Periodic Audio Rh

Package is simple and eco-friendly inside is the DAC and a USB C to A adapter. The cable is fixed and non-removable for this price this is acceptable, and it's made from a durable nylon braided cable so it should last a long time if treated well.


Frequency Response

2 Hz to 192 kHz, +0/-3 dB

Dynamic Range

113 dB

SNR

108 dB A wt.

THD

Less than 0.007%

Continuous Output (RMS)

31 mW @ 32 Ohms - Per Channel

Dynamic Power Output (Peak)

62 mW @ 32 Ohms - Per Channel

Physical Properties

Cable Length

63mm

Mass

4.4 grams

Operational Temperature

-20 to +50° C

Operational Humidity

0 - 95%

Retention Force

1.8 Newtons

Overall Length

117 mm

Max Width

10.8 mm

Max Thickness

6.9 mm

Material Properties

Melting Point

2237 Kelvin

Speed of Sound

4700 meters per second

Young's Modulus

380 Gigapascals

Brinell Hardness

1100 Megapascals

The sound: The DAC presents rather neutral there is a little hint of warmth in the lower mids but it's hard to pinpoint such thing, as so many factors and devices differ ultimately the Rh presents with a fair amount of clarity and details, it has a smooth enjoyable sound.

Conclusion: The Periodic Rh is energy efficient and easy to use and provided a noticeable increase in volume and clarity on many devices. It is fairly low powered so no full sized or higher than 32-Ohm should be considered, and I would recommend lower for optimal use 18-22. Still this easy to use and carry and doesn't cost too much so I think it would be good paired with an amplifier for daily use.

Periodic Audio Rhodium Dongle DAC - Diminutive Music Shaper



Priced at 49 USD, Rhodium is one of the smallest and discreet dongle DAC/AMPs made to date, with 32Bit / 384 kHz decoding abilities. It features a fairly low power output, of 31mW, so it will be suited for usage with IEMS and portable headphones.

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Introduction

Periodic Audio is a company that offers excellent performance for their IEMS, but also good technical background information. They created some really unique products over the years, and I will be reviewing the upcoming Periodic Audio IEMs with detachable cables in the near future as well. The company has good support for their customers, and is in the list of recommended companies for me.



It should be noted that I have absolutely no affiliation with Periodic Audio. I'd like to thank Periodic Audio for providing the sample for this review. This review reflects my personal experience with Periodic Audio Rhodium Dongle Dac AMP. Every opinion expressed is mine and I stand by it. The purpose of this review is to help those interested in Periodic Audio Rhodium find their next music companion.



Packaging

First things first, let's get the packaging out of the way:











The package of the Rhodium is fairly simple, and it includes the dongle DAC/AMP, and a typeA to typeC adapter. This is the smallest dongle I have reviewed to date, and the lightest one, so the package being tiny is no problem, especially for the price. The package is vertical and looks a bit like what you'd see for a multivitamin supplement, so make sure to not lose the Rhodium package when handling it, or your grandfather may become more musical than he ever was.



Build Quality/Aesthetics/Features

To use Rhodium, you just plug it in either your smartphone, or your computer, and it basically works. It is an active DAC chip, so it has its own DAC / AMPs and capacitors, working with basically all the smartphones and computers I tried it with. No additional drivers are needed for windows 10 at the moment of writing today's full written review.



The chips inside Rhodium are more of a mystery, but they have been identified as Realtek ALC5686 SoC, a component that has been used with other high-end audio capacitors in computer design. Rhodium is a TRS device, single ended, and will work well for smartphones that have no Type-C port, or computers / laptops where the audio jack has a poor quality (most of them do).



We have support for PCM signals only, with PCM support up to 384 kHz / 32 Bit, and while I like to push new technology like DSD and DXD, and MQA, I personally do not use them very much, since most of my music is not available in those exotic formats. In fact, almost my entire library is made of redbook flac files that I ripped myself, and most of those CDs aren't even available for purchase anymore, let alone in MQA or exotic formats. While you can set up Foobar2000 and other players to decode DSD and deliver it via PCM, for the vast majority of users Rhodium will be adequate, and for those who need MQA and DSD, there are alternatives for a higher price.



