The iBasso DC04PRO was kindly provided free of charge in exchange for an honest review. I didn’t receive monetary or any other kind of compensation and I don’t use affiliate links. The price of the iBasso DC04PRO is $119 and you can buy it from iBasso-shop.eu.
iBasso DC04PRO
The iBasso DC04PRO is the latest USB DAC dongle by the company, the successor to the now discontinued iBasso DC04 and a step above the iBasso DC03PRO.
Technical highlights
The DC04PRO combines many well selected parts and advanced technologies, such as dual CS43131 flagship DACs, dual RT6863 high current output OPAMPs, synchronous DC-DC converter, ultra-low noise LDO, FPGA, KDS Femto second oscillator, multi-functional APP, pentaconn 4.4mm balanced socket, CNC aluminum case, and tempered glass panels. All of these are forged into a USB DAC & AMP with high output power, high current output, dual output interfaces, interchangeable cables, excellent power consumption control, and outstanding specs.
The Cirrus Logic flagship DAC CS43131 provides outstanding performance and excellent sound. With the ultra-low noise LDO that has a 100dB power supply noise rejection ratio to ensure the power purity for the DAC chips, results in an amazing sound quality with a superb black background for the DC04Pro.
The quality of the power supply directly affects the sound quality in no small way. DC04PRO utilizes a synchronous DC-DC converter and low-noise high-speed LDO, ensuring sufficient high purity power for the dongle, bringing a dynamic and powerful sound to your music.
The DC04PRO utilizes dual RT6863 chips, creating a 4-way fully balanced amp featuring ultra-low distortion. With an output current of up to 100mA and working at a 10V voltage swing, the DC04PRO output reaches 280mW@32Ω. There is also a Turbo mode that outputs about 1/3 more power but uses more battery current.
iBasso have developed their own FPGA algorithm and for the first time it is used in a dongle. Together with the KDS Femto second oscillator, jitter is well controlled, and sound reproduction becomes more distortion free, enhancing the sound quality.
The innovative power saving mode
The iBasso DC04PRO is the only DAC dongle in the market with an innovative power saving mode that helps it to consume less power depending on the use conditions.
According to the manufacturer, when using normal mode balanced output, the power consumption is 650mW. The single-ended output will automatically turn off the unused half of the amplifier, lowering the power consumption to only 550mW. When the power saving mode is on, it turns off and bypasses the AMP section, with output directly from the DAC’s internal amplifiers. In this mode, the power consumption is as low as 410mW. Compared with the power consumption of similar dongles, which can be as high as 700 to 800mW, the power consumption and heat generation of DC04PRO are lower, enhancing long-term listening. You can engage the power saving mode from the iBasso UAC application that is only available for Android users. The total power output and voltage swing of the DC04PRO remains exactly the same in either mode.
Power consumption
I have performed my own measurements using the iBasso SR3 (150Ω) from the balanced output. Host device volume was set to maximum and that of the DC04PRO to 85 of 100. Gain High and Turbo mode ON. Streaming high resolution 24bit/96kHz files from Qobuz yielded the following numbers: Power saving mode ON: 0.09A, 0.5W – Power saving mode OFF: 0.14A 0.73W. For comparison the FiiO KA5 will consume 0.12A/0.62W and the iFi Go bar 0.14A/0.71W under the same working conditions and volume level roughly matched by ear so the iBasso DC04PRO is really efficient.
Build quality and appearance
The iBasso DC04PRO has the same design and appearance with the DC03PRO except that it is slightly bigger and heavier. The DC04PRO case is made by using CNC to precisely manufacture the high-grade aluminum alloy. The open volume control structure requires complex steps during machining, which is both visually appealing and fits with required function. Using tempered glass panels at both sides, the DC04PRO is both aesthetically appealing while conveying the quality of build. Grey and Blue colors are available to meet individual preferences. Build quality and finish are simply excellent.
