NiPO A100

A-Perfect sound score!

PROS: Big soundstage expansion, neutral engaging tonality, expanded sound dynamics, pitch black background, built-in battery with a decent playback time, high output power and current drive, magnetic (MagSafe) rear panel, and included high-quality USB-C/Lightning OTG cables.

CONS: Only works from internal battery, can’t charge during USB/DAC operation, no volume level indication, and limited battery level indication.

The product was provided to me free of charge for review purposes in exchange for my honest opinion.

The manufacturer’s website: NiPO. It can be purchased from authorized retailers, such as Musicteck.

Intro.

These days, I find the “dongle” business going through another wild roller-coaster ride. Many years ago, the concept became popular due to the marginal sound quality of early smartphones, then as a replacement for disappearing headphone jacks, followed by the convenience of not needing to carry a separate DAP in addition to your smartphone, and now with manufacturers trying to get more creative to distinguish themselves from a saturated crowd of other dongles. Part of this creativity involves competing not just with entry-level DAPs, but aiming higher, including greater output power and room for more analog components. As a result, these devices are becoming bigger, by including the batteries to prevent excessive drainage of the mobile source, and enhancing the output power not only on paper but in practice, by being able to drive more demanding loads.

I mentioned in one of my recent reviews that it is becoming hard even to consider these new devices as a traditional “dangling” dongle because of their size, added functionality, and improved sound quality on the level of more powerful, transportable USB-DAC devices, which you typically don’t carry in your pocket along with your smartphone. Furthermore, considering the popularity of MagSafe accessories, which are no longer limited to just iPhone devices, but are also being used with the latest Samsung Galaxy phones with their magnetic cases aligned with Qi charging, I see more manufacturers taking the opportunity of this convenient mounting option. With a bigger size and heftier weight, a dangling-dongle is no longer a practical solution, while the rubber band mounting option is a thing of the distant past.

While I wasn’t very familiar with the NiPO brand, a newcomer which I believe debuted last year with their N2 DAP, I became curious about their latest A100 USB-DAC dongle, released in collaboration with Musicteck as a Special Edition. Actually, after the initial A100 introduction, as Musicteck became NiPO’s distributor in the US, Leo from Musicteck suggested a few improvements to their design, such as customized capacitors and a replacement amplifier opamp chip, resulting in an updated sound tuning and improved technical performance. The A100 MT Special Edition release was so well-received that NiPO decided to move forward with it exclusively, replacing their original design. This is why they still refer to it as the A100, because it is the only model available for global sale.

Now, please sit back, relax, and enjoy my take on this latest A100 release from NiPO, brought to you with a helping hand from Musicteck (Leo, you are on a roll!).

Unboxing and Accessories.

A100 arrived in a compact box, featuring modest cover art on the exterior cover. Under the cover of the box, this USB DAC was sitting on the top tray, shining in a secure foam cutout. Underneath, once the tray is removed, you will find the accessories and the multi-lingual user’s guide with a lot of helpful info, including a separate user’s guide brochure focusing specifically on the charging details.

The accessories included O-shape & C-shape magnetic stick-on rings for a source that doesn’t support MagSafe magnets. If you have an iPhone or a Samsung Galaxy phone with a magnetic case, this shouldn’t be a problem, but for older devices or if you want to have A100 attached to the back of your DAP, these could come in handy. Also included were the USB-C to USB-C and USB-C to Lightning OTG cables. These cables were of high-quality construction, featuring durable connector housings and cable shielding. They were slightly rigid yet still flexible enough for use with a device attached to the back of the smartphone.

Design.

While A100 is not as small as a typical dongle, it remains compact, measuring 94.5mm x 61mm x 10.8mm, and is relatively lightweight at 131g, slimmer than a deck of cards. It has a solid build and features a unibody aluminum alloy chassis. I have a regular Galaxy S25 phone, not the Plus or Ultra, which supports wireless charging, and my UAG case already features a built-in magnet similar to MagSafe. Considering the regular size of my S25, the A100 width is even narrower than the phone’s case width and is approximately two-thirds of its length. This allows it to be hidden behind the phone when piggybacked without blocking the two top lenses of my phone’s camera.

The chassis is in a golden color, featuring a photolithography non-textured finish treatment, which creates a unique swirling visual effect. The magnetic side features N52-Grade Neodymium magnets that attach firmly and feel secure on the back of my S25. The opposite side of A100, facing outside, features a piece of glued leather material that adds texture and color to the design. It enhances the grip, creates a non-slip surface, and protects any surface it comes into contact with from scratches. You get a choice to pick the A100 model with either black, orange, or teal color leather.

