Pros: Price, features, design, energetic sound
Cons: Aggressive, harsh, but tameable via resampling
Introducing the new Mini-I and Mini-I Pro:
Let's start off with the name. Upon opening the first Mini-I box, I was surprised by its' size. While it is a small device, it is really not very 'mini'ature. At nearly 8 inches wide, 6 ½ inches deep and nearly 2 inches tall, it's more than a handful. I don't begrudge it's size, however, as the feature list more than makes up for it. Looking inside I see the power supply takes up a full third of the interior. Matrix didn't sacrifice power quality for unit size like others do. No wall-warts or small and cheap transformers here.
Looking elsewhere inside I see the Texas Instruments TPA6120 headphone amplifier on the right side of the PCB. Towards the center are either the tandem of Analog Devices AD1955 DACs or the single Sabre ESS9016 as well as the XMOS USB processor. You can also see the back panel is jammed full of inputs and outputs. With the features available and the focus on clean power, it is as small as it can be. I started inside to justify the size being larger than expected, now let's tour the outside.
The face of the Mini-I is very simple and a little boring, but it is still appealing in a minimalistic fashion. One unfortunate decision here by Matrix was using a silver bezel on both the black and silver models. On the black model, the body is black, but the face is still the same as the silver model. I hope they reconsider this decision. As it is, anyone setting this device in a rack will see a silver face plate regardless of color chosen. The body of the device is typically less important, so it's odd that this would be the part that changes color. Under the plate is a translucent black plastic sheet that covers the information display and holds both the ¼ TRS headphone port on the left and the digital volume potentiometer on the right. The volume knob is easy to turn with good feedback to know when you've moved a step.
The side panels are where the screws are located that hold the shell to the unit. They are otherwise featureless except for the voltage selection switch. Matrix seems to be shipping all Mini-Is with voltage set to 230V, so be sure to change it to 115V before you power up if you live where this is the standard power. If you don't, nothing will be damaged, but the unit will not turn on, and it will appear dead. Switch to the 115V setting and it will turn on normally.
On the business end of the device there are balanced XLR and unbalanced RCA outputs on the left, AES/EBU, coaxial, optical and USB inputs in the middle, and the power switch and power inlet on the right. So yes, the Mini-I is one of the cheaper balanced DACs on the market. The fact that it features four input types as well in a package this small and inexpensive is impressive. It's hardly surprising, however, as this is the nature of all Matrix products; sized to the task, quality execution, and affordability.
The OLED screen is well lit, but not obnoxiously bright. Text is clear and easy to read. The active output and inputs are highlighted white. The sample rate indicator changes as playback format is changed. This DAC does click lightly as the clocks change. I don't even notice it anymore.
Build quality is excellent, better than the new M-Stage, but not as good as the insane X-Sabre. The unit has some heft to it, so it might be too much for a transportable rig. It's about the size of a bible and weighs like two of them. It is small and light enough to easily maneuver into and out of your audio rack, though.
Features and operation:
Here's where things diverge slightly. The Mini-I normal with the pair of AD1955s is able to play PCM only, but it does support up to 24bit 384kHz sample rate, including DXD (24/352.8). The Mini-I Pro with it's ESS9016, supports those same rates as well as DSD64 and DSD128. Headphone output impedance is 12 ohms, so depending on your headphone of choice there could be some slight frequency response alteration. Most full size headphones, especially highly resistant types (300+ ohms) will be largely unaffected. See the product page for a complete list of specifications.
The Mini-I Pro also comes with a small metal remote control. This remote may be sold separately for Mini-I normal owners. The remote has 5 buttons including volume up and down, standby toggle, source select and mute. The buttons themselves are a little loose and rattle a bit, but they don't seem fragile or in any risk of falling out. Response by the main unit is instant. Both normal and Pro units can also be controlled by an Apple remote via a menu I will go into next.
Operation of the unit is easy as well as elegant. Since we're dealing with a digital volume solution, the potentiometer is merely a digital wheel that serves as the source selection switch by quickly pressing straight into it, a standby switch by pressing for a full second, and also the navigator of the settings menu. To enter the settings menu, first, with the power switch turned off, press and hold the volume knob in and flip the power switch, then release the knob. Inside the menu vertical scrolling is managed by turning the knob. Selection between options is done by pressing the knob until the desired option is highlighted. This solution is much preferred over buttons littering the facia.
The settings menu is different for the Mini-I and Pro units. This is because the Pro features PCM filter settings (fast and slow) as well as DSD filter settings (50kHz, 60kHz or 70kHz). The other settings are the same. One of the more delightful discoveries about this unit is the pre-amp setting. Set to PRE1, the unit leaves both headphone and line-out (both XLR and RCA) active. PRE2 mutes the output that is inactive, such as plugging in a headphone mutes the line-out. DAC turns the unit into a DAC-only device and disables the headphone output entirely. Most devices either leave both hot all the time or mute when a headphone is inserted, but not both as well as disable the headphone output. Even better is that the Mini-I remembers the volume for the muted output so you can freely swap between headphone and line out without changing the volume every time. This is really handy if you are using the line-out for preamping a speaker rig which will no doubt be a different output level than your headphones.
The sleep on/off setting activates an auto-standby mode when the unit has not had an incoming signal for 5 minutes. This only is effective if the unit has no signal lock and the USB is not plugged in. If you are using a computer source and turn it off, the Mini-I will turn off 5 minutes later. It will not sleep if you are simply not playing sound for 5 minutes. This sleep mode is not like a computer, so it will not wake on playing a sound. To recover from sleep mode, simply press the volume knob for 1 second to reboot.
Remote setting cycles between RM1 (Matrix remote), MC377 (Apple remote), and off, disabling all remote function. Pressing the volume knob with Exit selected will save the settings and reboot the device.
The digital volume is handled well above the musical information for normal listening volumes. If you have it set to a very quiet setting, you may notice slight degradation on your highest resolution files.
The Matrix units I have on hand to compare are from different price points and will be judged accordingly. The X-Sabre at $1100 was love at first listen for me, and the M-Stage at $280 (amp only version) is a budget warrior that will be hard to beat. The X-Sabre features the top Sabre chip, the ESS9018, one of the most expensive DAC chips on the market, and the most finicky for DAC programmers. The ESS9016 in the Mini-I Pro is a scaled back version but supports all of the same features. The AD1955s in the Mini-I normal are slightly dated, but the spec sheet does say they support DSD64. The M-Stage is a purpose built amplifier that shares a similar chassis volume as the Mini-I but in a different shape. I prefer the LT1364 opamp in my M-Stage to go with HD800s instead of the default OPA2134. It will be a tall order for the TI amplifier in the Mini-I to overcome.
1) Mini-I normal alone
2) Mini-I Pro alone
3) Mini-I normal → M-Stage
4) Mini-I Pro → M-Stage
5) X-Sabre → M-Stage
The TI amplifier in the Mini-I units is functional and does genuinely sound good, better than I expected, but it is no match for the M-Stage with the HD800s. There is a little etch in the treble, dynamic contrast is narrower, as is soundstage. It is a neutral amp, though, which is nice. It's not just a throwaway amp which can often be bright or dark, but rarely neutral. The amp seems to be taxed by the job of controlling the HD800s large drivers. Detail is smoothed too much and texture suffers as a result.
Given the poor results with the HD800, I added my Ultimate Ears Reference Monitors (UERM) and Sennheiser HD600 to the mix. Here I found I actually prefer the Mini-I units to the M-Stage. Most of the same issues crop up as with the HD800, but some of these attributes suited the other two headphones. In fact, I've 'lost' many nights the past month by starting a song with my UERMs in one of the Mini-I units then realizing 6 hours had passed and I'd enjoyed every second of it. I also highly enjoyed the HD600 with the Mini-I Pro unit. The DAC's nature strengthened some of the HD600s weaknesses and I feel there is a strong synergy between the two devices similar to the M-Stage and HD800.