Rhodium has a rather low power output, and with 31mW of power, it will drive mostly IEMs and portable headphones, plus the best sound can be found at average listening levels, rather than loud. The low 0.007% distortion, and high 113 dB of signal to noise ratio are excellent, for a unit that is so low. The power consumption of Rhodium is incredibly low, and it does not change the battery life of my smartphone in any way, with a 23mA constant power draw. It weights 4.4 grams, being one of the lightest DAC/AMP dongles I tested to date.



Sound Quality

The sonic performance of Rhodium is good, and it has a pleasant, warm signature, with some midrange forwardness, but good background nuance and detail, all within a flat frequency response. To take today's impressions about the Rhodium, I've been using exclusively IEMs, and those include Tin T3 Plus, Dunu Falcon Pro, IMR Audio Ozar, Campfire Mammoth, Earsonics Corsa and QoA Queen Of Audio Adonis.



The bass of Rhodium has a flat presentation with lesser impact, and this is one of the places where you notice the lower power it delivers, but the bass has good nuance and definition. The bass has good warmth in the upper bass, and you can totally listen to EDM, Pop and Electronic with Rhodium, but the best performance is with Jazz, Country and Acoustic music, where the overall warmth and pleasing tonality creates a really relaxing listening experience. The overall speed of the bass is slow, which means long note decay and slower impact.


The midrange continues this fashion, and it is presented smoothly, clean, and with good timbre and pitch. The midrange is slightly forward, with a good amount of detail, and Rhodium is surprisingly wide for the signature and size it has, having a good depth and width, presenting music in a very 3D style. Despite the rather low power it has, the dynamics are great, and Rhodium provides a good depth and distance between you and the singers from your favorite songs. I would call the midrange organic in nature, and it is a breath of fresh air, compared to brighter and more peppy DACs / dongles like Beam 2 from Audirect.

The treble of Rhodium rolls gently, and has a lower presence, leading to a smooth and relaxing top end, with a good amount of clarity and air. The sound is well controlled even at high volumes, and it can push some high decibels into the IEMs I used for testing it, plus it has low background noise and hissing. Rhodium pairs well with brighter IEMs, and with IEMS that are easy to drive, like Tin T5, or FiiO FH5S, and even dd hifi Janus, as it stays controlled and relaxing with those.



Value and Conclusion

For the 49 USD price point, Rhodium is an excellent dongle / dac / amp purchase and it provides a natural, refined and relaxing sound, with enough power for IEMS and portables. It has one of the lowest power draws of all dac/amps, and it will be the perfect partner for long trips, especially if you don't have access to power, and want to enjoy your music for long hours. If your smartphone does not have a 3.5mm single ended jack, then Rhodium will be the perfect partner, and if it does, Rhodium will sound smoother, warmer and more relaxed than your smartphone, so it will still be an improvement, especially if you're using bright and shouty Chifi IEMS.



At the end of today's review, Periodic Audio Rhodium is one of the most relaxed, smoothest and most organic sounding dongle DAC/AMPs, and it most certainly is one of the most energy efficient ones, and a fully recommended purchase if you're looking for a pleasing and warm sound.



Specifications

• Frequency Response - 2 Hz to 192 kHz, +0/-3 dB
• Dynamic Range - 113 dB
• SNR - 108 dB A wt.
• THD - Less than 0.007%
• Output Power - 31mW @ 32 Ohms
• Current Consumption - 23mA @ 1mW output
• Cable Length - 63mm
• Weight - 4.4 grams
• Operational Temperature - -20 to +50° C
• Operational Humidity - 0-95% Relative Humidity
• Overall Length - 117 mm
• Max Width - 10.8 mm
• Max Thickness - 6.9 mm

disclaimer: The Periodic Audio Rhodium was provided for review by Periodic Audio. I have no financial interest in Periodic, nor have I received any payment beyond the test unit itself for this review. If you have an interest in learning more about Periodic Audio products, See their website and Facebook. Right now Periodic has a promotion for Father’s day that includes a free Rhodium with purchase of a Carbon in-ear and Nickel Amp.

