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Equipment Review

April 2004

Flying Mole DAD-M100pro HT Mono Amplifiers

by John Crossett

Click to view measurements of this product



Review Summary
Sound "Detail [is not] thrust in my face, but presented as part of the overall sonic picture"; "deep, wide soundstage" and "plenty of power" too; on the downside are "a slight opacity" and "some hardness and flatness to instruments that play in the upper midrange."
Features "Small and lightweight" digital mono amplifiers with "power output belies their looks: 100W into 8 ohms and 160W into 4"; draw "(a mere 30W each) and run very cool."
Use Speaker binding posts "accept banana plugs or bare wire but have no provision for spades"; can purchase "brackets to mount the amps directly to the back of your speakers" and thereby use short speaker-cable runs.
Value "You’ll likely need to shell out more green for a more refined amplifier…and you probably won't get the power that the DAD-M100pro HTs offer."

You’ve got to have some mighty big ambitions if you want to break into the world of audio and home-theater electronics nowadays. To succeed, you have to create a product that not only offers good performance but real value for the dollar, especially when your company name is Flying Mole and you're headquartered in Japan, where so many audio and home-theater products are made. Flying Mole Corporation's line of DAD-M100pro mono power amps are usable for two-channel audio and home-theater (the DAD-M100pro HT, the version reviewed here), in the car or from DC power (DAD-M100pro CI), and in professional applications (DAD-M100pro BI). Flying Mole has priced the amps at a mere $349 USD each, making them especially intriguing products.

The DAD-M100pro HT amps are not imposing-looking, but their manufacturer-specified power output belies their looks: 100W into 8 ohms and 160W into 4. They're small and lightweight -- 5 3/16"W x 9 5/16"D x 1 11/16"H and under 1 1/2 pounds. Circuit details are sketchy, but what I do know is that the amps use 1-bit digital technology along with what Flying Mole calls Bi-Phase Fusion technology, which involves integration of the power and amplifier sections for improved "conversion efficiency." The DAD-M100pro HTs are class-D digital amplifiers, and, as such, they draw little power compared to traditional power amps (a mere 30W each) and run very cool, which I assume made it possible for the amps to be so compact in size -- no heatsinks required.

On the front of the DAD-M100pro HT you will find an on/off rocker switch, a green LED to indicate that the power is on (there is also an LED on the front of the top panel, directly over the front-panel LED), and a level control, which Flying Mole suggests turning up all the way and not using as a volume control. On the rear panel, the DAD-M100pro HTs are just as simple, with an RCA input, a pair of speaker binding posts and an IEC three-prong power-cord receptacle – that's it. But then, just how much can a designer squeeze into a 5" x 2" area?

A word regarding the binding posts. They are the kind found on many inexpensive receivers -- the kind that accept banana plugs or bare wire but have no provision for spades. They are the only real cost-cutting measure of the DAD-M100pro HT’s design, and one I’d love to see replaced with better-quality five-way binding posts.

One final feature of the DAD-M100pro HT worth mentioning is the option of purchasing brackets to mount the amps directly to the back of your speakers. I can easily see how this might be of benefit in a home-theater setup, making for less cable to route and fewer components for which you need to find room, but it’ll work equally well in an audio-only context, as it would allow for much shorter speaker-cable runs (which are always more expensive than interconnects) from amp to speaker.

Review system

I used the Flying Mole DAD-M100pro HT amps in place of my usual Sunfire Stereo power amp (and briefly a Marantz PM 57 integrated amp) and connected to Magnepan MG1.6/QR speakers via a biwire set of Alpha Core M2 speaker cables (fortunately the speaker cables have banana plugs at both ends). Front-end components are a VPI HW19 Mk IV turntable with modified Rega RB300 tonearm and Clearaudio Aurum Beta S cartridge, and a Marantz 8260 SACD/CD player. The preamp is my reference Audio Research SP16, although I also used the Belles 21A preamp for a short period. I used both Alpha Core TQ2 interconnects as well as a pair of DH Labs BL-1s. All components (except the power amps, which sit on a slab of granite and a homemade sand box on the floor) rest on a Target three-shelf rack.


The first thing about the DAD-M100pro HTs' sound that grabbed my attention was the detail that they presented -- not detail thrust in my face, but presented as part of the overall sonic picture. There it was for me to pick out if and when I chose to. I initially became aware of this trait while listening to an SACD I’ve become very attached to: Harmonia Mundi’s Mozart - Night Music [Harmonia Mundi HMU 807280] as played by the Academy of Ancient Music under the direction of Andrew Maize. This smaller-than-usual orchestra was spread out before me, and I could get some sense of both the recording's venue as well as the individual musicians intermingling with the space around them. If I paid attention, I could hear things such as the musicians shifting in their chairs or turning pages, and the physical sounds of playing their instruments. But all of these details were simply made a part of the overall performance, not detail just for the sake of detail.