At the bottom of the device, you will find 3.5mm SE and 4.4mm BAL phone ports with a USB-C data/charging port in the middle. The USB-C port features a slim LED light around it that remains visible even when the cable is plugged in, indicating the battery status. It turns red when you start charging the device (after double-pressing the power button). Also, remember to give it another 30 minutes to charge after the light turns green to make sure it is fully charged. The LED also indicates a battery level:

Green – above 90%
Orange – between 40% and 89%
Red – between 1% and 39%

This battery indicator is somewhat limited, and I would have preferred a more common 4-LED indicator in 25% increments. But it is what it is. The design only allows charging A100 when it is not in use, meaning you can’t charge it during playback. I find it helpful when using a Smartphone, as it ensures you don’t drain its battery while using A100’s internal battery. However, when using A100 as a USB-DAC connected to your laptop, you will need to either stop playback or wait until the battery is in “red” status, as you can then unplug it and charge it.

The button controls are located on one side, to the left when facing A100, with the magnets facing you. There are four solid metal buttons, flush with the chassis. The power button is located at the top, positioned further away from the volume up (+) and down (-) buttons, which are clustered closer together below. Additionally, the “+” button features a braille bump dot. Then, the G gain/filter button is positioned below it, also with a braille dot, accompanied by a pinhole LED indicator underneath. The power button is used with a long press to turn the device on/off, and a double press to start charging when not connected to the source. While there is no display and no volume level indicator, upon startup, I noticed the volume is always set to a lower level by default, so there are no ear-shattering surprises.

Long-pressing the G-button switches between low and high gain, and the device always starts in low gain after powering up. When switching to high gain, the LED indicator will light up. Short presses of this button switch between ESS DAC filters, while a double-press of the G-button resets it to a default filter. The filter setting is cycled in the loop as follows:

minimum phase (default)
linear phase apodizing fast roll-off
linear phase fast roll-off
linear phase slow roll-off low-ripple
linear phase slow roll-off
minimum phase fast roll-off
minimum phase slow roll-off
minimum phase slow roll-off low dispersion

I tried listening very closely to the changes between these filter settings, but didn’t hear any noticeable difference. I will leave it at that, for others to try it and see if they hear anything. It’s just another option to access digital filters built into the ESS DAC.

Under the Hood.

In the heart of A100, you will find the ESS ES9039Q2M DAC. The original design of A100 featured an AD8397 opamp used in its headphone amp design. After the A100 introduction, Musicteck approached NiPO with suggestions for the design improvement, featuring a customized capacitor matrix design and the replacement of AD8397 with an upgraded, ultra-low-noise SGM8262 opamp chip. It is essential to note that the current A100 design is a special Musicteck Edition, and I was told that this is the only version of A100 NiPO that will be manufactured moving forward.

The signal path of the design starts with USB Isolation, an integrated magnetic isolation to prevent interference with the electronic circuit, followed by Data Reconstruction and USB Decoding, sending the digital data into the DAC. The analog output of the DAC goes through NiPO’s ultra-linear single-stage gain design headphone amplifier circuit. This block consists of a self-developed fully discrete CMMT Current Mirror Technology I/V conversion circuit, low-pass (LPF) filter, and voltage amplifier (based on SGM8262).

The output spec of the amplifier section of the design is as follows: 3.5mm SE, 2V output, 0.22ohm output impedance, and 125mW @32ohm; 4.4mm BAL, 4.1V output, 0.44ohm output impedance, and up to 525mW @32ohm. The half-watt of power is based on balanced output at high gain, driving up to 300mA of current. The output is optimized for both low-impedance/high-sensitivity IEMs and high-impedance/low-sensitivity headphones, all of which I’m planning to test in the follow-up section of the review.

Furthermore, as I mentioned earlier, A100 features a built-in battery, which serves as its sole power source. This approach prevents draining your smartphone’s battery and ensures a stable power supply through effective filtering. It features a 3900mAh battery, with an impressive playback time of approximately 13 hours from the 3.5mm output and nearly 9 hours from the 4.4mm output.

Overall, the design is rather minimalistic, with no LCD or many settings. The focus is on sound performance and the main functionality when paired with a smartphone, although you can use it as a USB-DAC with any source.