Periodic Audio Nickel: Simplicity


Today we’re checking out the Nickel [Ni], a tiny portable amplifier from Period Audio.

Periodic Audio was founded in 2016 by a small group of audio enthusiasts/specialists with over 140 years of combined experience in the industry. Their aim? To provide accessible, high performance audio products that focus on portability, sound, and comfort, not glitz and glamour.

While it isn’t much of a looker, the Ni is packed with tech resulting in a very compact, powerful amp that can easily travel with you during the day. While it is light on features, those that are included make it a very convenient product to use along with your other every day carries.

Let’s dive in and take a closer look.


Thanks to Dan with Periodic Audio for asking if I would be interested in checking out the Nickel. It looked like an interesting product from the product information that has been released at the time, so I accepted and a sample was sent for review. The thoughts within this review are my subjective opinions based on around a month of use. They do not represent Periodic Audio or any other entity. At the time of writing the Nickel retailed for 299.00 USD. You can check it out here on their site:

**Note that this is a b-stock unit. It functions fine but has physical blemishes. Expect a-stock units to be cleaner than the one shown here.**

What I’m looking for:

When it comes to portable amps and DAPs I take a pretty casual approach. If you’re looking for an in-depth look at this thing with measurement graphs going over THD, sinewaves, etc. you’ll want to look elsewhere. All I really care about is how easy is it to use? Is it well built and will it be durable long term? How’s the driving power and overall sound quality? Are the batteries going to run dry part way through a listening session? Is this the kind of device I’m going to take with me everywhere, or it is better suited to listening in the privacy of my home?



Full specifications and measurements can be found on the product page (link in ‘Disclaimer’). I recommend visiting it if you like graphs.

Packaging and Accessories:

The Ni arrives in some neat environmentally friendly, cardboard packaging. On the front is a wireframe-style image of the Ni and the components that make it up. In the top right is the Periodic Audio logo, and the bottom left the Ni log as seen on a periodic table of the elements. Opening the top flap reveals a couple graphs, one for THD and the other showing the gain, along with a list of specifications and some product information. Around the sides of the package are black and white macro images of on of their earphones as well as some additional branding. The back contains more information about the Nickel.

Opening the side flap which requires quite a bit of force thanks to the strong double-sided tape, there is a second cardboard box that is free of any branded or logos. Inside is the Ni tucked tightly into a cardboard cutout. The only included accessories, a 3.5mm aux cable and microUSB cable, are lightly draped into a second cutout. In all you get:

  • Nickel amplifier
  • 3.5mm aux cable
  • microUSB cable

Overall a solid unboxing experience. I appreciate that they included measurements with clear axis labels and none of the stylized flourishes you usually see when they are included on packaging. Periodic Audio provides a lot of useful information about features and components too, versus the marketing fluff that is more common in the industry. It would have been nice to receive some additional accessories given the price, such as a carrying case for the amp and cables. Maybe a few different aux cables of varying lengths or with jacks of varied styles (ex. 90 degree, 45 degree, and straight) to ensure you get something that is ideal for your portable setup. Other amps include rubber bands to strap the device to your source. Some of those sized to fit the Ni would have been sweet since none of my existing bands fit. Or maybe some Velcro tabs instead. Anything extra would have been nice and helped make this package a better value.

Build and Components:

The Ni has a rugged, polycarbonate shell. The only flourishes breaking up what is otherwise a matte black brick are the white painted Periodic Audio logo and arrows above the input/output jacks. When I took mine out of the packaging, there was a a dusting of what looked to be dried glue or paint smattering the top. While it was easily wiped off with a damp finger, I also saw prominent seams between the two main component parts that made up the shell, along with globs of white glue poking out between those seems. I’ll be honest, it looks more like a prototype than a finished product, though being a b-stock unit I was expecting it to be less that perfect. That said, even were this not a b-stock unit the Ni visually is not particularly impressive. It’s too simple in design for that. It does feel extremely tough though with no flex or give anywhere when squeezing it. Can’t say the same for the metal bodied Xduoo Nano D3 I reviewed a while back. Fit around the important parts, namely the 3.5mm in and outputs, the LED light, and the microUSB slot in the back, is tight leaving no room for play. These somewhat delicate components are well protected.

When it comes to components, that is where the Ni’s seemingly high price tag comes in. Periodic Audio clearly put a lot of thought into what was going to go into the Ni. First off, it uses a brand new Texas Instruments INA1620 chip. This chip can output 140 mA, continuous per channel, and carries along the Ni’s theme of being tiny and portable. This chip is apparently so small they were able to cram it and some other bits and bobbles into the space between the input and output ports. Powering the amp and the amp alone is another piece of Texas Instruments tech, the TPS65133 power controller which results in a low noise floor. A 16F1503 microcontroller from Microchip controls everything including the smart charging setup and LED indicators. TRRS jacks are used which is a breath of fresh air. Why? If using the Ni connected to a phone which seems to be what Periodic Audio is intending, you can plug in a set of headphones or earphones with an inline mic and media controller and not lose that functionality. I personally don’t know of another amp that permits this. What else did they cram into this thing? How about a short depth microUSB connector that allows you to use any microUSB cable with it should you break or lose the included cable, or maybe you just want to use a longer one. Since this little device is going to be in close proximity to other electronics, they also added class IV ESD protection that can handle a 32kV surge. Unnecessary, and I love it. RF protection is in place too, enough to address 10 times the legal RF noise limit at 1cm.

