



Background



Usual disclaimer. I’m not an audiophile . I just really like listening to music.





I’ll start by describing my decent into the rabbit hole. While researching headphones in early January 2018 I came across Massdrop.com (If you are easily tempted, stay off the site.). I was leaning toward picking up a set of Sennheiser HD650 and discovered that Massdrop.com had the Massdrop/Sennheiser HD6XX available for $200. The HD6XX are supposed to be clones of the HD650 which were priced at around $375 on Amazon.com. I figured I would save some money and placed an order. I subsequently realized that the order wouldn’t ship until the end of March 2018. OK. I’m an adult. I can wait a few months. Ha!









Why the NX4?

I decided to go with the older version of the NX4 over the updated NX4 DSD for 3 primary reasons:

The NX4 works natively with iOS devices via a lightening to micro USB cable (Don’t lose or break this cable. They are very rare and expensive to replace.). The DSD version does not.; I don’t have any DSD content and even if I did, I seriously doubt I could hear the difference over high bitrate AAC/MP3 or FLAC.; The newer version was $50 more expensive.

Specs and Build I won’t get into all the specs you can read those here: http://www.tpdz.net/en/products/nx4/index.htm . Key features of the NX4 worth mentioning are the Hi/Lo Gain and Bass Boost. It accepts analog line in/out and USB sources and comes with all the cables you should need to connect to different source devices. From a build quality perspective, I have been using the NX4 daily for about 3 weeks with no issues. It’s a solid, well built piece of kit.







Impressions

My reference point for DAC/Amps up until this point was the AudioEngine D1 which I have had for over 5 years. The D1 is a great device that runs off of USB power from a PC or Mac and provides a nice clean signal for my desk speakers and served as my desktop headphone Amp. I was able to drive my newly acquired 400i with the D1 in terms of volume, but I suspected I still might be missing something and also was interested in a more portable solution so that I could listen in other parts of the house. After reading favorable reviews on Amazon I pulled the trigger on the NX4.





I am not going to say the difference between driving the 400i and my other headphones with the NX4 was life changing, but it was definitely noticeable. Compared to the D1 the NX4 brought more depth/warmth to the 400i. Again, I think the D1 is a great device. Definitely a solid DAC. The difference with and without the D1 to my Audyssey LES speakers is night and day and worth it for that even if the headphone amp portion isn’t the best.

The sound quality of the iPad through the 400i is pleasing, but volume is limited. With the NX4 this is no longer the case, it gets plenty loud with the NX4.

The NX4 made the Pixel 2 a great source for music. The Pixel 2 OTG functionality feeds the NX4 a pure signal and let’s the DAC do it’s thing.

The 400i crave power. On high gain setting I can listen comfortably between 12 & 3 on the dial.



The biggest surprise for me with the NX4 was the life it brought to my OG Grado SR80 that I have had for about 10 years and my 5 year old AKG K550 . While these headphones don’t really need amplification to drive them they certainly benefit from it. I have been using the D1 with the headphones for years and thought I was fine. I was wrong.





As with the 400i, the NX4 gave the SR80 more liveliness and depth and also took off some of the treble intensity (sibilance) that often caused the SR80 to be fatiguing to listen to. Dollar for dollar I don’t know if there is a better headphone than the SR80. They sound fantastic with the NX4. If you are a budding audiophile, want to give a gift to a music loving friend and/or need a cheap portable setup you can get an NX4 and SR80e for less than $200. BudgetAudiophile indeed.





As for the K550, they are probably best for studio mixing use as opposed to casual listening. They don’t sound bad, they just don’t sound as good as the 400i or SR80 with or without the NX4 (i know closed-back vs open-back). That said, the NX4 bass boost really helps the K550 with some low end punch. I’m not a bass head, but do appreciate some low end. Both the K550 and SR80 are driven well by the NX4 in low gain between 11 and 1.





Conclusion

While I await the arrival of my Aune X1s, I am glad I picked up the NX4. It gives me a portable option for driving my growing collection of headphones and really enhances my listening experience. It’s well built, easy to use and relatively affordable. For $100 it’s a worthy upgrade for any music lover that uses mobile devices as their primary music player.





Gear Used For This Review

Headphones: Grado SR80 | AKG K550 | Hifiman HE400i

DAC/Amp: AudioEngine D1 | Topping NX4

Players:

MacBook Pro - iTunes | Plex | VLC



iPad 2017 - VLC



Pixel 2 - Plex | VLC

Music Sources: 256 kbps and above AAC and MP3 | FLAC | Google Play Music | Amazon Prime Music

































