Accessories
The iBasso DC04PRO comes bundled with a short USB C to C cable and a full size USB adapter. It seems that iBasso have also decided to add a lighting cable for free that wouldn’t fit inside the package so it is included in a small plastic bag attached to the box. For even better sound quality you can buy the iBasso CB18 USB C to C upgrade cable.
User interface
The iBasso DC04PRO is plug-and-play on Android smartphones and tablets with Android 5.1 and above without installing drivers or third-party applications. On some Android devices, it may be necessary to manually turn on the OTG function in the system settings. The DC04PRO is also plug-and-play on Mac and Win10 computers. For WinXP, Win7, and Win8 systems, you will have to download the driver from the iBasso website.
Once properly installed you can use the DC04PRO as a USB sound card and you can control the volume from the hardware buttons. The iBasso DC04PRO can achieve 100 steps of adjustment with the volume buttons allowing for finer volume adjustments than the host device. The iBasso DC04PRO supports PCM up to 32bit/384kHz and DSD256. A tiny notification LED will light red for standby, green for PCM and blue for DSD decoding.
The iBasso UAC application
The iBasso UAC is a self developed application that allows for further customization of the DC04PRO. It bypasses the host device’s internal volume control and allows for a 100 steps of precise hardware volume adjustment. The user can also select between the 5 different low pass filters, three gain settings (high, medium and low), 20 steps of left and right balance, enable or disable the power saving mode and engage the turbo output mode. A very handy application which, unfortunately, is only available for Android. The settings are not permanently stored in the DC04PRO ROM so you can’t use an Android device to configure the iBasso DC04PRO and then use the settings in another platform. For Windows, Mac and iOS, the DC04PRO will always use the default settings which are: Low pass filter 1, High gain, Turbo mode on and power saving mode off.
Power output and noise floor
The iBasso DC04PRO is powerful and the performance is close to the limit of what an op-amp can do from the limited 5V power supply. The manufacturer states that from the balanced output you get 280mW/32Ω which is just a bit higher than the 265mW/32Ω of the FiiO KA5. Plenty of power to drive a variety of full sized headphones, like the iBasso SR3 and the Sennheiser HD660S2. At the same time the iBasso DC04PRO is really silent, there is no EMI noise so you can use it with your sensitive earphones.
Listening impressions
If you are familiar with the latest USB DAC dongles and DAPs of iBasso then you will not be surprised by the musical, balanced and natural sound signature of the DC04PRO which also combines great technicalities and transparency. The sound is crystal clear and transparent with a linear frequency response, exemplary source fidelity and great engagement factor.
The bass is deep and controlled with excellent definition and tightens, it is fast and full bodied with good physical impact and contrasted dynamics. There is plenty of power on tap and with the right headphones you can enjoy undistorted and thundering bass even when you reach for the maximum volume setting. The iBasso DC04PRO can handle all kinds of music, from EDM and bass heavy tracks to classical music with very competitive technicalities.
The mid-range is natural and engaging with good timbre realism and linearity. The sound is more organic than similar USB DACs with ESS chips, instruments and voices are rendered in a realistic manner with plenty of harmonic variety without lacking in clarity, layering and definition. The texture is lush and full bodied, the listener gets emotionally connected with the music, the DC04PRO is very expressive and by no means sterile or cold sounding.
The CS43131 NOS filter lowers digital glare and ringing by a fair margin. This is especially audible in the treble which doesn’t sound artificial or metallic and it doesn’t cause listener fatigue despite being clearly defined and well extended. The DC04PRO is fast and sparkling, this is a high spirited and energetic DAC, the sound is luminous and crystal clear with satisfying detail retrieval and at the same time it is rather smooth and certainly without brightness or any kind of harshness. The overall transparency of the DC04PRO is impressive so you better remember that it can become rather unforgiving to source quality, it will not smooth out anything or mask recording deficiencies.
