Perhaps Iím being a bit too harsh on the Grace Design m903. After all it sounded better than the formerly C.A.S.H. listed Benchmark DAC1 HDR in a direct comparison. However, when I reviewed the DAC1 HDR in May 2009 and subsequently placed it on the C.A.S.H. List computer audio options were less than endless. 24 bit / 96 kHz playback via USB was wonderful and the DAC1 HDRís adaptive USB transfer mode licensed from CEntrance was one of the best available. Today the DAC1 HDRís USB implementation is a bit long in the tooth. Since May 2009 asynchronous USB transfer mode has become all the rage as has support for sample rates up to 24 bit / 192 kHz and higher. As time passes and competition heats up good component designers are pushing boundaries producing better sounding products with more features. The Grace Design m903 has many more features than the DAC1 HDR and sounds noticeably better in my system. In addition to the very different design of the m903, as compared to the DAC1 HDR, my complete audio system has changed since my DAC1 HDR review. My system is much more resolving and revealing of component differences than at any time in CA history.
Unfortunately better sound than a competing component doesnít equate to a CA recommendation. Thereís a subjective continuum of sound quality from the worst to the best. Near the middle of that continuum rests good components like the Grace m903. Higher up on my sound quality continuum is components like the Bel Canto DAC 1.5 ($1,395), Ayre Acoustics QB-9 ($2,750), and the Berkeley Audio Design Alpha DAC Series 2 ($5,000). Major League Baseball teams donít get to complete against only those teams with the same payroll. Similarly evaluating sound quality should not be done in a vacuum or strictly by price points. With that in mind I donít believe Iím being too harsh on the m903 although I am holding it to a high standard. Compared to many other DACs in all price ranges the m903 is a home run, if not grand slam when it comes to features. In terms of sound quality the m903 is a base hit up the middle. The over all sonic character of the m903 when used with solid state amplification was veiled and unlively with an extremely tight image located too deep into the soundstage for my taste. Switching to a McIntosh MC275 tube amp brought the sound to life and moved the image much closer to my listening position. The major trade-off when using the MC275 in this particular setup was loss of detail for a lush, lively, and sweet midrange. No matter what amplification I used there was a consistent lack of low level detail through the m903. The finer details and nuances of recordings could not be heard unless the volume was louder than my normal listening level. This louder level became fatiguing after about thirty minutes. I had to choose between more detail with sore ears or less detail with comfortable ears.
Comparing the sound quality of the m903 to that of the DAC1 HDR was revealing of differences between the components. The DAC1 HDR sounded more washed out and less punchy when reproducing the electric bass. Comparing the sound quality of the m903 to one of my current references the Berkeley Audio Design Alpha DAC Series 2 revealed sonic shortcomings beyond that of component versus component. After listening through the m903 for weeks playback through the Alpha DAC Series 2 in combination with the Alpha USB left me in awe. Goose bumps, toe tapping, and a little sonic disbelief describe the experience and my thoughts. Air around instruments, transparency, low level detail, and soundstage were all significantly better through the Alpha / Alpha combination. Based on price this sonic difference should be expected. Regardless of price itís always healthy to compare components in for review with components I consider my reference. In this case I was reminded of the gap that exists between high performance components and how high my bar is set when comparing sound quality.
One pertinent comparison that I would have liked to conduct was the m903 against the Bel Canto DAC 1.5. Shortly after my DAC 1.5 review I sent the DAC back to Bel Canto thus eliminating the opportunity to compare the components. Basing my opinion strictly on memory I prefer the sound of the DAC 1.5 in my system by a large margin. I wasnít longing for detail and didnít experience any unlively sound with the DAC 1.5 like I had with the m903.
People should not read too much into my opinion about any of the components mentioned in this review or any review for that matter. My system is unlike any other system just as my ears are unlike any other ears. The biggest "instrument" in all systems is the room. Nobody other than myself listens to music in my listening room. If someone plans on purchasing my house with my current system intact and somehow mirroring my ears then they can take everything I say to heart. Otherwise please be cautious and listen to the Grace Design m903 in your own system concluding anything good or bad.
