PROS: AK4493EQ DAC, 2.5mm fully balanced output, smartphone and PC compatibility, wide soundstage, expanded dynamics, custom app to control the volume, budget price.
CONS: some “waterfall” hissing with sensitive IEMs.
The product was provided to me free of charge for the review purpose in exchange for my honest opinion.
As I started working on this write up, I tried to remember the last time I reviewed a compact USB DAC dongle. It has been a while, and there is a good reason for that. The sound quality of Android phones wasn’t that great 4+ years ago. Some manufacturers quickly recognized the demand, turning a smartphone into a touch screen digital transport to drive portable USB OTG DACs, and many audiophiles found it useful since touchscreen streaming DAPs were rare at that time. But as the sound quality of smartphones went up and Android support of high res formats improved, the interest in these dongles started to fade away, especially with more dedicated Android DAPs hitting the market.
So, imagine my surprise when out of the blue while waiting to receive their latest AMP9 w/Korg NuTube, I get a bonus DC01 dongle from iBasso. It was a surprise on many levels, maybe because I missed their upcoming products announcement or perhaps because I couldn’t understand why would a company with such a variety of Android and non-Android DAPs would release a USB DAC dongle? It wasn’t a question of a new product entering the saturated market (cause it’s not), but rather a question of is there even a demand for it? I know iBasso doesn’t put out random releases, so there had to be something special about this new DC01 USB DAC cable adapter. Here is what I found after spending the last few weeks testing it.
Unboxing and Accessories.
The unit arrived in a very compact cardboard box with a realistic 3D image of the device popping out from the cover sleeve. Despite small size of the box, there was plenty of info on the front and the back to highlight its functionality, design, and spec. The key features I noticed right away were a balanced output and AK4493EQ DAC which is quite unique for $49 device.
With a sleeve off, you’ll see a foam cutout with DC01 securely wedged inside and a flap covering the cable/connector portion of the device. As part of the included accessories, there was USB-C to USB-A short adapter and a detailed manual. It’s always nice to see manufacturers paying close attention to packaging details, regardless of the product’s pricing.
Design and Functionality.
DC01 main aluminum housing, kind of bulbous in shape, is about 38mm long, very lightweight, and hosts the 2.5mm balanced headphone jack, AK4493EQ DAC, dual ultra-low noise LDO voltage regulators, a blue led (to indicate the presence of power), and the rest of the circuit. A matching aluminum housing USB-C connector plug is attached with a short 8-wire braided cable, the same premium hybrid cable (4 pure copper and 4 SPC conductors) iBasso uses with some of their IEMs.
This interconnect cable will carry only a digital signal from USB-C connector to the DAC, but since we have multiple conductors, it allows to separate power, ground, and data signals, keeping them apart and isolated. Overall, this pigtail design looks very nice, especially when used with matching iBasso IEM cables. The total length of this pigtail adapter is about 120mm, and the total weight is about 10g.
Along with AK4493EQ, the spec mentions output voltage of 1.9V and output power of 113mW @ 32ohm load. Also, considering USB-C connection, it’s designed for use with Android phones/tablets, and with included USB-C to USB-A adaptor you can also connect it to your PC/laptop to use as an external USB DAC soundcard. With Win10 there is no need to install any additional drivers (confirmed on my Win10Pro laptop), but if you have an older version of Windows, iBasso has drivers for that.
With a smartphone, assuming you have the latest one with usb-C plug, you need to connect DC01 directly and it should be recognized right away. I was using Neutron app for playback, and had no issues with my Verizon Galaxy S9. Since there is no built-in battery, DC01 will be draining extra from the phone, but it wasn’t too bad. I noticed on my Galaxy S9 while using Neutron with WiFi/BT on, the drain was about 5% per hour when playing FLACs. With DC01 attached, under the same test conditions it went up to 9%.
Unfortunately, due to smartphone variations in hw and Android sw, there could be an issue related to inconsistency with max volume. To resolve this problem, iBasso released free UAC volume control app which could be downloaded from Google Play. It starts up every time DC01 is attached to the phone, allowing you to control the volume in 64 hw steps which helps to reduce the noise floor due to a finer volume adjustment within audio apps.