Periodic Audio Carbon IEM‌‌ And Nickel Headphone Amplifier Review- This Extraordinary Combo Will Give You Goosebumps!

Periodic Audio “Carbon” Diamond Diaphragm Audiophile in-Ear Headphones

Periodic Audio “Carbon” Diamond Diaphragm Audiophile in-Ear Headphones







What We Dig

  • Comfortable Fit
  • Smooth Treble
  • Fast, Dynamic Sound

What To Think About

  • Plain Jane Looks

Periodic Audio has been on my radar for a few years now, but I haven’t had a chance to spend much time with the product outside of some brief encounters at audio shows. Their booth is always buzzing, and people get excited about their IEMs, so I always wanted to put a pair through its paces.

Well, I have the good fortune to review not only any pair of Periodic IEMs but I’m reviewing the most expensive pair, the $399 Carbon IEM. I‌ also have their itty bitty Headphone Amp, the $299 Nickel Portable Headphone Amp, so I will touch on that as well.

Both items were sent out to me in exchange for an honest review, and that is what follows.

Build and Features

If you’re not familiar with Periodic Audio, they’re a U.S. based company that makes earphones and other portable audio gear. All their stuff is at least assembled in the U.S.A, which is pretty rare nowadays. They’re primarily known for IEMs, and each In-Ear Monitor features a driver incorporating an element from the Periodic Table. Hence the company name.

It’s a novel idea. Their overall design philosophy is novel, as well. Unlike most companies, they don’t attempt to develop several different earphone designs, which become increasingly elaborate as you go up in price.

Instead, they use the same zero resonance polycarbonate housings, cables, metal logo caps, and Neodymium iron boron magnets throughout the line, just changing the colors and diaphragm treatments.

In the case of the Carbon, the diaphragm is coated with an 8-micron layer of lab-grown diamond to provide stiffness. This, in theory, should reduce distortion during playback.

The choice to use the same components in their $399 IEM‌ as they do in their $99 IEM has some logic to it. As they say, “if it ain’t broke, don’t fix it.” They do have a good design foundation.

The problem is people aren’t used to $399 earphones that look like $99 earphones. Regardless of how well thought out the design is, at first glance, the plain all-black motif makes the Carbon look like something you would pick up from a local Walmart as opposed to a serious audiophile In-Ear Monitor.

It might’ve helped if they made the metal end cap a color other than black. The models below it have Silver and Gold caps that make them look more expensive than the flagship model. After reading through some impressions on the headphone forums, I know it’s an issue for at least a few.

That being said, these earphones are probably a prime example of why you shouldn’t judge a book by its cover. That’s because the ergonomics of their IEMs are excellent. The straightforward fit is comfortable, and it’s nice not having to fuss with ear hooks for a change.

The polycarbonate housings are light, and the metal caps on the end act as counterweights balancing the IEMs perfectly in your ear. The cable is thin but tangle-resistant, and it’s just the right length (1.5m) to allow freedom of movement.

Noise isolation is also excellent. I didn’t hear much outside noise when I‌ had them in.

This IEM‌ would probably be a great pick for those who say IEMs are uncomfortable. They are that comfortable and easy to wear.

The sound is also top-notch, which I’ll get to in a moment.

As far as accessories are concerned, you get a metal screwtop can to put the earphones in, nine sets of ear tips (three double-flange silicone, three silicone, three foam), plus 1/4″ and Airplane plug adapters.

If I had any complaint about the design, it would be there’s no clear indication of which earbud is left or right. The only way you know is by looking at the inside of the nozzle. On the right side, the interior mesh is colored red.

Listening to the Carbon IEM and Nickel Portable Amp

I‌ began my listening tests by plugging the Carbon directly into my LG V40 Phone with the ESS Quad-DAC, which incorporates a 2V Headphone amplifier. It sounded good connected directly to the phone, but then I wanted to get Periodic Audio’s Nickel headphone amp in the game.