The Grace Design m903 is truly a feature-fest. This all-in-one DAC / Preamp / Headphone Amp not only looks great and is built like a tank, it offers all the features of todayís best designs. Many of the features such as the publicized asynchronous USB transfer mode and high precision analog volume control, playback and front panel display of frequencies up through 192 kHz, and both balanced and unbalanced in/outputs are somewhat visible to the naked eye. The features that impressed me just as much and demonstrated the high level of expertise Grace Design has in designing components were located behind the scenes in the Setup Menu. The ability to set a default power up level, lock the output toggle switch, independently control the three analog outputs or use exclusive output mode that mutes the unselected output are some of the very nice features not found in most consumer products competing with the m903. Also included in this Setup Menu is the ability to enable display dimming. Once enabled the very bright display will dim after four seconds of inactivity. I consider this a critical consumer feature as I listen in complete darkness frequently. When the display is illuminated Grace has cleverly implemented a tiny decimal point in the lower right corner to indicate the volume is 0.5dB above the displayed whole number. This enables a smaller display to indicate precisely what level within the 95dB range the m903 is current outputting. Embedded into the analog volume control is a three step acceleration curve. This is a great feature that I used several times per day as I frequently adjusted the volume in-between system changes. The volume encoder has 24 positions that result in a change of 12dB in 0.5 dB steps when itís turned one complete revolution at a slow pace. When encoder rotation speed increases the steps increase first to 2.0dB then to 4.0dB. Over the course of a couple decades Iím sure users will save at least five minutes of their time. Joking aside, this is a very convenient feature that I now look for in all similar components.
Interfacing the m903 with a computer music source can be accomplished numerous ways. The m903 supports AES/EBU, S/PDIF electrical (coax) and optical (TosLink), and high speed asynchronous USB using Gordon Rankinís Streamlength async code. Every digital input supports sample rates from 16 bit / 44.1 kHz through 24 bit / 192 kHz. I listened through the AES and S/PDF coaxial inputs fed from an Aurender S10 music server. Running through playlists containing music at all supported sample rates the m903 handled the frequency changes without flinching. Other components Iíve had in my listening room really struggle with sample rate switches depending on the clock implementation. The Aurender S10 front panel display indicates the frequency of the currently playing track. It was comforting to match this frequency with that on the front panel display of the m903. While not a true bit perfect indicator this frequency display would let the listener know if something major like sample rate conversion was taking place. For example connecting the Olive O6HD music server to the Grace m903 via AES illuminates the 96 kHz indicator clearly showing the O6HD resamples all digital output to 96 kHz.
The Aurender S10 music server has certainly changed my listening habits since placing it in my system. I usually gravitate to its wonderful iPad user interface and excellent sound quality. Once I switched to the m903ís asynchronous USB input fed from a C.A.P.S. v2.0 server I never look back. The async USB input on the m903 was no doubt the best sounding input. All music played through the USB interface was more coherent and ultra tight as opposed to the AES and S/PDIF interfaces that had a loose sonic character or a little lack of focus from the midrange down to the lowest frequencies.
In USB 2 mode the Grace m903, and all other high speed USB DACs, requires driver installation because Windows does not yet support Class 2 Audio. Class 2 Audio is what provides support for frequencies higher than 96 kHz. Versions of Mac OS X at or above 10.6.4 do not require any driver installation as they support Class 2 Audio out of the box (or straight from the Internet in the case of Lion). The Thesycon driver used by Grace and a limited number of other async DAC manufacturers is one of the best drivers available. In my experience the Thesycon drivers work 99.9999% of the time. Installation and uninstallation of these drivers has been flawless. The same cannot be said for other Class 2 Audio drivers.
My software player of choice is J River Media Center 17. When supported by the DAC I use JRMCís WASAPI - Event Style output mode. This output mode lets the audio subsystem pull data instead of pushing data to the system and advantageously creates, uses, and destroys all WASAPI interfaces from a single thread. WASAPI - Event Style allows lower latency buffer sizes, and removes an unreliable Microsoft layer that causes the circling buffers to get out of order resulting in stuttering. In laymanís terms WASAPI - Event Style allows for a more direct data path to the driver / USB DAC. The Grace Design m903 supports WASAPI - Event Style perfectly. I tried all reasonable methods to cause playback problems between J River and the m903 but I was unsuccessful. Sample rate changes were immediate and gapless when track-to-track navigation was configured as such. My entire JRMC and m903 user experience was really a joy as evidenced by my affinity for this playback chain over the Aurender S10 / m903 combination.
