the wall plate. It’s also possible that the M-2000 may trip your breaker when you turn it on, which may signal the need for upgraded electrical. This did not happen to me, but I do have two 20 amp circuits that are dedicated to my monoblocks. However, I can tell you that if you are looking to buy high power amps of this caliber you should use 20 amp circuits. (See below for information about my present system to get a handle on system influences.)

The only one of these things that affected the review was the dedicated cord. I have been able to change the sound of various amplifiers by changing out the power cord, and it would have been interesting to hear the comparison with the XLH M-2000 using the same cord. It may be that a richer-sounding cord (like my Zcable Cyclones) would have made the two amps sound more similar. This is not meant in any way to imply a defect in the sound of the M-2000. It is clearly how the designer intended to voice the M-2000. My comment is merely a reflection of today’s high-end audio trends, which have moved toward giving the user the ability to tweak the sound of an individual component by changing out its power cord.

The power cord also has some effect on the price comparison. The $25,000 XLH M-2000’s are more expensive than the Nemos, but once you add the Zcable Cyclone PCs to the Nemos, the price differential goes away.

Despite these hardships, you will be rewarded when the M-2000 has been warmed up and is cranking out the Who’s “Tommy”, Eleanore McAvoy’s “Yola” or Perez Prado’s “Best of Mambo”. The dynamic presentation of the M-2000 is clearly evident in these and all other recordings. Remember, I am running this system without a preamp. When I actually added the XLH SL11XS Balanced Dual Mono preamp into the system, I actually thought I detected heart palpitations. However, that’s a story for the next edition of Dagogo.


 

CONCLUSION

I have been on a roll now for several reviews. I have received a series of expensive world-class products in a row and have had a very hard time finding fault with them. (Why do I feel like I have to find a fault?) (Ok, my fault. –Ed)




SYSTEM. So that you can get a handle on system influences, here’s my current system, which has been
tweaked to be an all-solid state/digital system that leans toward the “tube sound”. My front end is powered
via a dedicated electrical circuit. A Silent Source Signature PC runs from the wall outlet to a Walker
Velocitor S, and two additional Silent


Source Signature PCs run from the Velocitor to an Esoteric P-70 and D-70 transport/DAC combo. I run
Silent Source Silver Signature balanced IC’s from the output of the D-70 into a pair of UNAs, which in turn
plug directly into my Electrocompaniet Nemo monoblocks. I control the general volume range by manually
adjusting the UNAs, and I make fine volume adjustments from my listening position by remotely adjusting
the digital volume control on the D-70, rarely attenuating more than 3dB. The DAC has a very good digital
volume control, and I really can’t hear any degradation of resolution unless I’m at very low volumes.
However, using the D-70’s output control in conjunction with the UNAs means that I make only small
adjustments to the output of the DAC and never risk degrading the performance of the P-70/D-70. The
Nemos are connected to B&W Nautilus 800Ds via Transparent Ultra MM Bicable. Each Nemo is powered
by its own dedicated 20 amp electrical circuit, which feeds power to the Nemo via a Zcable Cyclone. All
power outlets are presently Wattgate 381 Gold (though I am about to change them out to compare to the
Walker Audio High Conductivity outlets).

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