Headphone Sessions 7/6/2011: Grace Design m903 Headphone Amp

July 11, 2011

Grace Design has been well known for their extremely transparent microphone preamps for years. They’ve also maintained a good level of transparency in their previous headphone amp/DAC models, so, when they introduced the m903 we decided to give it a critical listen and see how it stacked up against our beloved HeadRoom Ultra Desktop Amp/DAC. For our tests we used a 2011 MacBook Pro as our source, fed each DAC with an optical signal via an optical splitter and, with no crossfeed on either amp, listened with one of three sets of headphones; Denon D2000, Sennheiser HD800, or Sennheiser HD650. One thing became immediately apparent: we love the way our HeadRoom gear sounds, and we are extremely used to the way our gear sounds! It didn’t matter what headphones we picked up, we were able to blindly pick out the Ultra Desktop quite easily. It’s pretty amazing considering the differences are very subtle nuances, and to some of our less seasoned listeners they did sound identical.

Sound Comparison

The general consensus of the biased and ever-so-faithful HeadRoom crew was that the Ultra Desktop has a slightly warmer, smoother presentation that, all in all, is more listenable than the Grace m903, which sounded more forward in the high and upper-high frequencies, which to some listeners made it the more detailed amp, while to others it was harsh and bright. We did find the m903 to be slightly more open and airy, with slightly better musical separation, however, the Ultra Desktop is far from lacking in depth and spaciousness. We all found the bass extension in both units to be equally far reaching and authoritative, with the Ultra Desktop being a little meatier and slightly less surgically precise than the Grace.


While the Ultra Desktop was voted to have the more “listenable” presentation, it was designed with home or office desktop listening in mind where a person is more likely to lean back in their chair and relax rather than try to pick apart a mix. The Ultra Desktop provides 24/192K capability via the Toslink (optical) and Coax connections and offers upsampling to 16/192K via USB. It also provides two analog RCA inputs and a switchable, volume controlled analog RCA output for desktop speakers or powered monitors. The Ultra Desktop seems to be more capable of driving higher impedance headphones with ease versus the m903, but it’s stated in the m903 manual that it was designed with lower impedance headphones in mind. The Grace Design m903 follows more in the footsteps of Grace’s microphone preamps and is geared more toward the “pro” side of audio with its balanced and unbalanced input and output options, 24/96K driverless USB function and 24/192K USB with driver install. The volume of both line outputs, as well as the headphone output, can be controlled individually to easily A/B test between two sets of stereo monitors and headphones. The transparent presentation puts the m903 right at home in any professional recording studio. [caption id="attachment_2150" align="aligncenter" width="540" caption="Grace Design m903 Back"]Grace Design m903 Back[/caption]

One thing to note is both amps have crossfeed that can be turned on or off. In the m902, the bass response seemed to get quite thin when turning on the crossfeed. Grace Design made necessary adjustments to the effect that the m903 maintains a full bass response when crossfeed is engaged. The HeadRoom crossfeed has the opposite effect, seemingly boosting the bass presence and increasing warmth, hence the adjustable brightness filter on the Ultra Desktop to compensate for this effect.

In conclusion, we find both amp/DAC combos are great values and have their specific place, whether on a mixing desk in a studio or on your desk in the office. For more information on the Grace Design m903 visit GraceDesign.com, or Headphone.com, where you’ll also find everything you want to know about the Ultra Desktop Amp. As always, we headphone geeks are standing by to answer any headphone related questions you have, so give us a call at 800-828-8184.

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