The back of the m903 has a couple semi-unique in/outputs and two caveats readers should consider. The m903ís physical USB input accepts what is called a Mini-B 5-pin connector. This in itself isnít a big deal. Flanking the USB Mini-B input terminal are two protruding round metal screws that no doubt result in a very strong long lasting design. Caveat one - Unfortunately this may hinder the use of certain USB cables. The m903 ships with the required USB Standard-A to Mini-B cable that works without issue. In advance of receiving the m903 I procured a Wire World Silver Starlight Standard-A to Mini-B USB cable. This cable features larger robust connector "surrounds" that impede the Mini-B termination from entering the Mini-B receptacle as far as the stock USB cable. The difference between the two cablesí penetration into the Mini-B receptacle is so minute I donít know what type of measuring device is necessary to quantify this difference. Fortunately I used the Wire World Starlight USB cable with Mini-B connector of weeks without a single issue. The cable does not come loose or cause any playback anomalies. In fact Iíve likely made a bigger deal of the situation than necessary, but I want to make sure readers are aware of a possible issue that would not come to light without first hand knowledge of the m903 and different USB cables.
The other semi-unique connections on the m903 are balanced TRS analog outputs. These are common in the professional audio world but few and far between on consumer devices. When I talked to Michael Grace, Founder of Grace Design, at the 2010 Audio Engineering Society (AES) convention at San Franciscoís Moscone Center he expressed his engineering preference for TRS connectors over XLR connectors and practically speaking said thereís no room for much larger XLR connectors on the m903. Shortly after this conversation I ordered some TRS to XLR cables and XLR to TRS adapters. I wanted to option to use my existing XLR to XLR cables with adapters and the TRS to XLR cables without adapters. The TRS outputs on the m903 are placed very close to each other due to the space restrictions of its small size. Caveat two - Unfortunately this will prohibit the use of large XLR to TRS adapters. The audiophile in me ordered very nice, expensive, and robust adapters only to find out they were too large to connect both simultaneously. I didnít think about the fact that adapters large enough to accept the XLR connector would be just as large as the XLR inputs Michael Grace omitted from the m903 design partly because of space restrictions. Fortunately the Mogami Gold TRS to XLR cables from Guitar Center of all places worked perfect.
One feature of the Grace design m903 that I did not dedicate much time to is the headphone amplifier. I listened through the m903 with a pair of Senheiser HD600s and Grado RS1s. Neither the most current models nor the most resolving headphones available. the sound quality was very good, but Iím not a regular headphone user with memories of many headphone amps for comparison. Making judgements on the m903 headphone amp quality may be a disservice to Grace and potential customers. Letís face it, thereís no place like Head-Fi for headphone information. Here is a link to Head-Fi user NA Blurís m903 review.
The Grace Design m903 is no doubt a well designed and constructed all-in-one DAC / Preamp / Headphone Amp. I would be remiss not to recommend all interested readers listen to the m903 themselves in their own systems and to read opinions from many other sources. My listening experience with the m903 is but a single data point among many. Grace Design doesnít get such high accolades and industry respect for making lackluster products. These guys are great designers, great people, and offer product support thatís second to none. It just so happens that the m903 didnít gel or have any real synergy with my current audio system. In fact it would be my pleasure to have the m903 back in my listening room in twelve to eighteen months for another go-around. I am 100% sold on the feature set of the m903. I believe this product has set a high standard with features other manufacturers must now consider obligatory not optional.
- Product - Grace Design m903 Reference DAC / Preamp / Headphone Amp
- Price - $1,795
- Product Page - Link
- User Manual - (PDF)
- Brochure - (PDF)
- Setup Quick Reference - (PDF)
- Source: Aurender S10, C.A.P.S. v2.0 Server
- Remote Control Software: Aurender iPad App, Remote, BitRemote
- Remote Control Hardware: iPhone 4, iPad, MacBook Air
- Playback Software OS X Lion 10.7.2: iTunes 10.5 (141), Amarra 2.3, Pure Music 1.82, BitPerfect 0.30
- Playback Software Windows 7: J River Media Center 17
- DAC: Berkeley Audio Design Alpha DAC Series 2, Benchmark DAC1 HDR
- Preamp: Audio Research LS27, TAD Labs C2000
- Amplifier: Bel Canto Design ref1000m, McIntosh Labs MC275
- Loudspeakers: TAD Labs CR1 Compact Reference
- Cables: AudioQuest Redwood Loudspeaker Cable, AudioQuest Niagara Balanced XLR Analog Interconnects, Mogami W3173 Heavy Duty AES 110 ?, AudioQuest NRG-100 Power Cables , Wire World Silver Starlight USB Cable, Kimber Select KS2020 S/PSIF Coax Cable, Mogami Gold Studio 1/4" to XLR Male Analog Interconnect