May 1, 2009

Genesis Reference GR180 Stereo Amplifier


I would love to love a digital amp. I owned a Bel Canto eVo4 Gen II for a year or so, was hugely impressed the first time I heard a NuForce amp (and reviewed one for Ultra Audio), and at hi-fi stores and trade shows have made a point of listening to as many digital amps as I can.

But even after living with them for a time, I haven’t found a digital amplifier that I loved. That’s not because I haven’t wanted to love them, because they do some things very, very well. Precise bass, for instance, that’s still powerful enough to rattle everything in the house. And speed -- they’re definitely the fastest amps I’ve ever heard. Plus clarity and transparency, as if there’s just nothing between me and the sound. At their best, the class-D amps I’ve heard have approached "awesome," and for technology that’s been popular for scarcely more than a decade, that’s impressive.

What has kept my relationship with class-D more respectful than adoring has been some of the "little" things that audiophiles like to fret about, such as microdynamics and the accuracy of acoustic timbres. In some cases, the sums of these flaws have resulted in the offending gear failing to convince me that a live person was on the other end of the recording -- which is no little thing at all.

So it’s fair to say that, despite my wishing them the best and hoping they’d knock my socks off, I’ve been frustrated by the unrealized potential of the class-D amps I’ve listened to -- at least until the last few months, when the Genesis Reference GR180 stereo amplifier ($4850 USD) has been part of my system.

The re-genesis of Genesis

Imagine, if you will, wanting to buy a pair of really good loudspeakers that you’ve dreamed of owning for years. Finally, you get it together to make the order -- and you find that the company building them is going out of business. But wait -- for not much more than what you were willing to pay for those speakers, you can now actually buy the company! But wait again -- do you really want to own an audio company?

Suffice to say, Gary Leonard Koh answered "yes" to enough questions to end up owning Genesis Advanced Technologies. The decision to use the resources of a loudspeaker company to create an amplifier was equally indirect. To design his speakers, Koh needed a reference amp that had maximum transparency and fidelity to the source material. Partly because of what happens when you’re connecting and disconnecting a loudspeaker circuit dozens of times a day, the amp also needed to be stable during short-term short circuits. So he built such an amp. A dealer happened to hear it, wanted to know when he could start carrying it in his showroom, and the Reference GR360 and GR180 power amplifiers were born.

Before all that, however, there was a lot of testing and listening. The ears that are among the primary test instruments at Genesis are, you might say, all in the family. "I can hear everything that goes wrong with a sound," said Koh. "When I was growing up, I was the kid yelling for the piano tuner before anyone else was bothered by the piano being out of tune." His sister, Carolyn Koh, COO of Genesis, is the other primary listener during product development. "She has perfect pitch and sings in a choir," he noted. "As for me, I listen to live music as often as I can. I listen to everything, and I’ve learned that one of the hardest things for audio gear to handle well is big-band swing with its bass, strings, voices, dynamics, and pace."

In the development of the Reference amps, Koh wanted to accurately re-create those qualities. "I also wanted the amp as transparent as possible while still sounding like live instruments," he said. "What you hear from the amp should be what’s on the recording." That includes the ambience of the recording venue. "Music is the reproduction of the event where the musicians are performing," he said. "You can best re-create the ambience of the performance space when the left and right channels are perfectly in phase and when the two channels are very balanced in output." He also noted that lower frequencies play a larger role in accurately portraying larger spaces than is usually acknowledged. "That fact made it important for me to make sure the Reference amps can re-create sound down to 10Hz."

After surveying all the class-D amps now being made, Koh found that Hypex modules were the best at conveying the sonic qualities he wanted, as well as the most electrically rugged and stable for his purposes. He also found that the power supply used with the Hypex modules made a big difference in the sound, which led to the development of a separate standard power supply, as well as the Maximum Dynamic Headroom Reservoir, or MDHR ($3850).

"What I found during testing was that the smaller the power supply, the more sensitive the amp could be to microdynamic changes," said Koh. "Bigger power supplies could supply greater macrodynamics, but tended to be slower, muscle-bound hunks." His solution was to create a "relay-team power supply" that would remain sensitive while providing substantial amounts of immediate power when needed. Some of the relays are in the standard power supply, some in the MDHR. The additional capacity of the MDHR adds to the Reference GR180’s ability to deal with high-current transients.