The lithium polymer battery isn’t huge at 280mAh but provides a good amount of play time with the Ni; 8-10 hours. More impressive is the charge time of between 20 to 30 minutes via USB. I see 20 to 30 because their product page says 30 yet the packaging says 20. Either way, it is not marketing fluff and it really does charge that quickly. From the USB 3.0 ports on my ASUS FX53V, the Ni charges to full in just under 30 minutes. For nearly 10 hours of play time, that’s truly awesome and the convenience is unmatched among any other amp I’ve used.

Using It:

There’s not a lot to say about using the Nickel. Plug an aux cable into the input, plug your headphones into the output. It will automatically detect them and turn on as evident via the bright green LED located between the two ports. Just be sure to always plug the headphones in last else you experience a massive and unpleasant POP that leaves me worrying about the health of the headphones/earphones I just plugged in. As the batteries drain, the LED will change from green, to yellow, to red. When charging is needed, plug in the USB cable and wait 20-30 minutes. You don’t have to stop using the device either since it works while charging.

In terms of sound quality I found the Ni impressively balanced and uncolored. It doesn’t add in additional warmth or bass, jack up the midrange, or crank in extra treble. Using it with my HiFiMAN Megamini reduces the warmth of that DAP and as such I don’t feel the need to always pair it with neutral to bright earphones. Pairing it with a flawed budget offering like the Ruizu X02 doesn’t fix the early low end roll off of that device, but it does do an amazing job of correcting the harsh upper ranges. The Ni doesn’t “fix” the source device, but it can mask some of their shortfalls.

With more demanding to drive gear and/or that which benefits from amping such as the Brainwavz Alara, HiFiMAN Sundara, ADVANCED Alpha, etc., the Ni makes for an outstanding partner. The volume boost is only 6dB, but it allows you get to the most out of your DAP or phone’s standard output without having to worry about distortion should you push it. It results in good, clean power that allows you to listen at pretty much whatever volume you want. However, when pairing it with sensitive headphones like the Campfire Audio Solaris, Cascade, or TFZ Secret Garden HD, things aren’t quite as peachy keen. The source, be it a DAP, phone, laptop, etc. makes or breaks the experience.

I noticed there is always some hiss with sensitive headphones, and depending on the source that hiss is going to increase or decrease. My HiFiMAN Megamini, F.Audio S1, and HiFi E.T. MA8 all pair poorly with the Ni, MA8 in particular, adding quite a bit of extra background noise into the mix. My LG G5 and G6 fare better, akin to levels present when having earphones and an aux cable plugged in so the device is on but no music is playing. Noisy but plenty tolerable and masked when music is playing. My Shanling M0 really cleans everything up and is the best pairing of all my devices with the cleanest background of the bunch by far. The M0, Ni, and Campfire Audio Solaris together is a trifecta of perfection providing one of the most satisfying portable listening experiences I’ve had to date. The Shanling M1 and my PSVITA also worked well with the Ni.

Final Thoughts:

I’m somewhat torn on the Nickel. On one hand I love the tiny size and excellent driving power it outputs. The design isn’t particularly attractive, but it’s small and durable and the device is about as easy to use as it gets. No dials, no knobs, nothing to go wrong or fiddle with. On the other hand, the basic looking shell and lack of features like gain, bass boost, volume control, etc. make the 299 USD price tag difficult to justify. Until of course you look at the component parts and the engineering that went into making the device. That brings the price somewhat back into line with expectations. But then you experience severe and painful popping if you plug the headphones in before the source. Always go source then headphones. With the Ni there seems to be a lot of give and take. Lots of “X is great, BUT, watch out for Y.”

The size is very appealing though. I don’t like carrying around bulky, heavy, devices regardless of how competent they are, like the Auglamour GR-1. Amps that skew the sound signature, like the Walnut F1, reduce compatibility with various earphones and headphones since it risks boosting treble too much. None of this is an issue with the Ni though it is way more picky about earphone sensitivity, and especially the source device, when compared to any other amp I’ve used. When you start pairing the Ni with sensitive iems, you need to be very choosy about which source you use since there is a good chance the quantity of background hiss will be overwhelming. I’m lucky I have a number of DAPs and devices to mess around with since only a small handful of them retained a nice, clean background. The rest were noisy enough to require either an uncomfortable volume level to compensate, or were simply unlistenable, like the Solaris -> Ni -> MA8 combo. You can bring something like the iFi iEMatch into the mix to deal with the hiss but that negates the volume bump provided by the Ni. You also find yourself with a silly chain of devices that gets cumbersome to carry around, eating away at the size advantage and simplicity.

The Nickel clearly isn’t for those that like to tinker and toy with their sound. It’s an amp, and that’s it. The few features it has are convenient like auto-on/off and especially the impressive charge time. That said, it seems like a device made for someone already deeply invested in the hobby, not newcomers. Someone who has lots of sources and headphones can mix and match to find which pairings work best with the Ni. It would also be good for someone that listens primarily to headphones with lower sensitivity and higher impedance since the hiss issue is completely nullified, leaving you with a tiny, powerful amp that makes pretty much anything mobile.

I like the Ni and will certainly continue using it beyond this review, but it is tough to recommend to its intended audience; mobile users. Its pickiness with source when using sensitive headphones and iems, which most are when it comes to devices intended for mobile use, might be a deal killer. That said, if you’re interested in the Ni and plan to use it with headphones that require amping, go for it. You’ll be treated to a compact, powerful device with a flat signature, decent battery life, and an amazingly short recharge time.

Thanks for reading!

– B9Scrambler

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