Packaging:
Packaging is very simple with a white card stock box with black lettering and the periodic table style layout we have come to expect from PA. Inside the box, we find the dongle itself and a USB type-C to type-A adapter. No USB to lightning adapter is provided and the Periodic website is quick to note that even with the camera kit, the Rhodium may not work with apple devices so this is best used for android, windows, Linux, and mac-OS where it is detected by plug and play and works well.




Build:
The dongle itself is tiny and one would be forgiven for assuming there was no dac in it as it seems there simply is not space to accommodate one. At the south end, we have a USB type C connector in a black polymer housing with a short strain relief then at the opposite end of the cloth wrapped cable we have a a round housing for the 3.5mm port. Again a short strain relief is provided. Overall length is just short of five inches with the USB connecting being just under 1 inch in length, three eighths of an inch wide, and roughly one quarter inch thick. The 3.5 port is also roughly one inch long with a quarter inch diameter. As suggested, this leaves little room for anything internally as space is certainly at a premium. The good news is the dongle weighs almost nothing and certainly wont be something you have to contend with when on the go.





Internals:
Periodic doesn’t list the chip used inside the Rhodium but a little digging using android and linux USB tools identifies the chip as either a Realtek ALC4042 or ALC4050. I have attached both datasheets for those interested in more details. Regardless of which of these two codecs is in use, the dongle supports up to 32bit / 384kHz PCM but does not support DSD or MQA which is a bit limiting by today’s standards. The specs list 31mW @32Ω which makes this best reserved for in-ears or extremely efficient headphones. I tried the Rhodium with several different models just to see how far I could push and definitely found some limits. Beyerdynamic’s 600Ω DT990 is definitely out as the Rhodium simply doesn’t have enough usable volume range for this. The HD6xx was better but still lacked enough volume range to really be useful. If I maxed out the volume, I could reach a comfortable listening level, but it had no headroom left for a crescendo at that point. With iems it fared a good bit better with the exception of the TinAudio P1 and the Tri I3 where it again struggled to have enough power to push them to full capability. Periodic markets the Rhodium as a pre-amp rather than a DAC/Amp which is probably a good way to think of it as alone it lacks the potency to drive all but the most sensitive of in ears. On the plus side, there was no his with my Magaosi K5 which is notoriously sensitive so it pairs well in those instances where more power is a drawback.


Sound:
It can be hard to determine exactly what any dac/amp brings to the mix as so much is dependent on source and headphones in use. The Rhodium does have good detail and clarity, but lacks some impact in the lows especially when paired with anything it struggles to drive. I found the Magaosi K5 paired well and had good detail retrieval, nice crisp mids, and acceptable bass (it never has a ton here anyway), but as I moved to harder to drive models, it quickly became evident that the Rhodium is meant as a pre-amp and not as a dac/amp by itself. When used with an amp following and thought of as a dac only, the Rhodium does a good job of staying neutral and rendering detail well.


Conclusions:
With makers coming out of the woodwork to provide USB to 3.5mm jack dongles for the cellphone market, it is no surprise that Periodic felt the need to have a model of their own to complement their in-ear offerings. The Rhodium offers a good level of detail and a quality build and does pair well with the Beryllium and Carbon models and the low output power does mean it helps conserve your phone battery which is a good thing if your in-ears don’t need additional power. The downside to that limited output is it either needs to be paired with an amp or doesn’t have the potency to drive over-ear models or high impedance / low sensitivity ear buds. This makes it a niche player at best as too many other dongles offer those features at nearly the same price. Periodic does market the the Rhodium as a pre-amp and even goes so far as to package the Rhodium with the Nickel amplifier and Carbon in ear as a kit and this is likely the best use case for the Rhodium as it functions well as a dac but needs a potent amplifier to complement it.