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Page 3: Monobloc Amplifiers at AXPONA 2014

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If for some reason you cannot tolerate more than one channel of sound being amplified within a single chassis, mono amplifiers are just the thing for you. And since there is no shortage of insanity amongst audiophiles, there is a wide variety of mono amplifiers to choose from. Only the truly mad need apply, with bonus crazy points for those like myself who feel a strong, irrational desire for monoblocks exceeding 100 lbs.

AVM MA8.2 
One of the largest and most demanding speakers exhibited at AXPONA, the gigantic German Physiks Emperor IIs, needed a serious amp to drive them with their 300 watt minimum amplification on 4 ohm resistance. The amp chosen was the AVM MA8.2 monoamplifier, which certainly looks brawny enough for the task; within the large aluminum chassis it can muster 1100 watts @ 4 ohms, so the MA8.2s are an excellent match for the aptly named Emperor speakers. The 2 X 1000VA power transformers are mounted in their own shielded case within the amp to prevent electromagnetic interference from affecting any other onboard electronics. The MA8.2 is a bridged design, and twenty 200,000 µF lay capacitors on both sides of the case for the two internal amps. Each amp uses 24 output-FETs are are able to permanently deliver 180 amperes if needed. That is a lot of amp for the money, or to be more specific, $7,800  for the 92 pound unit.

AVM MA8.2

 Atma-Sphere MA-2 mk3.2
The newly improved Atma-Sphere MA-2 mk3-2 monoblock amplifier is an intimidating piece of audio hardware with a price to match at $20,800. This is OTL amplifier, which means it does not use an output transformer, which has the advantage of reduced distortion, as transformers are a major source of distortion. It uses 26 tubes and can output 220 watts at 4, 8, or 16 ohms before clipping. The pair I heard drove some huge electrostatic speakers which filled a large room with ease. Its power consumption versus power output exhibits the typical lower efficiency of class A amplifiers, but the sound itself is first class. If you want to enjoy high quality music playback whilst saving money on heating bills, the MA-2 is a great choice.

Atma-Sphere MA-2 mk3.2

Simaudio MOON 880M Reference Mono Amplifier
Dynaudio’s immense flagship Evidence speakers were being being positively animated with some Daftpunk tracks courtesy of Simaudio’s MOON 880M monoblock amplifiers during my visit. The $21,000/apiece 880M were not out of place with the rest of the high end components used in that system, with respect to price or performance. With a rated power output of 800 watts into 8 ohms and 1600 watts into 4 ohms, there are no speakers that the 880M can’t handle. Among many features this amp has to offer: proprietary Lynx circuitry which is a "no overall feedback" design, a massive oversized power supply, a high damping factor, a capacitor-free signal path, stability with any known speaker impedance, and "Class A" output to 10 watts for great sound quality and good efficiency.

Simaudio MOON 880M Reference Mono Amplifier

Pass Labs XA100.5
Pass Labs’ signature rounded, double-framed meter make their products some of the more stylish high end amplifiers out there. This attractive unit is the XA100.5 monoblock amplifier. It is a class A amplifier that can shift to a class A/B mode when driven past 100 watts. As such, it is only rated for 100 watts at 8 ohms but is capable of much more. Not shown in this picture are some very large heat sinks protruding from the sides, which are needed to keep the amp cool as class A amplification is inefficient and generates a lot of heat. The XA100.5 uses a balanced circuit topology whereby the signal is split in two identical matched circuits. When the signal is summed into opposing phase for the output stage, the noise and distortion which was generated in phase is cancelled out. The end sound, as was heard on the Magico S3 speakers, was outstanding. The XA100.5 monoblocks are priced at $16,500 per pair.