The DC04PRO soundstage is open and spacious, with sharp imaging and excellent layering for the category, it also presents the music in a holographic and immersive manner. Fans of grand soundscapes are going to thoroughly enjoy the iBasso DC04PRO as I did when I was listening to this recent recording of Saint-Saens symphonic poems.
Power saving mode ON vs OFF
I am pretty sure that many readers are going to ask about the sound differences between the two power saving modes, how the DC04PRO sounds with or without engaging the dual RT6863 chips.
The sonic differences between the two modes are rather subtle and mostly concentrated in technicalities. The overall sound signature remains pretty much the same but, when engaged, the extra amplification stage adds better drive and grip, the sound becomes more dynamic, the bass is a bit more impactful and the soundstage gains in holography and openness. The iBasso DC04PRO is better enjoyed with the power saving mode switched OFF but it is a nice feature to have as it lowers power consumption and extends the host battery duration without compromising too much in sound quality.
Compared to the iBasso DC03PRO ($69)
The iBasso DC03PRO is the single ended brother of the DC04PRO, they share the same appearance and are both based on dual CS43131 chips. The DC03PRO doesn’t have the extra amplification op-amp and uses the embedded headphone amplifier of the DAC chip. The sound of the DC03PRO shares a lot of common characteristics with the single ended output of the DC04PRO when the power saving mode is switched ON. But if you set the power saving mode to OFF then the DC04PRO gains the edge when it comes to technicalities. The choice is pretty obvious here, for single ended only use and if you have a tight budget then the DC03PRO is a great choice while for balanced and mixed use you should go for the DC04PRO.
Compared to the FiiO KA5 ($129)
The KA5 is FiiO’s flagship USB DAC dongle. It uses dual CS43198 DAC chips that are essentially identical with the CS43131 without the embedded headphone amplifier. For amplification duties it utilizes dual SGM8261 AMP op-amps that can provide up to 265mW/32Ω from the balanced output, so the DC04PRO is marginally more powerful. You can’t disable the amplification stage but you can choose between two output modes, Class AB or Class H which lowers quiescent current. The KA5 has also an SPDIF output.
Both devices are compact sized and lightweight with hardware buttons for volume control. A novel feature of the FiiO KA5 is the inclusion of a tiny OLED display which allows the user to configure the device and browse through the menus without the need of a software application. All user selections, like gain and low-pass filter are permanently stored in the memory.
Both USB DAC dongles sound musical and engaging, they have similarities and also some critical differences. The iBasso DC04PRO is cleaner sounding and more transparent. It has a leaner texture but this translates into better definition and layering, especially in the low end, which might not be as weighty and visceral as in the FiiO KA5 but it is more dynamic and impactful. Detail retrieval is deeper in the iBasso and the soundstage is a touch wider with a sharper imaging. The iBasso has faster transients and a surplus of treble energy but the FiiO KA5 is a touch smoother and with a more relaxed presentation of the music. Both devices are natural and realistic sounding, the FiiO KA5 is a touch more organic and the DC04PRO is more like a good solid state amplifier in its character.
Two great USB donges that differ in functionality and sound characteristics and it is up to the reader to decide which one suits him the best.
In the end
The iBasso DC04PRO is a perfect example of how good the USB DAC dongles are becoming and that you don’t have to spend a lot in order to get a high quality product. With excellent sound performance, plenty of power, good efficiency and many customization options, it is one of the best USB DACs that you can buy without the need to break the bank and a lesson from iBasso about how the term “value for money” should be defined from now on.
Copyright – Petros Laskis 2023.
+ Excellent sound quality + Musical and expressive + Crystal clear and transparent + Natural timbre and minimum digital glare + Dynamic and impactful + Hardware volume control + Powerful headphone amplifier + Innovative power saving mode + Low power consumption + Compact and lightweight + Excellent build quality and great looks + Customizable through the UAC application + A lighting cable is also included + Exceptional value for money - The UAC application is only available for Android - User settings are not permanently stored in the memory - Can get a little warm during use
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