Disclaimer: Grace and Mass Drop supplied the m9xx for the purposes of this review. I didn’t even pay import duties. The m9xx goes for 499$ USD. You can find out all about it here: Grace Design x Massdrop m9XX DAC/amp.
The Grace Design m9xx is a simple, elegant device. From setting volume to cycling through source and various DAC settings, its top knob does everything. And, aside from its cheap rubber pimple feet, it is a solid and well made device. Its top plate is 5mm thick. Folding into and under it is its base, on which lie m9XX’s guts. All port niches are hollowed out of the thick one. The RCAs don’t budge at all. The optical port is perfectly flush; and the USB and mains ports sit in deep, firmly anchored wells. Four bolts, one in each corner, hold it all together.
It is a handsome, understated design, some of whose stylistic cues have been inherited from Grace’s full-size m9xx series. Of those cues, my favourites are the dual headphone out ports, whose classy grey aluminium turtlenecks come directly from the m920 monitoring system.
The two-digit alpha-numeric display is head and shoulders above Chord Mojo’s confusing alien eyes. But, since it displays everything the m9XX can do, at times, it can feel cramped.
What really tickles my fancy is the m9XX’s power supply: low-power over 0,5A USB, suitable for notebooks and computers with half-spec USB ports; and high-power fed via a proper 5V 2A USB connection. No fiddling with awkward adapters. If you’ve got an Apple 5V adapter, you should be good to go. Just pack the m9XX in your suitcase and pack the usual iDevice suspects: lightning cable, mains-to-infinity cable, a USB-lightning converter and favourite short micro USB cable. Oh, and your headphones. Grace have made a brilliant use of commonly available parts.
A long press of the attenuator knob draws up or shuts down the DAC menu. Certain options: low to high power mode switching, for instance, are automatic. It’s an elegant system. Plug in a dedicated power supply to the m9xx’s 5V 2A input and the m9XX switches to high power. Otherwise, it defaults to low power.
After drawing up the DAC option you want, a single click will cycle through options for that item, while a twist of the attenuator will draw up other top-level DAC options.
Cheat Sheet: full stops after an item (dd VS d.d. for instance) mean that option is engaged. My favourite functions are: crossfeed, and display dimmer. The latter dims the display after a few seconds, making the m9XX fairly comfortable for dark rooms and bedside rigs. The former makes comfortable a number of albums.
I also reckon that people will get excited by the DAC’s digital filters: sharp roll off, linear phase; slow roll off, linear phase; sharp roll off, minimum phase; and slow roll off, minimum phase. Each one is well implemented.
Because the display stops at two digits, sussing certain sampling rates is somewhat difficult. 44,48, 88, and 96 are self-explanatory. 176 becomes 17, 192 becomes 19, 354 becomes 35, and 384 becomes 38. DSD64 becomes d1 and DSD128 becomes d2. Whatever you think, this system is far easier to eyeball than Mojo’s alien gaze.
The knob bumps softly every five degrees or so around what amounts to a volume half-stop. Since the volume scale goes from 0 to 99., it means that m9XX has a 200-step volume control. But, rather than opting for a somewhat inscrutable 0-200 scale, Grace added a full stop behind each number. 0 means off. 0. means 0,5. Brilliantly humane.
Finally, I should add that if you’ve got a battery pack that outputs 5V/2A, you can get the m9XX running from any old smartphone.
Performance, sound, and meh (get it?), after the jump: