Miniwatt n4 USB DAC/Headphone Amplifier
I was approached by MiniWatt to review their current USB DAC/AMP combo, the n4. I had not really heard much about this company before but they have had several previous products that were well received, including a very compact vacuum tube headphone amp. I hadn't reviewed an "inexpensive" product ($349 MSRP in this case) here on InnerFidelity for a while, so I decided to give it a try.
The n4 USB 2.0 is billed as an "async mode audio interface" which will handle high-resolution audio files up to 32bit/192kHz based on the PCM1795 DAC chip. It is USB-powered from PC/Mac, meaning no external power supply is required, which is nice.
The headphone amplifier is based around the LM4562 op-amp as analogue filter and driver; the power from the Headphone Output is a fairly modest 100mW at 32 Ohm, which will require the use of fairly efficient headphones. I used primarily my excellent PSB M4U2 headphones for this review, as they were both the best electrical match and also the best "real-world" match in terms of what someone might normally pair with a product like the n4. I used the M4U2 primarily in their passive modeno processing.
Physically the very compact n4 is nice looking for a fairly small device. The 1/8" headphone jack is on the front, with a (digital) volume control also on the front. Around back there is a USB in, and analog RCA line level audio outs, as well as a coaxial digital out which means the n4 can be used to convert from USB to Coaxial Digital.
I have to say, I really dislike having to manually download and install drivers for devices in Windows...and the n4 required this. I don't know why it won't work with plug and play, but it SHOULD. This basic fact means there is going to be a class of user that will have trouble getting the n4 to work, and this will give MiniWatt support issues. To make matters worse, the MiniWatt site driver download doesn't have very good bandwidth, at least to the US, and the download of the 27MB driver was VERY slow, almost to the point of being non-functional. It took several attempts to stop and restart the download to get it (this was for SURE not an issue on my endI have a very high bandwidth internet connection and was having no issues at the time of the attempt).
Further complicating this was that the installer package triggered my Virus Protection Software which believed the installer method to be dangerous. This is really poor execution, and I almost gave up. A device in this day and age absolutely cannot require external drivers which then use set-up programs without a digital signature such that any reasonable virus protection software will try to block it. MiniWatt needs to go back to the drawing board and fix its Windows Installation. Supposedly this is not an issue with MacOS, but I did not try that.
On the more positive side, the manual is VERY good, and it was quite clear what needed to be done to get the driver installed and get the device working. Once I got past this obstacle, things were much smoother.
Playing the 24/192 version of Pat Benatar's outstanding debut album "In the Heat of the Night" (from HDTracks.com), the sound was dynamic, smooth, and even, with very nice detail from such a relatively inexpensive AMP/DAC. I compared the playback from the MiniWatt versus a 48/16 downsampled version played back directly from my iPad's headphone out on the PSB M4U2 headphones, and the MiniWatt was clearly bettermore nuanced and cleaner sounding. The title track of this album, which is incredibly well recorded, sounded truly excellent. Pat's voice was exactly as it should beat times beautiful, at times gruff.
I was able to hear subtle details in several tracks from the 24/96 version of Steven Wilson's "The Raven that Refused to Sing (and Other Stories)". This superlatively recorded work is great for testing systems, as it features wide dynamic range and highly varied music. The MiniWatt reproduced "Raven" very well and in an enjoyable way. I have heard the dynamics rendered more explosively, and I have heard details presented more cleanly, but by more expensive products. For a product in its price class and type, I thought the n4 acquitted itself well with "Raven", which is a mandatory listen for me on an audio product these days!
My reference computer playback system is a Pioneer Elite N-50 Network Music Player, which has a very high quality DAC capable of up to 32bit/384kHz(!) playback. It's excellent sounding, and is an absolute steal at $650 given everything that it doesalmost universal format support, USB, coaxial, and optical inputs, Ethernet connectivity, analog and digital outputs, a nice iOS controller appit's an excellent product. It does not have a headphone jack, though, so I have to use it with an external headphone amp, and it's also not portable at all. It's a full sized component. But it serves as my benchmark for PC audio playback, and does so at an affordable price.
The Pioneer is better sounding than the MiniWatt, no doubt about it. As mentioned it's a different breed of cat, and has a different price point (although not radically), but the N-50 is a better sounding source component than the n4. Nonetheless, when I switched between 16/44.1 and 24/96 playback of the same file on the MiniWatt I WAS able to tell the differencethe 24/96 playback was notably smoother. The n4 sounded excellent with hi-bit-rate filessmooth, clear, clean, and neutral. In fact neutral was a very good description of the sound. There were no obvious colorations or "flavorings" that I could detect. I did think that the very low bass had a little less weight than I am used to, compared to the Pioneer, and the sound was slightly less transparent than with the Pioneer. The upper treble was also a bit less delicate, even with 24/96 material.
That said, for the price, and given that it runs directly off USB power and is quite small and light, making it transportable, I thought the n4 did in fact sound very good. And after the initial installation, it performed very well. In actual use, the front panel volume control, which has the same exact function as moving the PC's volume control, was quite handy.
The MiniWatt n4 accomplished one critical feat on a very regular basis, which is that I often forgot I was listening to it. I regularly was drawn into the music and stopped thinking about how it sounded. That's the best thing an audio product can do, what it generally means is that the sound quality is natural enough that nothing is bugging me about what I am hearing. The n4 does indeed accomplish this not so easy trick.
Perhaps importantly to some, 192kbps MP3 files also sounded fairly good. I almost never listen to lossy-compressed music, but I do have some music downloaded in that format and via the MiniWatt those tracks were enjoyable enough for what they were. They definitely sounded better than they did directly from the PC soundcard or from my iPad.
The MiniWatt n4 is a bit tough to give an unqualified recommendation to because of the difficulties I experienced setting it up initially. I believe users want products that work with PCs without needing external driver support, and if god forbid they do need to install external drivers, the set-up of those drivers needs to not make their anti-virus think they are being hacked. This just isn't acceptable, in my opinion.
That major reservation aside, the sound quality of the n4 is very good. But the world is absolutely jammed with USB DAC/Headphone amp options, and it's a tough, competitive segment of the market. The power output of the headphone amp is also not that high, and the potential choice of headphones will be a bit limited, although probably not too limited within the context of what a prospective buyer of the n4 would be likely to use. On the plus side, it can be used as just a DAC, running into another amp, or as a USB > Coaxial converter (although there are less expensive ways to do that). I noticed that MiniWatt has been running a sale on its website offering the n4 at $199it's a much easier recommendation at that price than at the list price of $349. I'm not sure how long that sale will run, but in this hotly contested arena, the n4 is likely to have more success at the sale price.