Headphone amplifiers are a difficult product to make interesting. If they’re working right, they should be forgettable – they should amplify an audio signal without adding distortion or coloration. Any purist will agree – the goal is “wire and gain,” and nothing else. Still, can be difficult to justify the price of these audiophile devices, so many companies add complexity with features, buttons, and exotic materials. We’ve even seen companies simply glue weights into their devices to make them seem of higher quality. Periodic’s new Nickel amplifier, however, does the opposite. The Nickel justifies its price with simplicity and competence.
The physical design of the Nickel is deceptively simple. Made of just two interlocking plastic parts, the Nickel is about the size of a 9V battery but, at just 20g, much lighter. The finish on our test unit was a little rough, with some small gaps, uneven seams, and a bit of looseness in how the internals sat in the housing. This is a little disappointing for a $300 device; hopefully its build is refined as production rolls on. That said, polycarbonate housing does keep weight down, and should make the Nickel resilient enough for mobile use (compare with the all-metal Oppo HA2SE that scratched almost immediately). If we could change one thing about the physical design of the Nickel, we’d ask for a thinner (even if wider) device, to make it more pocketable alongside modern smartphones. Other than that, Periodic has done a great job making the Nickel simple to use – clearly-marked 3.5mm audio in & out jacks, a multi-color LED to indicate operation and battery status, and a microUSB charging port. Interestingly, the cables included with the Nickel are TRRS – it will pass microphone input from your headphones to the phone, which is a rare feature in headphone amplifiers. There are no buttons or dials to manage – the Nickel turns on automatically when both input and output cables are connected, and turns off if one is disconnected. There’s no volume control either – the Nickel just provides a set 6dB of gain, so volume is controlled by your source device. Included with the Nickel are a short microUSB charging cable and 3.5mm TRRS (microphone pass-through) interconnect.
Inside the Nickel is the new Texas Instruments INA1620 amplifier. According to Periodic, the Nickel’s circuitry is EMI/RFI hardened and its power is isolated from the amplifier stage, which should eliminate interference from mobile devices and noise while charging. While we found this to be true in our testing, we did we did hear some familiar amplification hiss when paired with IEMs, including Periodic’s own “Be”. When we first heard about the nickel, we had to ask whether Periodic considered the non-ideal scenario of amplifying already-amplified audio from a cell phone. Dan from Periodic explained that the Nickel’s high 10,000 Ohm input impedance ensures that the amplifier of the source device is never stressed enough that it distorts, essentially eliminating the need for a Line signal. The Nickel’s advertised specs include frequency response of 8 Hz to 80kHz, SNR of 105 dB, THD of less than 0.005%, greater than 80 dB of channel separation. This little amp will output 250mW into 32Ohm for up to 8 hours on a charge (recharging its 280mAh battery in just 30min). In our testing, we found the Nickel to be exactly what it’s advertised to be – a very powerful little amp. It obviously had no problem driving IEMs, but it also drove the 70mm drivers of the Sony Z1R (64Ohm, 100dB/mW) with ease to too-loud volumes with great articulation and complete transparency.
The Periodic Audio Nickel is the epitome of a unitasker. It does one thing, and does it well. It’s a tiny, deceptively-simple amplifier that hides all its smarts under an unassuming plastic shell. We have tested many portable amplifiers over the years, each with its own strengths, weaknesses, and feature sets. Periodic has, apart from making a very competent amplifier, made one of the most portable amplifiers we have yet to try. If you have room in your pocket for a 9-volt battery, you have room for great sound. We highly recommend the Periodic Nickel.