The amp test turned out to be headphone specific, not what I expected. The good news here is that the amplifier in the Mini-I should be more friendly to a wider array of headphones than the M-Stage, especially the more affordable headphones that are more likely to be paired with this budget DAC/amp.
Moving on to DAC performance, I first had a myriad of settings to test. I started with the DSD filter settings on the Mini-I Pro. With all of my headphones I preferred the 50kHz setting. The 60k and 70k spread the soundstage too far and it felt like my head was being dipped in the music, an uncomfortable position for sure. I briefly tested my speaker setup that is not all that well adjusted and found I preferred the 60k setting. With that out of the way, I had to determine if I preferred resampling over native on all 3 DACs. I used JRiver Media Center 19 (MC19) to resample on the fly. In the end I preferred the Mini-I in native mode, the Mini-I Pro in DSD128 50kHz mode, and the X-Sabre in native mode.
The Mini-I has a clean, liquid type sound, but lacks sparkle and dynamic contrast. Detail isn't smeared, but it is reduced somewhat. It is a relaxing sound that will provide hours of quality sound if critical listening isn't the goal. This would be an ideal unit for a workplace desk or a bedside nightstand, where enjoyable tunes are wanted, but scalpel-like levels of detail that would distract are not. I don't recommend resampling with the Mini-I as it turns muddier the higher you go, though native high resolution files sound fine.
The Mini-I Pro is a boisterous sounding DAC. The Pro has excellent dynamic contrast and sounds just slightly warm giving great body to instruments and vocals alike. It's aggressive, so it's fantastic for genres like metal, EDM, hard rock, and the sort, but still mellow enough to do a great job with folk and classical. The main problem I have with the Pro is that it has some harshness in the treble. When mixed with it's aggressive tendencies, it can be a bit much, however I found a solution via resampling. Normally resampling waters down the signal losing detail, aggression, and dynamic contrast among other things. The beauty is that the Pro has most of this in spades, so using high level resampling brings this harshness down considerably, while still retaining a well balanced aggressive (but not as much as before) sound that is better than native.
At first listen I didn't particularly like either of the Mini-I units' DACs. The Mini-I was too timid and smooth, but there are uses for this type of sound. The Pro was too aggressive and harsh, but really fun! Resampling the Pro brought it up a notch that surprised me. When resampling with the Pro, this is a formidable DAC at it's price point.
So it's time to see how the newcomers compare to the big man on the Matrix campus, the X-Sabre. The X-Sabre is hard for me to describe because I love it so much, so bear with me. The X-Sabre is both more detailed than both Mini-I units by a great deal, yet at the same time is relaxed and smooth. Immediately noticeable is the level of refinement having jumped up from the Mini-I units. There is more separation, bigger better layered soundstage. After listening to the Pro for some time, the X-Sabre sounds slightly cold in comparison, but that fades quickly as you return to neutrality. There is no question the X-Sabre is on another level of performance. Matrix spent a great deal of time fine tuning the X-Sabre and it shows. Time for a similarly well done balanced amp! Come on!
Looking at the big picture:
Coming up short to the X-Sabre wasn't a surprise, given the price points we're dealing with here. The amp weakness with the HD800 was countered by being excellent with the HD600 and UERM, and likely more versatile with it's intended pairings. Adding up all the small things like balanced output, remote control included (or available), clean and responsive UI, fantastic pre-amp functionality, simple but effective controls and a relatively small size and you have a total package that is hard to beat. Considering the prices, the Mini-I sells for $379, the Pro, $519 (inc remote), these units are great value and certainly worth adding to your wish list.
Matrix continues to bring low price, high performance products to market. I think the M-Stage in particular is one of the highest value items in this market, and the Mini-I units are not far behind. Their performance exceeds their price easily. A great combination to try is a Sennheiser HD600 and Mini-I Pro. I hadn't heard my HD600 sound that good in a long time. With used prices on HD600s typically half of their retail, you can pick up a Mini-I Pro and HD600 at less than $800 for a very compact, high quality rig.