Another area Koh paid considerable attention to was vibration control. The GR180 is mounted on Genesis’s Acoustic Suspension System -- a one-inch-thick slab of acrylic with an adjustable, pointed metal leveling screw at each corner -- which helps isolate the amplifier from vibrations in the surface it sits on. Furthermore, the chassis itself is internally damped. "I found back when I was building tube amps that when I hung the circuitry, it sounded better," he said. He uses neoprene and other materials to suspend the components and control microvibrations from the electronics.

Koh’s performance goals for the Reference GR180 -- natural sound, great microdynamics and macrodynamics, impressive bass -- were the goals that I have for my own audio system. I was eager to hear how fully he’d achieved them.

Setup and system

In the first round, I listened to the Reference GR180 by itself. After a number of weeks, the MDHR arrived, and I spent another couple of weeks listening to the system with the new power source in place.

The Reference GR180 bolted easily to the acrylic acoustic-suspension platform. However, the platform itself is pretty large (19.5"W x 15"D), and the points of the four adjustable leveling screws are 18.5" and 14" apart. So if the shelves on your audio rack are 19"W, you have 1/4" on each side. The amp was comfortable enough, though, on my shelf, which measures 24"W x 16"D. The standard power supply, a solid black hunk, comfortably sat in the middle of another shelf on the rack, connected to the GR180 via a Neutrik connector.

The MDHR is designed to mount conveniently atop the GR180, so no extra rack space was required for it. The total height of the acrylic platform, GR180, and MDHR is less than 8.5" -- no taller than a largish analog amp -- so the entire assembly should fit easily into the height of most standard shelves. The MDHR gets its power from the standard power supply, and has its own short Neutrik-terminated cable connecting with the GR180.

As I usually do, I used my own ESP Essence Reference power cables to better compare the device under test and my reference system. The other gear used in this review included an Esoteric X-03SE SACD/CD player, a Cary 306-200 CD player, a Rega P3-24 turntable with Clearaudio Maestro Wood cartridge, a Lehmann Audio Black Cube SE phono preamp, a Classé Audio CP-700 preamp, a Conrad-Johnson Premier 350 amplifier, Classé CA-M400 monoblock amplifiers, Triangle Stratos Australe speakers, Legenburg Apollo speaker cables and Hermes interconnects, a PS Audio Power Plant Premier power regenerator, a Shunyata Research Hydra Model-4 power conditioner, and Stillpoints isolation devices.

I gave the Genesis GR180 a week or so of constant operation to settle in, then started serious listening.


Ever since I heard The World’s Best Audio System 2009 in the North Carolina home of Ultra Audio editor Jeff Fritz, transparency has moved far up the list of the qualities I desire in an audio system. The Genesis Reference GR180 had this quality in abundance -- as much as I’ve heard from any component in my system, including Parasound’s wonderfully transparent JC 2 preamplifier, which I listened to last year. What was best about the GR180’s transparency was that it wasn’t achieved at the cost of distorting the natural timbres of acoustic instruments. I’ve heard any number of systems that sound transparent because they seem to surgically remove all flesh from the bones of the instrumental sounds, but that most definitely was not what the GR180 was doing.

In fact, with the exception of my current reference Classé MA-400 monoblocks ($11,000/pair), the excellent Belles MB-01 monoblocks ($14,000/pair), and David Berning’s Quadrature Z monoblocks ($30,000/pair), I’ve never heard more natural instrumental sounds from an amplifier in my system -- and certainly never from one that cost less than $5000. For example, the GR180 could dive deep into the tonalities of string harmonics nearly as accurately as the Classé amps; it required several brief A/B comparisons before I could clearly hear the difference in tonality between them. But absent this sort of side-by-side comparison, it’s hard to imagine such small differences mattering much. Hands down, the GR180 was the best-sounding digital amplifier I’ve heard.

The level of detail was also remarkable. I was frequently hearing new things in familiar recordings, and different instruments were distinguished as well as I’ve ever heard them. For example, at the beginning of the second movement of the Tchaikovsky Violin Concerto, with Maxim Vengerov accompanied by Claudio Abbado and the Berlin Philharmonic (CD, Teldec 90881), there are several instruments playing together that alternately become more prominent in carrying the musical theme. Through the GR180, these instruments were easily distinguished from the rest of the orchestra, and there was also a realistic texture to the sound. Similarly, there was remarkable sensitivity to this recording’s microdynamics. Vengerov’s vibrato was as easy to hear, and in several sections I was surprised to hear slight changes in dynamics that I hadn’t before.

I’m used to class-D amps doing impressive bass, and the Reference GR180 was no exception. It presented clean, strong, impactful bass that came very close to my memory of the NuForce 9 V2 (still the bass champ of the amps I’ve heard in my system). A range of bass-heavy tunes from Loreena McKennitt, Erin McKeown, and Patricia Barber were joys to listen to, with the deeper string instruments and percussion coming through powerfully and cleanly.

After a few days of serious listening, when the urge to tweak had become irresistible, I found a simple way to improve the GR180’s performance. Given the attention Gary Koh had paid to controlling internal vibrations, I thought it might be worth trying other ways to do it. Sure enough, using Stillpoints footers under the acrylic platform instead of its own leveling screws moved the GR180 another step forward in the re-creation of natural acoustic timbres. Using aftermarket footers also made it less important that the leveling points were so far apart -- the footers could be placed farther in from the edges of the shelf. I also found the Stillpoints footers helpful under the power supply.

On the downside, the GR180 was perhaps not quite as clean and smooth as my reference amps, and seemed slightly constrained when faced with louder dynamic transients and slam. This may partly reflect the fact that the Classé amps generate 400W each, and the GR180 only 180Wpc.

But this is where the Maximum Dynamic Headroom Reservoir leveled the playing field. With the MDHR in the system, the sound was tighter and quicker. Interestingly, louder transients not only got there faster and came across louder, but stayed longer, with better sustained slam. I also found that using the MDHR resulted in the system being even more quiet and smooth, with a small improvement in timbral accuracy. For me, the MDHR added a final 10% to the quality of the sound, and got it very close to that of my reference amplifiers -- and, for that matter, impressively close to the very best amplifiers I’ve heard.

Considerations and conclusion

The Genesis Reference GR180 is the best-performing digital amplifier I’ve heard, and the best amp of any kind that I’ve heard for less than $5000. Adding the MDHR for an additional $3850 makes it even more of a force to be reckoned with, but then, at a total of $8700, it’s up against stiffer competition. Because most of my listening was done and conclusions were drawn without having the MDHR as part of the system, I find the Reference GR180 easy to recommend even without the MDHR. What is clearly a good investment would be to purchase some quality footers to go with the amp and the power supply, which I found made a positive and significant improvement in its performance.

I have to indulge here in a brief fantasy about what might very well be The World’s Most Transparent Audio System Under $20,000. It wasn’t long after I began listening to the GR180 that I found myself wishing I still had on hand the Reference 3A Grand Veena loudspeakers ($7995/pair) and the Parasound JC 2 preamplifier ($4000), so that I could hear them all together as a system. Each represents a high level of affordable excellence in its own category, and all are among the most transparent-sounding components I’ve heard. If any of those manufacturers or an audio dealer wants to assemble such a system at a trade show, please let me know.

As for how much I came to enjoy the Reference GR180, I think the "L" word finally applies. I loved this amp. I felt good when I listened to it. I wanted to hang out with it as long as I could, and I know I could easily live with and enjoy this amp for a long time. The classical music I mostly listen to came across extremely well through the GR180, and the fun stuff -- jazz and world music -- sounded as good as it ever has.

I’m delighted to say that, for my taste in music, class-D has finally arrived. Gary Koh has created something special with the Genesis Reference GR180, and the sound quality it conveys is simply outstanding for its price. Kudos to you, Mr. Koh!

. . . Albert Bellg

Genesis Reference GR180 Stereo Amplifier
Price: $4850 USD.
Genesis Maximum Dynamic Headroom Reservoir
Price: $3850 USD.

Warranty (both): Five years parts and labor.
Genesis Advanced Technologies
654 South Lucile Street
Seattle, WA 98108
Phone: (206) 762-8383
Fax: (206) 762-8389


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