I was wondering why they would suggest an external headphone amp to use with these IEMs, but after using it, all my questions were answered. First of all, I‌ feel like I need to describe the Nickel and its attributes to give some context.

This Amp is like nothing I’ve seen before. First of all, it’s tiny. It’s housed in a black plastic box about the size of a 9-volt battery and rated to provide 250 mW continuous into 32 Ohms. This thing drove my Mr. Speakers Aeon Flow Closed (92dB/mW Sensitivity, 13 Ohms Impedance) very loudly and clearly at about 75% volume on my phone.

By the way, the Nickel has no volume control of its own; it depends on the source device for that. It’s a pretty simple device. There’s no on/off switch; it turns on automatically when you plug in both the earphones and the source using the included 3.5-inch to 3.5-inch mini cable.

There is a small LED on one side that lets you know when it’s powered up or charging and a micro-USB‌ connector on the other side for charging the internal battery. The battery is rated for eight hours at a loud listening level with their IEMs.

After listening to the Carbon both with and without the Nickel, I see why they sent it.

With a 98db Sensitivity and 32 Ohms impedance, you will have no problem driving Carbon with any portable device, but with amplification, especially the Nickel, they come alive with crisper highs and tighter bass. The amp will increase your enjoyment if you have an underpowered source.

However, since I know a lot of people will want to know how they sound without the additional $300 amp, I will give the rest of my impressions with them connected directly to the Fiio M11 Pro Digital Audio Player using TIDAL‌‌ HiFi. I chose it because it has a great amp of its own. (specs on the DAP listed here)

If I‌ had to describe the overall sound of the Carbon in a few words, I would say it’s an experience of refined fun. They don’t go for a flat audiophile signature, but at the same time, they don’t have the sizzly highs and boomy bass of a mass-market earphone.

Like a lot of IEMs ‌I’ve listened to lately, they seem to put a slight emphasis on the bass and treble, in turn relegating the mids to the rear just a little bit. This choice appears to be a compromise between a flat (some may say boring) audiophile reference and some added excitement.

As such, the Carbon plays well with fast, modern, music like the UK‌‌ Jazztronica that’s all the rage these days, or some good old Daft Punk. They don’t sound bad with any genre, but singer-songwriter or Jazz music based around vocals sounds subdued in comparison to the other music.

Listening to “Alonesome” by Malin Pettersen, which is a stripped-down song with just vocals and guitar, the guitar was very lively with strings having a beautiful delicacy to them. They sounded very natural. The vocal, however, was a little restrained for my taste, even though it was clear.

I would’ve also liked a little more soundstage and air; I found the stage to be a bit narrow, without as much layering as I‌ would’ve liked.

When I‌ listened to “Touch”‌ by Daft Punk, it seemed to be a song more in Carbon’s wheelhouse. While I‌ again wished for more openness, the song played fast and expressive, and all the elements were separated cleanly. Bass was also fast, tight, and articulate, no boominess at all. The Bass depth was impressive. Carbon is very Dynamic. I‌ don’t know if I’ve heard an IEM‌ this dynamic before.

When I‌ compared them to the Simgot EK3, a $359 IEM, I found the Simgot to have a wider soundstage, better layering of instruments, and more expressive vocals. However, they didn’t have anywhere near the Dynamics and bass slam of the Carbon. The EK3 was a lot leaner in comparison.

The EK3 treble was also a little brighter and not as smooth as the Carbon, but I‌ think that gives the Simgot IEM‌ a bit more air. However, I dare to say the Carbon sounded a little more natural overall.


If you can get past the Plain Jane looks, the Carbon has a fast, dynamic sound that will please those who want some detail and refinement with their fun. They sound even more refined with the Nickel Amp. The comfortable, straightforward fit may also please those who don’t like the fit of the standard over-the-ear type IEMs that are all the rage today.

Buy Here: Amazon-Periodic Audio “Carbon” Diamond Diaphragm Audiophile in-Ear Headphones Assembled in the USA

Buy Here: Amazon-Periodic Audio Nickel portable high-power headphone amp, battery-powered, USB charging

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