Take two

I received the pair of Flying Mole DAD-M100pro HT amps that Bascom King measured, and I used them with my usual lineup of electronics and speakers: Lamm L2 Reference preamp, Wilson Audio WATT/Puppy 7 speakers, Esoteric DV-50 universal A/V player, Zanden Model 5000 Mk III DAC, and Mark Levinson No.37 CD transport. I also had ProAc Response D38 and Thiel CS2.4 speakers on hand, and used them with the Flying Mole amps as well. I mention all of this to give you context for my comments. Other than a Stereovox HDVX coaxial digital cable, the Flying Mole amps were the least expensive part of this system, including the Nordost Valkyrja interconnects and speaker cables I used. On the one hand, such budget-priced amps would rarely be used with such pricey equipment. On the other hand, putting the Flying Mole amps into such a high-falutin' system should convey very well what they sound like. For direct comparison, I also had Odyssey Audio's $750 Khartago stereo amp on hand, and I listened to it before and after my sessions with the Flying Mole amps.

The size and weight of the DAD-M100pro HTs were surprising the first time I encountered the amps at CEDIA 2003 and even more so once I witnessed how powerful these amps are. They drove the speakers with which I used them to very loud levels and without obvious strain, but that power was also a necessary element in achieving the best sound from these amps.  The volume control needs to be goosed or the presentation sounds somewhat closed-in and dynamically stunted. Also, at low and moderate levels a certain diffuseness creeps in -- images lack strong outlines and an obvious sense of solidity.

But even at higher volumes, the DAD-M100pro HT amps exhibit some obvious sonic traits. Their grainless, always-pleasant sound makes for fatigue-free listening. Bass impact certainly belies the physical stature of the amps and is very good overall. However, compared to essentially every amp I've heard (including the very fine but much more expensive Bel Canto digital amps), the DAD-M100pro HTs display a lessening of high-frequency vitality and especially the air around performers that we audiophiles crave. Cymbals and brass are missing some of their steely sheen when reproduced over the DAD-M100pro HT amps, and while this helps bad recordings sound listenable, it also causes really good recordings to lose some of their distinctiveness.

Perhaps the sound of these amps is more suited to a home-theater system -- a Flying Mole Cascade multichannel amp that uses the same 1-bit technology is currently under review at our sister publication, Home Theater & Sound. But for high-end two-channel audio, the ample power, small footprint and low price of Flying Mole's DAD-M100pro HT mono amps don't make up for sound that's friendly but uninviting.

...Marc Mickelson

Another recording that stressed this point yet again was Duke Ellington’s Jazz Party In Stereo [Classic/Columbia CS 8127]. On the opening track, "Malletoba Spank," Ellington uses a number of different percussion instruments in addition to his big band. The Flying Mole amps really let the full and differing aspects of each percussion instrument shine. There was a deep, wide soundstage littered with the various percussionists, with each one easily distinguishable from his fellows both via individual tones as well as location.

Those recordings brought another aspect of the DAD-M100pro HTs to the forefront -- their way with the soundstage. I’ve rarely heard a better defined sense of space, both width and depth, laid out in my listening room. Aaron Copland’s "Appalachian Spring Suite," from the new Telarc SACD Rainbow Body [Telarc SACD-60596] was highlighted by the Flying Mole’s way with the recording's venue. The Atlanta Symphony was there in my listening room (or even better, I was transported to Atlanta), each separate section of the orchestra a distinct entity made up of individual players, yet they were all still a part of a greater whole.

Percussion instruments are well served by the DAD-M100pro HT amps. In addition to the Ellington recording noted above, the cymbal work on the Steve Davis Project’s SACD Quality of Silence [DMP SACD-04] was engaging in its realism. I could almost see, in my mind's eye, just where Davis’s sticks were hitting the cymbals. This was the sort of realistic presentation that I’m used to hearing from my Sunfire amp. And the drums themselves were just as well defined. The skin of each individual drum in Davis’s kit was easy to identify, as was how loose or tight the skin was stretched over the body of the drum.

There was plenty of power from the DAD-M100pro HTs, enough to drive my relatively insensitive Magnepan speakers to levels over and above those which I consider normal for listening. I was impressed by this, as I’ve heard costlier amplifiers that were unable to handle this aspect of musical reproduction correctly.