Pass Labs XA100.5

Venture V200 A+
These Venture V200 A+ monoblock amplifiers have a rated output capability of 200 watts, a considerable amount for a pure class A design. Details from the brochure and the web product page are pretty sparse, but they seem to be using some premium parts such as Mundorf capacitors and Jensen 4 pole electrolytic capacitors. A strange aspect of their operation, copied from their product page: “The VP100L preamplifier is able to put the V200A+ in normal or stand-by position with the remote control or manually with the switch, gaining immediate access to its highest level of musicality, with a short warm up time of 15 minutes instead of the usual 4 hours needed to reach operating temperature.” The V200 A+ amplifiers cost a whopping $120,000 per pair.

Venture V200 A+


And, to finish this segment of our coverage, how about a headphone amplifier?

In recent years a growing trend among is audio electronics manufacturers is taking headphone amplifiers seriously instead of slapping in the cheapest possible headphone jack just to tick off a checkbox in a list of perfunctory ‘features’. Nowadays you see a lot more high performance headphone amplifiers installed in A/V receivers, integrated amplifiers, computer audio interfaces, preamplifiers, soundcards, and so on. Nonetheless, one does not achieve the status of “true headphone devotee” unless one uses an outboard headphone amplifier. Here is an example of one of those at AXPONA …

Woo Audio WA22 Headphone Amplifier
This formidable headphone amplifier, the WA22, is a fully tube driven and fully balanced class A design. It can handle a headphone impedance of 8 to 600 ohms, so it will work with any set of cans. It has balanced and unbalanced inputs, and 3 pin, 4 pin, and ¼” headphone outputs. The right knob functions as a high / low impedance switch and also as a power switch. The WA22 base cost is $2,000 and can be ordered with a variety of different tube upgrades. A Sennheiser HD800 was used to demonstrate them, and the resultant sound was terrific with the brief orchestral and rock music samples that I heard.

Woo Audio WA22 Headphone Amplifier


AXPONA Part 2 Coverage Conclusion

Of course, our coverage only touched a few of the many amplifiers, preamplifiers, and DACs which were on display. When money becomes less of a consideration, the systems can become fairly exotic with a mixture of old and new technology, ideas, and aesthetic. There is a near infinite combination of components from which everyone who wants a hi-fi sound system can choose to make the perfect setup for their circumstances. As with so many other hobbies, the extravagance of a sound system is limited only by the extravagance of capital one is willing or able to invest. Stay tuned for next and final segment where we dive into my favorite component: loudspeakers!

 

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Recent Forum Posts:

oppman99 posts on May 31, 2014 15:22
I just don't understand the appeal of vinyl. IMO digital sounded better in every room that had both vinyl and digital sources. I thought the sq was much better at last year's show as well.
shadyJ posts on May 28, 2014 20:44
I think $73k for an amp is dumb. You could take a monster pro-amp like a powersoft digam k10, have it modified, and hire a guy to put it in an ultra fancy custom case for a lot lot lot less than $73k. I still think the Burmester is cool, but it's just a poor value.
haraldo posts on May 28, 2014 16:54
7
shadyJ, post: 1033282
13541
That big shiny thing at the bottom of that stack is the Burmester 909, it's a 600 watt x 2 @ 4 ohms amplifier. It also has a 1,250 watt x 2 @ 1 ohm spec. Burmester claims it is stable for a 1 ohm load. It costs $73,500. It's stupid and I want one.

What's stupid about that?
I'd like to buy a Goldmund amp … that makes the Burmester 909 look like a bargain … but I will never be able to afford it …. not even in my dreams ….
FozzieT posts on May 20, 2014 22:17
So, why the photo of the gorgeous Monitor Audio speakers, but no review? Did they suck?
shadyJ posts on May 19, 2014 23:58
13541.vB
That big shiny thing at the bottom of that stack is the Burmester 909, it's a 600 watt x 2 @ 4 ohms amplifier. It also has a 1,250 watt x 2 @ 1 ohm spec. Burmester claims it is stable for a 1 ohm load. It costs $73,500. It's stupid and I want one.
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