However, the Flying Mole amps have some sonic imperfections -- although their price goes a ways toward making these quibbles instead of full-blown defects. Amidst all of the positive aspects, there’s a slight opacity to the overall sound that tended to remind me, at times rather forcefully, that I was not listening to a highly refined design. Also, I noted some hardness and flatness to instruments that play in the upper midrange. This was especially apparent with the Duke Ellington Jazz Party In Stereo LP, but it was not a matter with just this one recording. These two things diminished my involvement in the music, even as they made the amps inoffensive to listen to.

In comparison

Is it fair to compare a pair of $349 mono amps to a stereo amp that costs over three times as much? This is the case when comparing the Flying Mole amps to my reference Sunfire Stereo, which cost $2295 when still available. The Flying Mole amps’ presentation of detail and their way with soundstage boundaries was enjoyable. My Sunfire amp, however, comes very close in these respects, but it adds more of a sense of the recording's space and a fuller, more 3-D sense of richness to each instrument or singer. It offers a more convincing overall presentation.

I also substituted the DAD-M100pro HT amps for a Marantz PM 57 integrated amp that I use in my two-channel video setup. Here, the Flying Mole amps excelled. Their unforced detail and vast soundstage added excitement to movie and TV viewing. I can understand how using the DAD-M100pro HT amps in a full-blown audio/video system could offer much enjoyment at a relatively modest cost.

Wrapping up

OK, so maybe Flying Mole is an unusual name, and the DAD-M100pro HT amps are tiny, lightweight digital designs. Further, they aren’t the perfect amplifying devices -- they certainly have a sound of their own, one that's always pleasant, especially in terms of presentation of detail and soundstaging. You’ll likely need to shell out more green for a more refined amplifier -- the law of diminishing returns kicks in big-time here -- and you probably won't get the power output that the DAD-M100pro HTs offer. And if size really matters to you, these amps have no peers.

Flying Mole is on the precipice of good things with the unique DAD-M100pro HT digital amps. It will be interesting to see where the company flies to from here.

...John Crossett

Flying Mole DAD-M100pro HT Mono Amplifiers
$349 USD each.
Warranty: One year parts and labor.

Flying Mole Corporation
Waji-cho 5199-1, Hamamatsu-shi
Shizuoka-ken, 431-1115 Japan
Phone: 053-486-6030
Fax: 053-486-6033

Website: www.flyingmole.co.jp
E-mail: info@flyingmole.co.jp

Flying Mole responds:

We appreciate the attention and professionalism you have shown the Flying Mole DAD-M100pro HT amplifiers. There are a few points that we need to make to help put the review in a different context for your readers. First, much of what you describe about the DAD-M100pro HT applies, but some of it no longer does due to a circuit change. Flying Mole engineers increased the input impedance of the amp from 10,000 ohms to 100,000 ohms. This seemingly mundane change dramatically increased the amp's image focus without detracting from the amp's other strengths. Only but a few sample amps have the old circuit design, so all new amps sold in the US have the improved circuitry and sonics.

However, there is another issue worth discussing; we think you may have fallen into a trap common with lower-priced components -- the amps were treated as low-priced components. Right out of the box, we are confident that these amps will treat a listener to better sound than they ever had a right to expect out of $350. But for the DAD-M100pro HTs to really shine, they need to be treated like the high-performance amps that they are. For example, they need a full two months of break-in for peak performance. With their exceptional resolution, they GREATLY benefit from aftermarket power cords, cones, damping/weights and especially power conditioning. In fact, it is power conditioning that dramatically ameliorates one of the review's criticisms -- i.e., the "slight opacity." For readers who want to squeeze even more performance out of the amps, Underwood HiFi (www.underwoodhifi.com) will be offering factory-authorized upgrades, including, among other things, audiophile-approved binding posts.

The DAD-M100pro HTs were designed and voiced with inspiration from the classic triode tube/horn loudspeaker sound that is so popular in the Japanese audiophile community. Flying Mole's engineers focused on achieving the portrayal of detail in a natural, unforced manner and on re-creating the exquisite tonal complexity and harmonic textures found in a live performance. We feel we have achieved these goals, and have nicknamed the DAD-M100pro HT the "Organic Digital Amp" because of the uncanny sense of "organic" realism it conveys. While in stock form it may not be the end-all in transparency, the question becomes, "Would you rather have a transparent window to the recording, or re-create a live performance, albeit in a smoky room?" We believe that the ability to get the latter along with 100Wpc -- for even multiples of $350 -- is chance many music lovers will happily jump at.

Thanks again for your attention and professionalism. We hope that readers will stay tuned for follow-up reviews that comment on changes brought by the new circuit design as well as to explore the other sonic traits of these extraordinary amps.

Flying Mole Corporation

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